Study on the effect of shade net on internal and external quality parameters and chilling injury of fruits of citrus species in the Eastern Cape Province of South Africa
- Moabelo, Phillipine https://orcid.org/0000-0001-9040-1390
- Authors: Moabelo, Phillipine https://orcid.org/0000-0001-9040-1390
- Date: 2021-11
- Subjects: Fruit-culture , Horticulture , Citrus fruits
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22622 , vital:52600
- Description: Pre-harvest technology of shade net is environmental friendly and was found previously to improve fruit growth and yield. In addition, it reduces wind blemishes and sunburn, and effectively act as a buffer against climate fluctuations, such as excessive light, wind and hail damages. However, commercial shade nets are capital intensive; therefore, it is important for farmers to understand its impact on fruit quality that is desired for export market and assess whether the investment is profitable to the industry or not. It was brought to attention that several citrus cultivars grown in Addo, Eastern Cape under 20percent commercial shade net shows sensitivity to chilling injury (CI); however. no information is yet documented about the impact of this technology on fruit quality. To determine the efficacy of 20percent-shade net technology in relation to the control (no shade net), the present study was designed with the objective to compare internal and external quality parameters of ‘Washington and Cambria’ navels, ‘Valley Gold’ mandarin, and ‘Eureka’ lemon fruit grown in shade netted orchards and stored at low temperatures (4 and -0.6°C) for 30 days in Addo area, Eastern Cape. Internal quality attributes assessed includes juice content, °Brixpercent, titratable acid (TA), °Brix:acid ratio and average number of seeds. External quality data assessed include rind colour, and fruit size, firmness/texture and fresh weight loss. For chilling injury, fruits were evaluated by examining the degree of rind pitting and assigning levels of severity namely 0, 1, 2 or 3 where 0 = no pitting detected, 1 = 1 pit, 2 = 2 or more pitting detected and 3 = severe pitting detected. The post-harvest experiments were done on fruits harvested from commercial citrus orchards in Sundays River Valley, between Kirkwood and Addo (33° 34' 0" South, 25° 41' 0" East), in the Eastern Cape Province of South Africa, over two harvesting seasons (2018 and 2019). The ‘Eureka’ lemon and ‘Washington navel’ fruit were collected from Allendale farm; the ‘Cambria’ navel fruits from the Nuwelande and Olifantsbos farms; and the ‘Valley Gold’ mandarin fruits from the Dunbrody/Unifruitti farm. The quality attributes were recorded in the Laboratory of the Citrus Research International (CRI), Port Elizabeth, Eastern Cape, South Africa during Season 1, and in the Horticulture lab of the University of Fort Hare (UFH), Alice, Eastern Cape, South, Africa during Season 2. The experimental layout was a typical pseudo randomised completely block design (RCBD) (not truly randomised) whereby treatments tested were subjected over time (pre-test, post-test). The two treatments i.e. shade vs. control (no shade net) could not be randomly allocated to orchards due to the practical issue of working on a commercial farm, . The sub-factor consisted of three postharvest treatments: Ambiemt temperature (at 0 days storage), 4°C and -0.6°C storages for 30 days. Secondly, an experiment to evaluate the impact of petroleum-based wax mixed with 2-(4-thiazolyl) benzimidazole [thiabendazole (TBZ)] (TBZ: 500 mg.L-1) on shade net vs control fruits was conducted. The fruits were stored at 4°C and - 0.6°C (coated) for 30 days and were evaluated after 7 days storage at room temperature. Shade net did not significantly affect the internal quality attributes of citrus fruits. The 20percent- shade net promoted size of ‘Washington’, ‘Cambria’ navels and ‘Valley Gold’ mandarin, whilst rind colour was not affect. Firmness loss was higher on ‘Eureka’ lemon and ‘Washington’ navel, regardless of the growing conditions and cold storage duration. Rind firmness of ‘Cambria’ navel and ‘Valley Gold’ mandarin were not significantly affected by shade net and storage duration. ‘Eureka’ lemon was found to be more sensitive to CI. However, the application of wax+ TBZ eliminated CI on all 4-cultivars. Therefore, it is recommended to apply wax+ TBZ in packline to eliminate CI and fungal development. , Thesis (MSc) -- Faculty of Science and Agriculture, 2021
- Full Text:
- Date Issued: 2021-11
- Authors: Moabelo, Phillipine https://orcid.org/0000-0001-9040-1390
- Date: 2021-11
- Subjects: Fruit-culture , Horticulture , Citrus fruits
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/22622 , vital:52600
- Description: Pre-harvest technology of shade net is environmental friendly and was found previously to improve fruit growth and yield. In addition, it reduces wind blemishes and sunburn, and effectively act as a buffer against climate fluctuations, such as excessive light, wind and hail damages. However, commercial shade nets are capital intensive; therefore, it is important for farmers to understand its impact on fruit quality that is desired for export market and assess whether the investment is profitable to the industry or not. It was brought to attention that several citrus cultivars grown in Addo, Eastern Cape under 20percent commercial shade net shows sensitivity to chilling injury (CI); however. no information is yet documented about the impact of this technology on fruit quality. To determine the efficacy of 20percent-shade net technology in relation to the control (no shade net), the present study was designed with the objective to compare internal and external quality parameters of ‘Washington and Cambria’ navels, ‘Valley Gold’ mandarin, and ‘Eureka’ lemon fruit grown in shade netted orchards and stored at low temperatures (4 and -0.6°C) for 30 days in Addo area, Eastern Cape. Internal quality attributes assessed includes juice content, °Brixpercent, titratable acid (TA), °Brix:acid ratio and average number of seeds. External quality data assessed include rind colour, and fruit size, firmness/texture and fresh weight loss. For chilling injury, fruits were evaluated by examining the degree of rind pitting and assigning levels of severity namely 0, 1, 2 or 3 where 0 = no pitting detected, 1 = 1 pit, 2 = 2 or more pitting detected and 3 = severe pitting detected. The post-harvest experiments were done on fruits harvested from commercial citrus orchards in Sundays River Valley, between Kirkwood and Addo (33° 34' 0" South, 25° 41' 0" East), in the Eastern Cape Province of South Africa, over two harvesting seasons (2018 and 2019). The ‘Eureka’ lemon and ‘Washington navel’ fruit were collected from Allendale farm; the ‘Cambria’ navel fruits from the Nuwelande and Olifantsbos farms; and the ‘Valley Gold’ mandarin fruits from the Dunbrody/Unifruitti farm. The quality attributes were recorded in the Laboratory of the Citrus Research International (CRI), Port Elizabeth, Eastern Cape, South Africa during Season 1, and in the Horticulture lab of the University of Fort Hare (UFH), Alice, Eastern Cape, South, Africa during Season 2. The experimental layout was a typical pseudo randomised completely block design (RCBD) (not truly randomised) whereby treatments tested were subjected over time (pre-test, post-test). The two treatments i.e. shade vs. control (no shade net) could not be randomly allocated to orchards due to the practical issue of working on a commercial farm, . The sub-factor consisted of three postharvest treatments: Ambiemt temperature (at 0 days storage), 4°C and -0.6°C storages for 30 days. Secondly, an experiment to evaluate the impact of petroleum-based wax mixed with 2-(4-thiazolyl) benzimidazole [thiabendazole (TBZ)] (TBZ: 500 mg.L-1) on shade net vs control fruits was conducted. The fruits were stored at 4°C and - 0.6°C (coated) for 30 days and were evaluated after 7 days storage at room temperature. Shade net did not significantly affect the internal quality attributes of citrus fruits. The 20percent- shade net promoted size of ‘Washington’, ‘Cambria’ navels and ‘Valley Gold’ mandarin, whilst rind colour was not affect. Firmness loss was higher on ‘Eureka’ lemon and ‘Washington’ navel, regardless of the growing conditions and cold storage duration. Rind firmness of ‘Cambria’ navel and ‘Valley Gold’ mandarin were not significantly affected by shade net and storage duration. ‘Eureka’ lemon was found to be more sensitive to CI. However, the application of wax+ TBZ eliminated CI on all 4-cultivars. Therefore, it is recommended to apply wax+ TBZ in packline to eliminate CI and fungal development. , Thesis (MSc) -- Faculty of Science and Agriculture, 2021
- Full Text:
- Date Issued: 2021-11
Effects of paclobutrazol and plant spacing on growth, yield, and after effect on sprout development in seed potatoes (solanum tuberosum l.)
