Evaluation of the possible application of cowpea genotypes in the farming systems of the Eastern Cape Province, South Africa
- Authors: Adeyemi, Samson Adebowale
- Date: 2012
- Subjects: Cowpea -- South Africa -- Eastern Cape , Cowpea , Plant diversity , Cowpea -- Genetics , DNA fingerprinting of plants
- Language: English
- Type: Thesis , Masters , MSc (Biochemistry)
- Identifier: vital:11274 , http://hdl.handle.net/10353/d1007539 , Cowpea -- South Africa -- Eastern Cape , Cowpea , Plant diversity , Cowpea -- Genetics , DNA fingerprinting of plants
- Description: Characterization studies on the genetic diversity among cultivated cowpea (Vigna unguiculata (L.) varieties are valuable tools to optimize the use of available genetic resources by farmers, local communities, researchers and breeders. Eight cowpea (Vigna unguiculata (L.) genotypes ( Vegetable cowpea, Ivory grey, Okhalweni, Fahari, Fahari dark, 97K-1069-8, IT93K-73h, and 129-3) were subjected to molecular, morphological and agronomical characterization. DNA amplification fingerprinting markers were used to evaluate the genetic diversity among the eight genotypes. Nine random arbitrary primers were used to screen the eight genotypes to assess their ability to reveal polymorphisms in cowpea, and seven of them were selected for use in characterizing the total sample. A total of 43 bands were generated which are all polymorphic. On the average, the primers generated a total of 6.1 polymorphic bands. The resulting data-matrix included 43 analysed bands with a total of 344 characters. Neighbour joining analysis was used to generate the dendrogram, clustering the genotypes into two groups at an agglomerate coefficient of 0.30 irrespective of their geographical origins. The results also showed the presence of significant differences in morphological and quality traits among the genotypes. Fahari yielded the highest concentration of crude protein (46.51 mg/mg dry leaf) while Vegetable cowpea yielded the lowest (24.41 mg/mg dry leaf). The influence of manure was also found to be effective by increasing the crude protein content of the genotypes as shown by Fahari dark with an average of 53.53 mg/mg dry leaf as opposed to 39.85 mg/mg dry leaf without manure application. Although some small clusters grouped accessions of the same growth habits, a general lack of agreement between clustering and morphological features was observed. It can therefore be concluded that the significant differences between the molecular genetic analysis using DAF-PCR markers, morphologic characters and yield traits can be important tools to identify and discriminates the different cowpea genotypes.
- Full Text:
- Date Issued: 2012
- Authors: Adeyemi, Samson Adebowale
- Date: 2012
- Subjects: Cowpea -- South Africa -- Eastern Cape , Cowpea , Plant diversity , Cowpea -- Genetics , DNA fingerprinting of plants
- Language: English
- Type: Thesis , Masters , MSc (Biochemistry)
- Identifier: vital:11274 , http://hdl.handle.net/10353/d1007539 , Cowpea -- South Africa -- Eastern Cape , Cowpea , Plant diversity , Cowpea -- Genetics , DNA fingerprinting of plants
- Description: Characterization studies on the genetic diversity among cultivated cowpea (Vigna unguiculata (L.) varieties are valuable tools to optimize the use of available genetic resources by farmers, local communities, researchers and breeders. Eight cowpea (Vigna unguiculata (L.) genotypes ( Vegetable cowpea, Ivory grey, Okhalweni, Fahari, Fahari dark, 97K-1069-8, IT93K-73h, and 129-3) were subjected to molecular, morphological and agronomical characterization. DNA amplification fingerprinting markers were used to evaluate the genetic diversity among the eight genotypes. Nine random arbitrary primers were used to screen the eight genotypes to assess their ability to reveal polymorphisms in cowpea, and seven of them were selected for use in characterizing the total sample. A total of 43 bands were generated which are all polymorphic. On the average, the primers generated a total of 6.1 polymorphic bands. The resulting data-matrix included 43 analysed bands with a total of 344 characters. Neighbour joining analysis was used to generate the dendrogram, clustering the genotypes into two groups at an agglomerate coefficient of 0.30 irrespective of their geographical origins. The results also showed the presence of significant differences in morphological and quality traits among the genotypes. Fahari yielded the highest concentration of crude protein (46.51 mg/mg dry leaf) while Vegetable cowpea yielded the lowest (24.41 mg/mg dry leaf). The influence of manure was also found to be effective by increasing the crude protein content of the genotypes as shown by Fahari dark with an average of 53.53 mg/mg dry leaf as opposed to 39.85 mg/mg dry leaf without manure application. Although some small clusters grouped accessions of the same growth habits, a general lack of agreement between clustering and morphological features was observed. It can therefore be concluded that the significant differences between the molecular genetic analysis using DAF-PCR markers, morphologic characters and yield traits can be important tools to identify and discriminates the different cowpea genotypes.