- Jokazi, Khuselo Bernad https://orcid.org/0000-0002-8620-9838
- Authors: Jokazi, Khuselo Bernad https://orcid.org/0000-0002-8620-9838
- Date: 2021-01
- Subjects: Potatoes , Plant regulators
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/21323 , vital:48406
- Description: Potato (Solanum tuberosum L.) is an herbaceous plant that belongs to the genus Solanum, in the Solanaceae family which is comprised of about 2 800 species (Sahair et al., 2018). Potato domestication can be traced back to the sixteenth century in the South American continent (Hawkes, 1978). The potato crop became a staple food for greater parts of the world towards the end of the seventeenth century. It is not clear when the crop was introduced to the African continent, although the literature indicates that it was grown in some parts of the continent by the late seventeenth century (Hawkes, 1978). Potato is a very bulky crop and is a source of high energy per given area of land (Tsegaw, 2005). Nutritionally, the crop is rich in carbohydrates and provides a considerable amount of protein, with a good balance of amino acids, vitamins (C, B6, and B1, folate), minerals (potassium, phosphorus, calcium, and magnesium), and the micronutrients iron and zinc. Potatoes are also a source of high dietary fiber, especially when eaten unpeeled. In addition, potatoes are rich in antioxidants, including polyphenols, vitamin C, carotenoids, and tocopherols (Bradshaw and Ramsay, 2009). Potatoes play a very important role in the global food system. It is South Africa’s most important vegetable crop (DAFF, 2012). Worldwide, it ranks fourth topmost important food crops following wheat, maize, and rice (Esmaielpour et al., 2011; Bradshaw and Ramsay, 2009), followed by barley (Allemann et al., 2003). South Africa is the 27th largest producer in the world and the 3rd largest producer in Africa after Egypt and Malawi (FAOSTAT, 2015). In the year 2014, potatoes were produced in 51 435 hectares of land, which yielded over 2 million tons (DAFF, 2015). This crop is produced in sixteen producing regions throughout South Africa with the Limpopo, Free State, Western Cape, Mpumalanga, KwaZulu-Natal, and Eastern Cape provinces being the leading regions (DAFF, 2015). Because of the different climatic regions in South Africa, potatoes are planted at different times of the year. As a result, the country enjoys fresh potatoes throughout the year (DAFF, 2014). According to the Potato Industry Research Strategy 2014-17 under Potato South Africa, the past few years have seen a decrease in the area of land under potato production, with an increase in the average yield per area. This yield increment can be accredited to an increase in the production under irrigation system, the use of improved cultivars and seed quality, and the application of research results (PSA, 2014). World potato production indicates that intensive cultivation has led to an increment of potato yields between 1960 and 1999, even though there was a reduction in the area planted with the crop (Fabeiro et al., 2001). However, there is a large gap between potential potato yield and actual yield per hectare. Research undoubtedly holds great potential for narrowing this gap. In order to do so, there is a need to understand the factors limiting potato yield. Temperature, plant spacing, and seed tuber quality are amongst the most significant factors affecting potato growth, yield, and quality. Potatoes are very adaptive; at present, they can be produced in different climatic regions. They are temperate crops, which prefer a cool and humid climate (Haverkort, 1990), but care should be taken to avoid high-stress periods such as temperature extremes. The optimum temperature for haulm growth and net photosynthesis is in the range between 15℃ and 25℃, and 20℃ is the optimum temperature for tuberization. Tuberization is inhibited by temperatures above 29℃, as the photoassimilate partitioning towards the tubers is decreased, leading to an increase in shoot growth (Gawronska et al., 1992). Plant spacing is usually determined by the target market and cultivar. , Thesis (MSc) -- Faculty of Science and Agriculture, 2021
- Full Text:
- Date Issued: 2021-01
- Authors: Jokazi, Khuselo Bernad https://orcid.org/0000-0002-8620-9838
- Date: 2021-01
- Subjects: Potatoes , Plant regulators
- Language: English
- Type: Master's theses , text
- Identifier: http://hdl.handle.net/10353/21323 , vital:48406
- Description: Potato (Solanum tuberosum L.) is an herbaceous plant that belongs to the genus Solanum, in the Solanaceae family which is comprised of about 2 800 species (Sahair et al., 2018). Potato domestication can be traced back to the sixteenth century in the South American continent (Hawkes, 1978). The potato crop became a staple food for greater parts of the world towards the end of the seventeenth century. It is not clear when the crop was introduced to the African continent, although the literature indicates that it was grown in some parts of the continent by the late seventeenth century (Hawkes, 1978). Potato is a very bulky crop and is a source of high energy per given area of land (Tsegaw, 2005). Nutritionally, the crop is rich in carbohydrates and provides a considerable amount of protein, with a good balance of amino acids, vitamins (C, B6, and B1, folate), minerals (potassium, phosphorus, calcium, and magnesium), and the micronutrients iron and zinc. Potatoes are also a source of high dietary fiber, especially when eaten unpeeled. In addition, potatoes are rich in antioxidants, including polyphenols, vitamin C, carotenoids, and tocopherols (Bradshaw and Ramsay, 2009). Potatoes play a very important role in the global food system. It is South Africa’s most important vegetable crop (DAFF, 2012). Worldwide, it ranks fourth topmost important food crops following wheat, maize, and rice (Esmaielpour et al., 2011; Bradshaw and Ramsay, 2009), followed by barley (Allemann et al., 2003). South Africa is the 27th largest producer in the world and the 3rd largest producer in Africa after Egypt and Malawi (FAOSTAT, 2015). In the year 2014, potatoes were produced in 51 435 hectares of land, which yielded over 2 million tons (DAFF, 2015). This crop is produced in sixteen producing regions throughout South Africa with the Limpopo, Free State, Western Cape, Mpumalanga, KwaZulu-Natal, and Eastern Cape provinces being the leading regions (DAFF, 2015). Because of the different climatic regions in South Africa, potatoes are planted at different times of the year. As a result, the country enjoys fresh potatoes throughout the year (DAFF, 2014). According to the Potato Industry Research Strategy 2014-17 under Potato South Africa, the past few years have seen a decrease in the area of land under potato production, with an increase in the average yield per area. This yield increment can be accredited to an increase in the production under irrigation system, the use of improved cultivars and seed quality, and the application of research results (PSA, 2014). World potato production indicates that intensive cultivation has led to an increment of potato yields between 1960 and 1999, even though there was a reduction in the area planted with the crop (Fabeiro et al., 2001). However, there is a large gap between potential potato yield and actual yield per hectare. Research undoubtedly holds great potential for narrowing this gap. In order to do so, there is a need to understand the factors limiting potato yield. Temperature, plant spacing, and seed tuber quality are amongst the most significant factors affecting potato growth, yield, and quality. Potatoes are very adaptive; at present, they can be produced in different climatic regions. They are temperate crops, which prefer a cool and humid climate (Haverkort, 1990), but care should be taken to avoid high-stress periods such as temperature extremes. The optimum temperature for haulm growth and net photosynthesis is in the range between 15℃ and 25℃, and 20℃ is the optimum temperature for tuberization. Tuberization is inhibited by temperatures above 29℃, as the photoassimilate partitioning towards the tubers is decreased, leading to an increase in shoot growth (Gawronska et al., 1992). Plant spacing is usually determined by the target market and cultivar. , Thesis (MSc) -- Faculty of Science and Agriculture, 2021
- Full Text:
- Date Issued: 2021-01
Studies on vine storage methods, planting techniques, paclobutrazol treatment, planting density and weevil management on sweetpotato (ipomoea batatas l.lam) cultivars promoted in South Africa
- Hlerema, Igenicious Nicholas https://orcid.org/0000-0002-6111-404X
- Authors: Hlerema, Igenicious Nicholas https://orcid.org/0000-0002-6111-404X
- Date: 2019-09
- Subjects: Sweet potatoes , Seed treatment
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/21580 , vital:49336
- Description: Sweetpotato (Ipomoea batatas L. LAM) is a major world staple food. It is a versatile, nutrient-rich crop well suited for production by emerging farmers, and thus a popular crop in subtropical parts of South Africa. The crop has several advantages such as producing more bioweight and nutrients per unit land area and per unit time than most other staple crops such as maize; adaptation to a broad range of agro-ecological conditions; and ability to compete and crowd out weeds, and affected by a relatively small number of pests and diseases. Root and vine yields achieved by emerging farmers are low and cultivation systems need to be optimized. The general objective of the research was to develop nursery practices that ensure a sustainable supply of sweetpotato planting materials and cultural practices that maximize yield, eating and nutritional quality of sweetpotato roots. The specific objectives were (i) to evaluate the effect of polyethylene and hessian bags on vine quality and vine survival period; (ii) to compare planting techniques and vine length; (iii) to determine the effect of paclobutrazol on storage root yield; and (iv) to evaluate the effect of Beauveria bassiana as biological control for sweetpotato weevil. The vine storage experiment aimed at identifying the best type of storage bags that keep the vines of “Bophelo”, an orange-fleshed sweetpotato cultivar in good quality for a longer period of time. The study involved two factors, viz storage bag type and storage period. The experiment tried to address (1) a sustainable seed system in sweetpotato and (2) production stimulated by cultural practises. Vines were stored in polyethylene bag without holes, polyethylene bag with 12 holes and dry hessian bag over 3, 6, 9, 12 and 15 days at an ambient temperature of 250C. The incremental cost-effectiveness ratio (ICER) was calculated to determine the cost-effectiveness of using the polyethylene bags with holes or without and the hessian bags. The results of the study showed that hessian bags store vines over a longer period (12 days) compared to the polyethylene bags without holes (6 days); however, hessian bags are more expensive. Polyethylene bags can still be used for transporting and storing vines if the farmer is within a short distance from the seed source and plants the vines within the 6 day period. Polyethylene bags with 12 holes are recommended since they allow maximum air circulation and extend storage period (9 days). Optimum planting techniques can help sweetpotato farmers to achieve optimal yields. Newly developed cultivars from the Agricultural Research Council have not been tested to determine the best planting techniques. A trial was conducted to investigate the effect of two planting orientations (horizontal and vertical) and different vine length (2, 3 and 4 subterranean nodes) of 3 released varieties, Blesbock, Bophelo and Ndou on storage root yield of sweetpotato. A factorial experiment was laid out in a randomised complete block design with three replications during two cropping seasons (2014/15 and 2015/16). The data collected in both experiments included total storage root yield, marketable storage root yield, and number of storage roots per size class. Significant differences were detected for the interaction of all factors on the number roots per size class, total storage root yield, and total average root weight. Vertical and horizontal planting per se showed no significance differences for all the sweetpotato root growth parameters such as total yield. However, the more the number of subterainian node the more yield we got for the commercial cultivar Blesbok. Paclobutrazol (PBZ) is a plant growth retardant hormone. This hormone might, therefore, be useful for sweetpotato growers to achieve higher plant populations per hectare because it would reduce the plant canopy. However, it should also be checked if the PBZ application does not affect nutrient content of roots and leaves, especially the beta-carotene content of the orange-fleshed cultivars. The objective of this study was, therefore, to determine the effect of PBZ on sweetpotato shoot growth, storage root yield and beta-carotene content of sweetpotato leaves and storage roots. The field trial was repeated over two seasons, namely 2014/15 and 2015/16 crop seasons. These field experiments were arranged as a split plot experiment. The main plots were allocated to four PBZ levels, laid-out as randomised complete block design, and treatment combinations of two cultivars (Bophelo and Blesbok) and two plants spacing (20 cm and 30 cm) were randomly allocated into the subplots. The PBZ levels applied were 0, 100, 200 and 300 mg of active ingredient per litre of water, sprayed 4 weeks after planting. Root yield and bioweight accumulation were recorded. In addition, a pot experiment was set up using cultivar Bophelo and 0 mg, 100 mg and 200 mg/l active ingredient of PBZ sprayed 4 weeks after planting. Leaf and root samples (150g and 400g of a composite sample respectively) were collected and analysed for total phenols, total flavonoids, vitamin C and beta-carotene. The field trial results revealed significant differences (P<0.05) in leaf and stem weight of the plants treated with different PBZ levels applied. The control (0 mg PBZ rate) had the highest leaf and stem weight. There were no significant differences in root yield among the PBZ levels. The results of leaf and root analysis for the Bophelo cultivar showed significant differences (P<0.05) in total phenols, total flavonoids, vitamin C and beta-carotene in leaf samples of the three levels of PBZ applied. The beta-carotene for the leaf increased at the 100 mg/l PBZ level. As the paclobutrazol level increased there was a reduction in the beta-carotene content for the roots from 18,91 to 13,97 to 10,77 mg/100g dry weight for 0 mg/l, 100 mg/l and 200mg/l, respectively. Application of PBZ to sweetpotato reduces the bioweight yield but does not have an effect on the root yield. Thus a higher plant density can be used to achieve higher yield and returns on investment. The leaves can be used as a relish and can be sold to supplement income. However, PBZ further reduces the beta-carotene content of the roots and is not recommended for use with orange-fleshed cultivars, where the objective is to enrich food with vitamin A. Sweetpotato weevils (Cylas puncticollis and C. formicarius) are notorious pests of sweetpotato. It causes severe losses in marketable root yield. The study tested the use of Beauveria bassiana (Balsamo Vuillemin) (Deuteromycota: Hyphomycetes) for controlling sweetpotato weevils. Experiments were conducted over two cropping seasons using four treatments: 1) dipping sweetpotato cuttings in solution of 1 g/litre B. bassiana before planting, 2) spraying with a registered chemical (Deltametrin) at 50 ml/100 litre of water starting 2 weeks after panting at biweekly basis for four months after planting, 3) spraying the leaves with B. bassiana (10 g/100 litre) starting 2 weeks on biweekly basis for four months after planting; and 4) control (sprayed with water). The research was arranged as split plot experiment, where the pest management treatments assigned to the main plots as per Latin square design and the three sweetpotato cultivars (Bophelo, Ndou and Blesbok) were randomly put in the subplot in each main plot. Spraying with B. bassiana significantly reduced the percentage of insect-damaged roots (9.95percent) compared to the control (22.48percent). Dipping sweetpotato cuttings in solution of 1 g/litre B. bassiana before planting did not significantly reduce the number of insect damaged roots (18.63percent insect damage). There was no significant difference between the chemical spray (8.2percent insect damage) and spraying with B. bassiana (9.95percent insect damage). The investigation indicated that B. bassiana can be considered as an alternative control method for the sweetpotato weevil. Use of biological control is less expensive and beneficial to reduce adverse effects on the environment and human health. , Thesis (PhD) -- Faculty of Science and Agriculture, 2019
- Full Text:
- Date Issued: 2019-09
- Authors: Hlerema, Igenicious Nicholas https://orcid.org/0000-0002-6111-404X
- Date: 2019-09
- Subjects: Sweet potatoes , Seed treatment
- Language: English
- Type: Doctoral theses , text
- Identifier: http://hdl.handle.net/10353/21580 , vital:49336
- Description: Sweetpotato (Ipomoea batatas L. LAM) is a major world staple food. It is a versatile, nutrient-rich crop well suited for production by emerging farmers, and thus a popular crop in subtropical parts of South Africa. The crop has several advantages such as producing more bioweight and nutrients per unit land area and per unit time than most other staple crops such as maize; adaptation to a broad range of agro-ecological conditions; and ability to compete and crowd out weeds, and affected by a relatively small number of pests and diseases. Root and vine yields achieved by emerging farmers are low and cultivation systems need to be optimized. The general objective of the research was to develop nursery practices that ensure a sustainable supply of sweetpotato planting materials and cultural practices that maximize yield, eating and nutritional quality of sweetpotato roots. The specific objectives were (i) to evaluate the effect of polyethylene and hessian bags on vine quality and vine survival period; (ii) to compare planting techniques and vine length; (iii) to determine the effect of paclobutrazol on storage root yield; and (iv) to evaluate the effect of Beauveria bassiana as biological control for sweetpotato weevil. The vine storage experiment aimed at identifying the best type of storage bags that keep the vines of “Bophelo”, an orange-fleshed sweetpotato cultivar in good quality for a longer period of time. The study involved two factors, viz storage bag type and storage period. The experiment tried to address (1) a sustainable seed system in sweetpotato and (2) production stimulated by cultural practises. Vines were stored in polyethylene bag without holes, polyethylene bag with 12 holes and dry hessian bag over 3, 6, 9, 12 and 15 days at an ambient temperature of 250C. The incremental cost-effectiveness ratio (ICER) was calculated to determine the cost-effectiveness of using the polyethylene bags with holes or without and the hessian bags. The results of the study showed that hessian bags store vines over a longer period (12 days) compared to the polyethylene bags without holes (6 days); however, hessian bags are more expensive. Polyethylene bags can still be used for transporting and storing vines if the farmer is within a short distance from the seed source and plants the vines within the 6 day period. Polyethylene bags with 12 holes are recommended since they allow maximum air circulation and extend storage period (9 days). Optimum planting techniques can help sweetpotato farmers to achieve optimal