- Full Text:
- Date Issued: 2012
Inhibitory potential of honey on the enzymatic activity of Helicobacter pylori urease
- Authors: Matongo, Fredrick
- Date: 2012
- Subjects: Honey , Helicobacter pylori infections , Enzyme inhibitors , Traditional medicine , Antifungal agents
- Language: English
- Type: Thesis , Masters , MSc (Biochemistry)
- Identifier: vital:11253 , http://hdl.handle.net/10353/431 , Honey , Helicobacter pylori infections , Enzyme inhibitors , Traditional medicine , Antifungal agents
- Description: Urease of Helicobacter pylori is an important virulence factor implicated in the pathogenesis of many clinical conditions, such as chronic gastritis, peptic ulceration, and gastric cancer. Many urease inhibitors have been discovered, like phosphorodiamidates, hydroxamic acid derivatives, and imidazoles. Despite good activities at the enzyme level and excellent kinetic properties most of them have not been used as therapeutic agents in vivo because of their side effects, toxicity and instability. This has led to much attention to focus on exploring the novel urease inhibitory activities of natural products because of their low toxicity and good bioavailability. Honey, a natural product has been used in folk medicine due to its antitumor, antioxidant, antimicrobial and anti-inflammatory properties. The aims of this study were to isolate, characterise, purify urease produced by H. pylori and investigate the inhibitory effects of solvent honey extracts on its enzymatic activity. Urease was found to be both surface-associated and cytoplasmic. Maximum cytoplasmic urease activity was found to occur after 72 hr whereas maximum extracellular urease activities were found to occur after 96 hr. Characterization of the crude cytoplasmic urease revealed optimal activity at a pH of 7.5 and temperature of 40°C. The kinetic parameters Vmax and Km were 45.32 U ml-1 and 61.11 mM respectively.The honey extracts inhibited the activity of the crude urease in a concentration dependent manner. The Lineweaver-Burk plots indicated a non-competitive type of inhibition against H. pylori urease. The two honey extracts gave promising inhibitory activities against urease of H. pylori. Thus the results of this study delineates that inhibition of urease can ease development in therapeutic and preventative approaches based on the enzymatic activity of this Helicobacter protein.
- Full Text:
- Date Issued: 2012
- Authors: Matongo, Fredrick
- Date: 2012
- Subjects: Honey , Helicobacter pylori infections , Enzyme inhibitors , Traditional medicine , Antifungal agents
- Language: English
- Type: Thesis , Masters , MSc (Biochemistry)
- Identifier: vital:11253 , http://hdl.handle.net/10353/431 , Honey , Helicobacter pylori infections , Enzyme inhibitors , Traditional medicine , Antifungal agents
- Description: Urease of Helicobacter pylori is an important virulence factor implicated in the pathogenesis of many clinical conditions, such as chronic gastritis, peptic ulceration, and gastric cancer. Many urease inhibitors have been discovered, like phosphorodiamidates, hydroxamic acid derivatives, and imidazoles. Despite good activities at the enzyme level and excellent kinetic properties most of them have not been used as therapeutic agents in vivo because of their side effects, toxicity and instability. This has led to much attention to focus on exploring the novel urease inhibitory activities of natural products because of their low toxicity and good bioavailability. Honey, a natural product has been used in folk medicine due to its antitumor, antioxidant, antimicrobial and anti-inflammatory properties. The aims of this study were to isolate, characterise, purify urease produced by H. pylori and investigate the inhibitory effects of solvent honey extracts on its enzymatic activity. Urease was found to be both surface-associated and cytoplasmic. Maximum cytoplasmic urease activity was found to occur after 72 hr whereas maximum extracellular urease activities were found to occur after 96 hr. Characterization of the crude cytoplasmic urease revealed optimal activity at a pH of 7.5 and temperature of 40°C. The kinetic parameters Vmax and Km were 45.32 U ml-1 and 61.11 mM respectively.The honey extracts inhibited the activity of the crude urease in a concentration dependent manner. The Lineweaver-Burk plots indicated a non-competitive type of inhibition against H. pylori urease. The two honey extracts gave promising inhibitory activities against urease of H. pylori. Thus the results of this study delineates that inhibition of urease can ease development in therapeutic and preventative approaches based on the enzymatic activity of this Helicobacter protein.