yields. Newly developed cultivars from the Agricultural Research Council have not been tested to determine the best planting techniques. A trial was conducted to investigate the effect of two planting orientations (horizontal and vertical) and different vine length (2, 3 and 4 subterranean nodes) of 3 released varieties, Blesbock, Bophelo and Ndou on storage root yield of sweetpotato. A factorial experiment was laid out in a randomised complete block design with three replications during two cropping seasons (2014/15 and 2015/16). The data collected in both experiments included total storage root yield, marketable storage root yield, and number of storage roots per size class. Significant differences were detected for the interaction of all factors on the number roots per size class, total storage root yield, and total average root weight. Vertical and horizontal planting per se showed no significance differences for all the sweetpotato root growth parameters such as total yield. However, the more the number of subterainian node the more yield we got for the commercial cultivar Blesbok. Paclobutrazol (PBZ) is a plant growth retardant hormone. This hormone might, therefore, be useful for sweetpotato growers to achieve higher plant populations per hectare because it would reduce the plant canopy. However, it should also be checked if the PBZ application does not affect nutrient content of roots and leaves, especially the beta-carotene content of the orange-fleshed cultivars. The objective of this study was, therefore, to determine the effect of PBZ on sweetpotato shoot growth, storage root yield and beta-carotene content of sweetpotato leaves and storage roots. The field trial was repeated over two seasons, namely 2014/15 and 2015/16 crop seasons. These field experiments were arranged as a split plot experiment. The main plots were allocated to four PBZ levels, laid-out as randomised complete block design, and treatment combinations of two cultivars (Bophelo and Blesbok) and two plants spacing (20 cm and 30 cm) were randomly allocated into the subplots. The PBZ levels applied were 0, 100, 200 and 300 mg of active ingredient per litre of water, sprayed 4 weeks after planting. Root yield and bioweight accumulation were recorded. In addition, a pot experiment was set up using cultivar Bophelo and 0 mg, 100 mg and 200 mg/l active ingredient of PBZ sprayed 4 weeks after planting. Leaf and root samples (150g and 400g of a composite sample respectively) were collected and analysed for total phenols, total flavonoids, vitamin C and beta-carotene. The field trial results revealed significant differences (P<0.05) in leaf and stem weight of the plants treated with different PBZ levels applied. The control (0 mg PBZ rate) had the highest leaf and stem weight. There were no significant differences in root yield among the PBZ levels. The results of leaf and root analysis for the Bophelo cultivar showed significant differences (P<0.05) in total phenols, total flavonoids, vitamin C and beta-carotene in leaf samples of the three levels of PBZ applied. The beta-carotene for the leaf increased at the 100 mg/l PBZ level. As the paclobutrazol level increased there was a reduction in the beta-carotene content for the roots from 18,91 to 13,97 to 10,77 mg/100g dry weight for 0 mg/l, 100 mg/l and 200mg/l, respectively. Application of PBZ to sweetpotato reduces the bioweight yield but does not have an effect on the root yield. Thus a higher plant density can be used to achieve higher yield and returns on investment. The leaves can be used as a relish and can be sold to supplement income. However, PBZ further reduces the beta-carotene content of the roots and is not recommended for use with orange-fleshed cultivars, where the objective is to enrich food with vitamin A. Sweetpotato weevils (Cylas puncticollis and C. formicarius) are notorious pests of sweetpotato. It causes severe losses in marketable root yield. The study tested the use of Beauveria bassiana (Balsamo Vuillemin) (Deuteromycota: Hyphomycetes) for controlling sweetpotato weevils. Experiments were conducted over two cropping seasons using four treatments: 1) dipping sweetpotato cuttings in solution of 1 g/litre B. bassiana before planting, 2) spraying with a registered chemical (Deltametrin) at 50 ml/100 litre of water starting 2 weeks after panting at biweekly basis for four months after planting, 3) spraying the leaves with B. bassiana (10 g/100 litre) starting 2 weeks on biweekly basis for four months after planting; and 4) control (sprayed with water). The research was arranged as split plot experiment, where the pest management treatments assigned to the main plots as per Latin square design and the three sweetpotato cultivars (Bophelo, Ndou and Blesbok) were randomly put in the subplot in each main plot. Spraying with B. bassiana significantly reduced the percentage of insect-damaged roots (9.95percent) compared to the control (22.48percent). Dipping sweetpotato cuttings in solution of 1 g/litre B. bassiana before planting did not significantly reduce the number of insect damaged roots (18.63percent insect damage). There was no significant difference between the chemical spray (8.2percent insect damage) and spraying with B. bassiana (9.95percent insect damage). The investigation indicated that B. bassiana can be considered as an alternative control method for the sweetpotato weevil. Use of biological control is less expensive and beneficial to reduce adverse effects on the environment and human health. , Thesis (PhD) -- Faculty of Science and Agriculture, 2019
- Full Text:
- Date Issued: 2019-09
Effects of nitrogen and phosphorus rates, leaf age and drying technique on growth and nutritional contents of Moringa oleifera
- Authors: Sokombela, Asanda
- Date: 2019
- Subjects: Moringa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12117 , vital:39153
- Description: In general, smallholder farmers tend to use large quantities of soil nutrients without replenishment with manure, compost and fertiliser in order to replace the soil nutrients that are lost. Considering the low soil fertility status of soils in South Africa, this study was conducted with an aim of developing agronomic protocols for the production of moringa in order to fight malnutrition and produce supplement feed for animals. Moringa contains various nutrients and chemicals, such as, protein, which are sensitive to heat, and there is therefore a need to establish the best drying method which does not affect the nutrient content and quality of moringa. Physiological age is probably the most important factor influencing the mineral composition of plants. The relationship between nutrient concentration and leaf age is not fundamentally altered by crop load, soil type, climate or cultural practices, such that nutrients may be displaced vertically by the level of supply. Leaf age is one of the factors that affect the distribution of nutrients in the leaves of plants. Therefore, studies were conducted to evaluate the response of Moringa oleifera leaf yield and nutritional content to nitrogen and phosphorus rates, leaf age/position, and drying techniques. The experiments were conducted at the University of Fort Hare Alice Campus research farm. The experiment that investigated the effect of N and P rates was carried out in potted plants filled fine silica sand. The seeds were sown on black polythene bags, filled with a mixture of soil, pine bark and goat manure (at 1:2:1 ratio, respectively) at a depth of 2 cm. At 30 cm height, the seedlings were transplanted into 5-liter pots, which were filled with building sand as growing media. The experiment was a 4 x 3 factorial, with four levels of nitrogen (100, 200, 300 and 400 kg/ha) and three levels of phosphorus (40, 80 and 120 kg/ha). The experiment was laid-out as randomised complete block design (RCBD), with 12 treatment combinations replicated four times. All experimental units received the same amount of potassium (731kg/ha) in the form of KCl. Nitrogen treatments which were applied were split in two equal applications, at transplanting stage and 4 weeks later. The phosphorus rates were applied as superphosphate once mixed to the potting media before transplanting. Growth parameters such as plant height, root collar diameters, number of leaves, dry and fresh leaf masses were measured. Powdered dry leaves were also analysed to determine iv metabolite such as crude protein, ash, moisture, fat and fibre constituents (ADF and NDF). Micro and macro mineral nutrients were also determined using atomic absorption spectroscopy technique (AAS). The results showed that growth of moringa significantly increased through the application of fertilizer. The results from the (ANOVA) table showed no interaction between phosphorus and nitrogen on growth parameters such as number of leaves, stem width and plant height of moringa in this study. Nitrogen levels, as treatments, have significantly affected the growth of the plant. However, phosphorus, as a treatment, showed no significant difference on growth parameteres of Moringa. It was evident that trees that received the highest nitrogen rate (400 kg/ha) resulted in thickest stem girth, tallest trees and the highest number of leaves. The overall results revealed that moringa leaf powder contained appreciable amount nutrients. Crude protein was notably high (38.23%) in the trees that received the highest phosphorus and nitrogen combination treatment (400 kg/ha N x 120 kg/ha P treatment combination. The highest ash content of (14.17%) and (14.21%) were recorded from the trees that received treatment combination of 200 kg/ha N x 80 kg/ha P and 100 kg/ha N x 120 kg/ha P, and significantly differed from the rest of the other treatment combinations. The fat content steadily increased with an increase in nitrogen rate. Increase in P level resulted in a decrease in fat content. The overall findings confirm that combinations of the higher levels of N and P result in a decrease in fat content. The variation in the metabolite nutrients and mineral nutrient values may be due to differences in age of the leaves or positions and possibly due to different stages of maturity of leaves. The second experiment was conducted in the field at the research farm. The aim was to evaluate the effect of leaf age/position on nutrient distribution of moringa. The seeds were sown in black polythene bags at a depth of 2 cm. The bags were filled with a mixture of 1 part of soil, 2 parts of pine bark: and 1 part of manure. The seedlings were transplanted into the field when they reached the height of 30cm. Plants were laid-out as a CRD design with 5 replications. Three leaf positions, upper, middle and basal leaves, were used as treatments to determine the nutrient variation within a parent plant. Leaves of each position were harvested separately, washed with tap water and air-dried in shade condition. The dried leaves were analysed for metabolite and mineral content. The Association of official agricultural chemists (AOAC) methods were used to determine protein, fat, fibre, and ash. Atomic absorption spectrometry (AAS) technique was used to analyse minerals v such as iron, zinc, copper, manganese and macro-minerals such as calcium, magnesium, potassium, sodium and phosphorus. The study showed that ash, fat, NDF and ADF contents were significantly higher in the basal leaves as compared to that in the middle and upper leaves. However, moisture and crude protein contents were significantly higher in the upper leaves compared to both in the middle and basal leaves. The basal leaves accumulated significantly higher Ca, Mg, K, Na and Mn contents. The concentrations of P, Zn, Cu and Fe were, on the other hand, significantly higher in the younger leaves compared to that in the middle and basal leaves. It can be concluded that the upper (younger) leaves contain enough nutrition to satisfy the dietary requirements. In addition, these leaves have low levels of oxalate, cyanide and nitrate, which can cause health problems. To determine the effect of drying method on nutrition content of moringa leaves, three drying methods (shade-, sun- and oven-drying methods) were applied as treatments. Moringa plants were grown at the Research Farm of the University of Fort Hare, Alice campus. The leaves were harvested, thoroughly mixed, washed with tap water and put into 15 brown paper bags. The 15 samples (paper bags) were distributed to the three drying treatments (each treatment replicated 5 times). The dried samples were analysed for metabolites and mineral content as per AOAC and AAS methods, respectively. The study showed that shade-drying method retained higher metabolites. Thus, this study recommends the shade-drying method in preserving moringa leaves.
- Full Text:
- Date Issued: 2019
- Authors: Sokombela, Asanda
- Date: 2019
- Subjects: Moringa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/12117 , vital:39153
- Description: In general, smallholder farmers tend to use large quantities of soil nutrients without replenishment with manure, compost and fertiliser in order to replace the soil nutrients that are lost. Considering the low soil fertility status of soils in South Africa, this study was conducted with an aim of developing agronomic protocols for the production of moringa in order to fight malnutrition and produce supplement feed for animals. Moringa contains various nutrients and chemicals, such as, protein, which are sensitive to heat, and there is therefore a need to establish the best drying method which does not affect the nutrient content and quality of moringa. Physiological age is probably the most important factor influencing the mineral composition of plants. The relationship between nutrient concentration and leaf age is not fundamentally altered by crop load, soil type, climate or cultural practices, such that nutrients may be displaced vertically by the level of supply. Leaf age is one of the factors that affect the distribution of nutrients in the leaves of plants. Therefore, studies were conducted to evaluate the response of Moringa oleifera leaf yield and nutritional content to nitrogen and phosphorus rates, leaf age/position, and drying techniques. The experiments were conducted at the University of Fort Hare Alice Campus research farm. The experiment that investigated the effect of N and P rates was carried out in potted plants filled fine silica sand. The seeds were sown on black polythene bags, filled with a mixture of soil, pine bark and goat manure (at 1:2:1 ratio, respectively) at a depth of 2 cm. At 30 cm height, the seedlings were transplanted into 5-liter pots, which were filled with building sand as growing media. The experiment was a 4 x 3 factorial, with four levels of nitrogen (100, 200, 300 and 400 kg/ha) and three levels of phosphorus (40, 80 and 120 kg/ha). The experiment was laid-out as randomised complete block design (RCBD), with 12 treatment combinations replicated four times. All experimental units received the same amount of potassium (731kg/ha) in the form of KCl. Nitrogen treatments which were applied were split in two equal applications, at transplanting stage and 4 weeks later. The phosphorus rates were applied as superphosphate once mixed to the potting media before transplanting. Growth parameters such as plant height, root collar diameters, number of leaves, dry and fresh leaf masses were measured. Powdered dry leaves were also analysed to determine iv metabolite such as crude protein, ash, moisture, fat and fibre constituents (ADF and NDF). Micro and macro mineral nutrients were also determined using atomic absorption spectroscopy technique (AAS). The results showed that growth of moringa significantly increased through the application of fertilizer. The results from the (ANOVA) table showed no interaction between phosphorus and nitrogen on growth parameters such as number of leaves, stem width and plant height of moringa in this study. Nitrogen levels, as treatments, have significantly affected the growth of the plant. However, phosphorus, as a treatment, showed no significant difference on growth parameteres of Moringa. It was evident that trees that received the highest nitrogen rate (400 kg/ha) resulted in thickest stem girth, tallest trees and the highest number of leaves. The overall results revealed that moringa leaf powder contained appreciable amount nutrients. Crude protein was notably high (38.23%) in the trees that received the highest phosphorus and nitrogen combination treatment (400 kg/ha N x 120 kg/ha P treatment combination. The highest ash content of (14.17%) and (14.21%) were recorded from the trees that received treatment combination of 200 kg/ha N x 80 kg/ha P and 100 kg/ha N x 120 kg/ha P, and significantly differed from the rest of the other treatment combinations. The fat content steadily increased with an increase in nitrogen rate. Increase in P level resulted in a decrease in fat content. The overall findings confirm that combinations of the higher levels of N and P result in a decrease in fat content. The variation in the metabolite nutrients and mineral nutrient values may be due to differences in age of the leaves or positions and possibly due to different stages of maturity of leaves. The second experiment was conducted in the field at the research farm. The aim was to evaluate the effect of leaf age/position on nutrient distribution of moringa. The seeds were sown in black polythene bags at a depth of 2 cm. The bags were filled with a mixture of 1 part of soil, 2 parts of pine bark: and 1 part of manure. The seedlings were transplanted into the field when they reached the height of 30cm. Plants were laid-out as a CRD design with 5 replications. Three leaf positions, upper, middle and basal leaves, were used as treatments to determine the nutrient variation within a parent plant. Leaves of each position were harvested separately, washed with tap water and air-dried in shade condition. The dried leaves were analysed for metabolite and mineral content. The Association of official agricultural chemists (AOAC) methods were used to determine protein, fat, fibre, and ash. Atomic absorption spectrometry (AAS) technique was used to analyse minerals v such as iron, zinc, copper, manganese and macro-minerals such as calcium, magnesium, potassium, sodium and phosphorus. The study showed that ash, fat, NDF and ADF contents were significantly higher in the basal leaves as compared to that in the middle and upper leaves. However, moisture and crude protein contents were significantly higher in the upper leaves compared to both in the middle and basal leaves. The basal leaves accumulated significantly higher Ca, Mg, K, Na and Mn contents. The concentrations of P, Zn, Cu and Fe were, on the other hand, significantly higher in the younger leaves compared to that in the middle and basal leaves. It can be concluded that the upper (younger) leaves contain enough nutrition to satisfy the dietary requirements. In addition, these leaves have low levels of oxalate, cyanide and nitrate, which can cause health problems. To determine the effect of drying method on nutrition content of moringa leaves, three drying methods (shade-, sun- and oven-drying methods) were applied as treatments. Moringa plants were grown at the Research Farm of the University of Fort Hare, Alice campus. The leaves were harvested, thoroughly mixed, washed with tap water and put into 15 brown paper bags. The 15 samples (paper bags) were distributed to the three drying treatments (each treatment replicated 5 times). The dried samples were analysed for metabolites and mineral content as per AOAC and AAS methods, respectively. The study showed that shade-drying method retained higher metabolites. Thus, this study recommends the shade-drying method in preserving moringa leaves.
- Full Text:
- Date Issued: 2019
Rose-scented geranium oil yield and composition as affected by leaf age, herbage drying and paclobutrazol
- Authors: Dyafta, Viwe
- Date: 2018
- Subjects: Essences and essential oils Rose geranium oil
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/10747 , vital:35733
- Description: Essential oil of rose scented-geranium is highly versatile and this makes it a very important essential oil in aromatherapy, medicine and cosmetics as well as in flavouring of food and drinks for different industries. The value of the essential oil is directly related to the quality of the oil. Therefore, it is important that the geranium growers take good care of agricultural practices in the production of essential oils as it is a crucial step where oil quality and yield is either obtained or lost. Thus, growing conditions and harvesting time must be cautiously established and controlled including herbage drying to ensure optimum yields and high quality of rose-scented geranium oil. The geranium oil production industry in South Africa is still expanding and oil yield & quality variation is important. This study was undertaken to determine the effects of herbage drying and method, leaf age and paclobutrazol concentrations on oil yield and quality of rose-scented geranium. The responses of oil yield and quality to drying effect was conducted on plant materials which were harvested from the University of Fort Hare Research Farm and glasshouse in December 2014 and October 2015. To determine the effect of drying method on essential oil yield and composition of rose-scented geranium the harvested leaves were dried in direct sunlight (20-35℃) and in a shade conditions (25℃/room temperature). Essential oil was obtained by hydro-distillation using a Clevenger apparatus. The oil samples were analysed by gas chromatography (GC) at the Dohne Agricultural institute. The major components of the oil conducted under the shade method were Linalool (5.58 percent), Menthone (0.68 percent), Citronellol (36.14 percent), Geraniol (7.29 percent), CitronellylFormate (15.39 percent) and GeranylFormate (3.30 percent), whereas those that were sun dried comprised of Linalool (3.56percent), Menthone (0.76 percent), Citronellol (32.25 percent), Geraniol (6.49 percent), CitronellylFormate (14.84 percent) and GeranylFormate (3.15 percent). The analysis of variance showed that freshly dried herbage followed by shade drying is suitable for highest oil yield. In addition, changes in essential oil composition and oil yield with leaf age in rose-scented geranium (Pelargonium capitatum x P. radens cv. Rose) were investigated in a glasshouse of the University of Fort Hare, during January to April and April to August 2012. The plants were allowed to grow to about 12-leaf stage. From top to bottom, the leaves were put into five groups (each group comprising two successive leaves, Pairs 1, 2, 3, 4 and 5). Leaf growth (leaf fresh and dry mass), and essential oil yield and composition data were collected and compared. The results indicated that, leaf fresh and dry mass data were significantly lower in the top-most (youngest leaves) as compared with the rest of the leaf pairs harvested. Essential oil in the youngest leaves was colourless, but as the leaves advanced with age, the oil tended to have a blue-green colour. Oil content (on dry mass basis) from the top to bottom, for Leaf Pairs 1, 2, 3, 4, and 5 were about 7.0, 4.9, 3.2, 2.4, 1.9 percent, respectively. Oil yield showed a significant increase in the second youngest pair of leaves and progressively declined, resulting in a significant lower yield in the oldest leaves. Leaf Pairs 1, 2, 3, 4 and 5, contributed about 19.3, 22.0, 17.71, 12.03 and 8.5 percent of the total yield per branch, respectively. Citronellol:Geraniol ratio was significantly lower in the young leaves than in the old leaves. Linalool and Geranylformate concentrations were the highest in the youngest leaves, and the opposite was observed in isomenthone. Other essential oil components did respond to leaf age. In support of research by Góra et al. (2002), Motsa et al. (2006) and Southwell and Stiff (1989), the current results indicate that early leaf age affects essential oil yield and composition. Thus, shorter regrowth cycles would increase essential oil yield and quality of rose-scented geranium. The paclobutrazol experiment was conducted in a glasshouse at the University of Fort Hare, Alice. A randomized complete block design with four replications was applied. One month after cutting back of the plants, PBZ was applied at the rates of 0, 100, 200 and 300 mg/l on the regrowth and harvested at four months of age. Data, such as chlorophyll content, plant circumference, plant height, fresh and dry mass and oil composition, were determined. The results highlighted that with an increase in PBZ concentration, total herbage mass and plant height tended to decline (Esmaielpour et al., 2011). Thus, in most cases herbage fresh and dry weight of treated plants had lower weight than the control. Paclobutrazol significantly reduced canopy circumference. There was no significant difference (P< 0.05) in oil yield and composition. Furthermore, observations showed that plants receiving PBZ had a deep green colour although the chlorophyll data did not show a significant difference. These results clearly show that PBZ helps geranium plants with compact canopy, which would enable farmers to increase income by increasing planting density, reducing distillation cost of the herbage volume and mass without reducing oil yield per plant. The findings, add another dimension to practical use of this hormone for commercial cultivation.
- Full Text:
- Date Issued: 2018
- Authors: Dyafta, Viwe
- Date: 2018
- Subjects: Essences and essential oils Rose geranium oil
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/10747 , vital:35733
- Description: Essential oil of rose scented-geranium is highly versatile and this makes it a very important essential oil in aromatherapy, medicine and cosmetics as well as in flavouring of food and drinks for different industries. The value of the essential oil is directly related to the quality of the oil. Therefore, it is important that the geranium growers take good care of agricultural practices in the production of essential oils as it is a crucial step where oil quality and yield is either obtained or lost. Thus, growing conditions and harvesting time must be cautiously established and controlled including herbage drying to ensure optimum yields and high quality of rose-scented geranium oil. The geranium oil production industry in South Africa is still expanding and oil yield & quality variation is important. This study was undertaken to determine the effects of herbage drying and method, leaf age and paclobutrazol concentrations on oil yield and quality of rose-scented geranium. The responses of oil yield and quality to drying effect was conducted on plant materials which were harvested from the University of Fort Hare Research Farm and glasshouse in December 2014 and October 2015. To determine the effect of drying method on essential oil yield and composition of rose-scented geranium the harvested leaves were dried in direct sunlight (20-35℃) and in a shade conditions (25℃/room temperature). Essential oil was obtained by hydro-distillation using a Clevenger apparatus. The oil samples were analysed by gas chromatography (GC) at the Dohne Agricultural institute. The major components of the oil conducted under the shade method were Linalool (5.58 percent), Menthone (0.68 percent), Citronellol (36.14 percent), Geraniol (7.29 percent), CitronellylFormate (15.39 percent) and GeranylFormate (3.30 percent), whereas those that were sun dried comprised of Linalool (3.56percent), Menthone (0.76 percent), Citronellol (32.25 percent), Geraniol (6.49 percent), CitronellylFormate (14.84 percent) and GeranylFormate (3.15 percent). The analysis of variance showed that freshly dried herbage followed by shade drying is suitable for highest oil yield. In addition, changes in essential oil composition and oil yield with leaf age in rose-scented geranium (Pelargonium capitatum x P. radens cv. Rose) were investigated in a glasshouse of the University of Fort Hare, during January to April and April to August 2012. The plants were allowed to grow to about 12-leaf stage. From top to bottom, the leaves were put into five groups (each group comprising two successive leaves, Pairs 1, 2, 3, 4 and 5). Leaf growth (leaf fresh and dry mass), and essential oil yield and composition data were collected and compared. The results indicated that, leaf fresh and dry mass data were significantly lower in the top-most (youngest leaves) as compared with the rest of the leaf pairs harvested. Essential oil in the youngest leaves was colourless, but as the leaves advanced with age, the oil tended to have a blue-green colour. Oil content (on dry mass basis) from the top to bottom, for Leaf Pairs 1, 2, 3, 4, and 5 were about 7.0, 4.9, 3.2, 2.4, 1.9 percent, respectively. Oil yield showed a significant increase in the second youngest pair of leaves and progressively declined, resulting in a significant lower yield in the oldest leaves. Leaf Pairs 1, 2, 3, 4 and 5, contributed about 19.3, 22.0, 17.71, 12.03 and 8.5 percent of the total yield per branch, respectively. Citronellol:Geraniol ratio was significantly lower in the young leaves than in the old leaves. Linalool and Geranylformate concentrations were the highest in the youngest leaves, and the opposite was observed in isomenthone. Other essential oil components did respond to leaf age. In support of research by Góra et al. (2002), Motsa et al. (2006) and Southwell and Stiff (1989), the current results indicate that early leaf age affects essential oil yield and composition. Thus, shorter regrowth cycles would increase essential oil yield and quality of rose-scented geranium. The paclobutrazol experiment was conducted in a glasshouse at the University of Fort Hare, Alice. A randomized complete block design with four replications was applied. One month after cutting back of the plants, PBZ was applied at the rates of 0, 100, 200 and 300 mg/l on the regrowth and harvested at four months of age. Data, such as chlorophyll content, plant circumference, plant height, fresh and dry mass and oil composition, were determined. The results highlighted that with an increase in PBZ concentration, total herbage mass and plant height tended to decline (Esmaielpour et al., 2011). Thus, in most cases herbage fresh and dry weight of treated plants had lower weight than the control. Paclobutrazol significantly reduced canopy circumference. There was no significant difference (P< 0.05) in oil yield and composition. Furthermore, observations showed that plants receiving PBZ had a deep green colour although the chlorophyll data did not show a significant difference. These results clearly show that PBZ helps geranium plants with compact canopy, which would enable farmers to increase income by increasing planting density, reducing distillation cost of the herbage volume and mass without reducing oil yield per plant. The findings, add another dimension to practical use of this hormone for commercial cultivation.
- Full Text:
- Date Issued: 2018
Stem cutting propagation protocol for rose-scented geranium (Pelargonium graveolens)
- Authors: Matafeni, Ntombekhaya
- Date: 2017
- Subjects: Plant propagation Pelargoniums Plant cuttings
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/9832 , vital:35060
- Description: Rose-scented geranium (Pelargonium graveolens), is a high value essential oil plant that is used in the perfumery, cosmetic, aromatherapy and food flavouring industries. The increasing demand for this plant, due to its economic importance necessitates the development of an efficient propagation protocol for quality seedling and its maximum production. The present study therefore, sought to develop effective stem cutting propagation protocol which could facilitate multiplication of rose-scented geranium stem cuttings. Three separate experiments were undertaken to determine factors influencing effective propagation of rose-scented geranium. These factors were: rooting media, rooting hormone, cutting length and wound healing period on rooting and development of rose-scented geranium stem cuttings. The cuttings were assessed based on root number, length and fresh mass, plant height, leaf number, and stem circumference. In terms of root measurements, the growing media were washed out from the root system of plantlets, their roots were separated from stem before data was recorded which comprised of root number, length and root fresh mass. Root holding ability (RHA) on rooting medium was determined by visual observation and rated on a 1-5 scale where 1 = very loose, not acceptable; 2 = loose, not acceptable; 3 = medium, marginally acceptable; 4 = tight, acceptable; 5 = very tight, acceptable. The experiments were carried out at Essential Amatole Nursery, at the University of Fort Hare Research Farm, Alice Campus (located at 320 47ʹ3ʺS, 260 50ʹ43ʺ E, with an altitude of 519 m.a.s.l). All the experiments were carried out under mist conditions on bottom-heated beds in a greenhouse (with polycarbonate roofing of about 40percent shading effect) for the first three weeks after sticking the cuttings to the growing medium to facilitate root induction in relatively high temperature and relative humidity. Thereafter, the plantlets were grown in a shade house with 70percent light penetration until the termination of the experiment. To optimize the technology for the propagation of this plant the present experiment was designed with the objective to determine the efficient growing medium and proper rooting hormone for successful rooting and development of quality seedlings of rose-scented geranium. The experiment was set up in a complete randomized design (CRD) and was replicated three times with two factors 7×4, seven different growing media i.e. (1) Mixture growing medium which serves as control (pine bark 8 bags + sand 2 bags + lime 4kg + coconut 10 blocks + talborne 6.25 kg + bone meal 2 kg); (2) River sand only; (3) Pine bark; (4) Hygrotex (commercial rooting media); (5) Pine bark + river sand ( at1:1 ratio on volume basis); (6) Pine bark + hygrotex (at 1:1, ratio on volume basis), and; (7) Pine bark + river sand + hygrotex ( at 1:1:1 ratio on volume basis) and four different IBA hormone levels (auxins, types of IBA) applied as treatment were (1) Dynaroot (1 – 1g/kg), (2) Dynaroot (2- 3g/kg), (3) Dynaroot (3-8g/kg) and (4) Control (untreated with hormone). Hygrotex was identified as the best growth media for quicker regeneration giving the highest root number, length and fresh mass. While, hygrotex + pine bark (v/v 1:1) was efficient in producing more leaves, stem circumference and other aerial parameters. Dynaroot 3 was identified as the best rooting enhancer with maximum root number, length, fresh weight and plant height. Both Dynaroot 3 and Dynaroot 2 did not have major differences on giving highest leaf number. Control (untreated with hormone) was consistent in giving the greatest stem circumference than any other treatment. To maximize stem circumference, a combination of control (untreated with hormone) and hygrotex + pine bark (v/v 1:1) was identified as the best treatment. Based on the investigation for maximum production and quality seedlings of rose-scented geranium, hygrotex and Dynaroot 3 were identified as the best combination for successful rooting. The ideal cutting stem length, rooting hormone and growing medium for quality seedlings of rose-scented geranium were also investigated. The experimental lay out was in randomized complete design (RCD) with a 4 × 4 × 2 factorial treatment combination. Treatments used were, four different cutting lengths viz. 10, 12, 14 and 16 cm long; four different concentrations of IBA rooting hormone (Dynaroot 1, 2, 3 (powder form) and distilled water (control) and two types of growing medium (hygrotex and hygrotex + pine bark v/v 1:1) were used. Stem cuttings of 14 and 16 cm length gave the highest root number of 34, 38 and 35.13, and root length of 3.40 and 3.51cm respectively, with no significance. Cutting length of 10 cm favoured stem circumference (3.1 cm) as compared to other treatments. Whereas, cuttings treated with Dynaroot 3 showed a better root number (33.46 roots), root length (3.54 cm), root fresh mass (0.59 mg), leaf number of (11.08) as well as highest root holding ability (5). However, they showed no significance difference with Dynaroot 2 treated cuttings. In addition, cuttings treated with Control favoured shoot number (3.79) and stem circumference (3.05). Visually, hygrotex was observed to be better substrate though it was not significantly different from hygrotex + pine bark (1:1 v/v) on propagation of rose-scented geranium stem cuttings. Therefore, it is recommended that rose-scented geranium should be propagated through the combination of 14 cm cuttings length and treated with Dynaroot 2 IBA rooting hormone. Both hygrotex and hygrotex + pine bark (1:1 v/v) are the best growing media for root formation and growth of rose-scented geranium, though hygrotex alone is more economical. Wound healing period (WHP) of stem cutting was evaluated using 4 × 4 factorial, cuttings were separated into four groups during the healing duration (intervals of 24 hrs: days 0, 1, 2 and 3). These four groups were further subdivided into four subgroups of rooting hormone viz. Dynaroot 1, 2, 3 of indole-3-butyric acid and control (water). Experiment was laid out in a randomised complete block design (RCBD) with three replicates. The results obtained from the study revealed that rose-scented geranium rooted easily when planted on Day 2 of the wound healing period such that root holding ability was at its highest. While, Day 0 cuttings showed good response for stem circumference and shoot number. The study recommends that rose-scented geranium be propagated using cuttings that have enough time to heal the wound that is, Day 2 cuttings. Dynaroot 3 (IBA hormone concentration) showed good response to rooting and other arial parameters except for stem circumference which was favoured by application of control. Based on the results of the study, it can be concluded that propagation of rose-scented geranium requires a wound healing period of about three days in room temperature and application of IBA hormone before sucking cuttings in growing medium. Instead, of Dynaroot 3 or 2, Dynaroot 1 can also be used because, it is less economical and they all have a similar effect on cuttings that have been healing for three days.
- Full Text:
- Date Issued: 2017
- Authors: Matafeni, Ntombekhaya
- Date: 2017
- Subjects: Plant propagation Pelargoniums Plant cuttings
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10353/9832 , vital:35060
- Description: Rose-scented geranium (Pelargonium graveolens), is a high value essential oil plant that is used in the perfumery, cosmetic, aromatherapy and food flavouring industries. The increasing demand for this plant, due to its economic importance necessitates the development of an efficient propagation protocol for quality seedling and its maximum production. The present study therefore, sought to develop effective stem cutting propagation protocol which could facilitate multiplication of rose-scented geranium stem cuttings. Three separate experiments were undertaken to determine factors influencing effective propagation of rose-scented geranium. These factors were: rooting media, rooting hormone, cutting length and wound healing period on rooting and development of rose-scented geranium stem cuttings. The cuttings were assessed based on root number, length and fresh mass, plant height, leaf number, and stem circumference. In terms of root measurements, the growing media were washed out from the root system of plantlets, their roots were separated from stem before data was recorded which comprised of root number, length and root fresh mass. Root holding ability (RHA) on rooting medium was determined by visual observation and rated on a 1-5 scale where 1 = very loose, not acceptable; 2 = loose, not acceptable; 3 = medium, marginally acceptable; 4 = tight, acceptable; 5 = very tight, acceptable. The experiments were carried out at Essential Amatole Nursery, at the University of Fort Hare Research Farm, Alice Campus (located at 320 47ʹ3ʺS, 260 50ʹ43ʺ E, with an altitude of 519 m.a.s.l). All the experiments were carried out under mist conditions on bottom-heated beds in a greenhouse (with polycarbonate roofing of about 40percent shading effect) for the first three weeks after sticking the cuttings to the growing medium to facilitate root induction in relatively high temperature and relative humidity. Thereafter, the plantlets were grown in a shade house with 70percent light penetration until the termination of the experiment. To optimize the technology for the propagation of this plant the present experiment was designed with the objective to determine the efficient growing medium and proper rooting hormone for successful rooting and development of quality seedlings of rose-scented geranium. The experiment was set up in a complete randomized design (CRD) and was replicated three times with two factors 7×4, seven different growing media i.e. (1) Mixture growing medium which serves as control (pine bark 8 bags + sand 2 bags + lime 4kg + coconut 10 blocks + talborne 6.25 kg + bone meal 2 kg); (2) River sand only; (3) Pine bark; (4) Hygrotex (commercial rooting media); (5) Pine bark + river sand ( at1:1 ratio on volume basis); (6) Pine bark + hygrotex (at 1:1, ratio on volume basis), and; (7) Pine bark + river sand + hygrotex ( at 1:1:1 ratio on volume basis) and four different IBA hormone levels (auxins, types of IBA) applied as treatment were (1) Dynaroot (1 – 1g/kg), (2) Dynaroot (2- 3g/kg), (3) Dynaroot (3-8g/kg) and (4) Control (untreated with hormone). Hygrotex was identified as the best growth media for quicker regeneration giving the highest root number, length and fresh mass. While, hygrotex + pine bark (v/v 1:1) was efficient in producing more leaves, stem circumference and other aerial parameters. Dynaroot 3 was identified as the best rooting enhancer with maximum root number, length, fresh weight and plant height. Both Dynaroot 3 and Dynaroot 2 did not have major differences on giving highest leaf number. Control (untreated with hormone) was consistent in giving the greatest stem circumference than any other treatment. To maximize stem circumference, a combination of control (untreated with hormone) and hygrotex + pine bark (v/v 1:1) was identified as the best treatment. Based on the investigation for maximum production and quality seedlings of rose-scented geranium, hygrotex and Dynaroot 3 were identified as the best combination for successful rooting. The ideal cutting stem length, rooting hormone and growing medium for quality seedlings of rose-scented geranium were also investigated. The experimental lay out was in randomized complete design (RCD) with a 4 × 4 × 2 factorial treatment combination. Treatments used were, four different cutting lengths viz. 10, 12, 14 and 16 cm long; four different concentrations of IBA rooting hormone (Dynaroot 1, 2, 3 (powder form) and distilled water (control) and two types of growing medium (hygrotex and hygrotex + pine bark v/v 1:1) were used. Stem cuttings of 14 and 16 cm length gave the highest root number of 34, 38 and 35.13, and root length of 3.40 and 3.51cm respectively, with no significance. Cutting length of 10 cm favoured stem circumference (3.1 cm) as compared to other treatments. Whereas, cuttings treated with Dynaroot 3 showed a better root number (33.46 roots), root length (3.54 cm), root fresh mass (0.59 mg), leaf number of (11.08) as well as highest root holding ability (5). However, they showed no significance difference with Dynaroot 2 treated cuttings. In addition, cuttings treated with Control favoured shoot number (3.79) and stem circumference (3.05). Visually, hygrotex was observed to be better substrate though it was not significantly different from hygrotex + pine bark (1:1 v/v) on propagation of rose-scented geranium stem cuttings. Therefore, it is recommended that rose-scented geranium should be propagated through the combination of 14 cm cuttings length and treated with Dynaroot 2 IBA rooting hormone. Both hygrotex and hygrotex + pine bark (1:1 v/v) are the best growing media for root formation and growth of rose-scented geranium, though hygrotex alone is more economical. Wound healing period (WHP) of stem cutting was evaluated using 4 × 4 factorial, cuttings were separated into four groups during the healing duration (intervals of 24 hrs: days 0, 1, 2 and 3). These four groups were further subdivided into four subgroups of rooting hormone viz. Dynaroot 1, 2, 3 of indole-3-butyric acid and control (water). Experiment was laid out in a randomised complete block design (RCBD) with three replicates. The results obtained from the study revealed that rose-scented geranium rooted easily when planted on Day 2 of the wound healing period such that root holding ability was at its highest. While, Day 0 cuttings showed good response for stem circumference and shoot number. The study recommends that rose-scented geranium be propagated using cuttings that have enough time to heal the wound that is, Day 2 cuttings. Dynaroot 3 (IBA hormone concentration) showed good response to rooting and other arial parameters except for stem circumference which was favoured by application of control. Based on the results of the study, it can be concluded that propagation of rose-scented geranium requires a wound healing period of about three days in room temperature and application of IBA hormone before sucking cuttings in growing medium. Instead, of Dynaroot 3 or 2, Dynaroot 1 can also be used because, it is less economical and they all have a similar effect on cuttings that have been healing for three days.
- Full Text:
- Date Issued: 2017
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