- Full Text:
- Date Issued: 2012
Parent characterization of quality protein maize (Zea mays L.) and combining ability for tolerance to drought stress
- Authors: Pfunde, Cleopatra Nyaradzo
- Date: 2012
- Subjects: Corn -- Quality , Corn as food , Corn -- Effect of stress on , Corn -- Effect of drought on , Cluster analysis , Crops -- Effect of drought on , Corn -- Drought tolerance , Corn -- Breeding , Crops -- Drought tolerance
- Language: English
- Type: Thesis , Masters , MSc Agric (Crop Science)
- Identifier: vital:11869 , http://hdl.handle.net/10353/d1007536 , Corn -- Quality , Corn as food , Corn -- Effect of stress on , Corn -- Effect of drought on , Cluster analysis , Crops -- Effect of drought on , Corn -- Drought tolerance , Corn -- Breeding , Crops -- Drought tolerance
- Description: Quality protein maize (QPM) has enhanced levels of two essential amino acids, lysine and tryptophan compared to normal maize. This makes QPM an important cereal crop in communities where maize is a staple crop. The main abiotic factor to QPM production is drought stress. Little information is available on the effect of drought stress on QPM. Therefore, the objectives of this study were to: (i) conduct diversity analysis of QPM inbred lines using morpho-agronomic and simple sequence repeat markers, (ii) screen available QPM inbred lines and F1 progeny for tolerance to seedling drought stress, (iii) determine the combining ability and type of gene action of QPM inbred lines for tolerance to seedling drought stress, grain yield and endosperm modification. The study was conducted in South Africa, at the University of Fort Hare. Morphological characterisation of 21 inbred lines was done using quantitative and qualitative traits. A randomised complete block design with three replicates was used for characterizing the inbred lines in the field. Genstat statistical software, version 12 (Genstat ®, 2009) was used for analysis of variance (ANOVA) and descriptive statistics. Analysis of variance was performed on all quantitative data for morphological traits. Data for qualitative traits was tabulated in their nominal classes. Traits that contributed most to the variation were days to anthesis, days to silking, anthesis-silking interval, plant height, number of kernel rows, ear length and grain yield. Cluster analysis grouped the inbred lines into three main clusters. The first cluster was characterised by tall and average yielding lines, while the second cluster showed the least anthesis-silking interval, and had the highest yield. Cluster three consisted of lines that were early maturing, but were the least yielding. Genetic distances between maize inbred lines were quantified by using 27 simple sequence repeat markers. The genetic distances between genotypes was computed using Roger’s (1972) genetic distances. Cluster analysis was then carried out using the neighbour-joining tree method using Power Marker software version 3.25. A dendrogram generated from the genetic study of the inbred lines revealed three groups that concurred with expectations based upon pedigree data. These groups were not identical to the groups generated using morpho-agronomic characterisation. Twenty one QPM inbred lines were crossed using a North Carolina design II mating scheme. These were divided into seven sets, each with three inbred lines. The three inbred lines in one set were used as females and crossed with three inbred lines in another set consisting of males. Each inbred line was used as a female in one set, and as a male in a second set. Sixty three hybrids (7 sets x 9 hybrids) were formed and evaluated in October 2011, using a 6x8 alpha-lattice incomplete block design with three replicates under glasshouse and optimum field conditions. A randomised complete block design with three replicates was used for the 21 parental inbred lines. Traits recorded for the glasshouse study were, canopy temperature, chlorophyll content, leaf roll, stem diameter, plant height, leaf number, leaf area, fresh and dry root and shoot weights. Data for the various traits for each environment, 25 percent (stress treatment) and 75 percent (non-stress) of field capacity, were subjected to analysis of variance using the unbalanced treatment design in Genstat statistical package Edition 12. Where varietal differences were found, means were separated using Tukey’s test. Genetic analyses for grain yield and agronomic traits were performed using a fixed effects model in JMP 10 following Residual Maximum Likelihood procedure (REML). From the results, inbred lines that were not previously classified into heterotic groups and drought tolerance categories were classified based on their total dry weight performance and drought susceptibility index. Inbred lines L18, L9, L8, L6 and L3, in order of their drought tolerance index were the best performers under greenhouse conditions and could be recommended for breeding new varieties that are tolerant to seedling drought stress. Evaluation of maize seedlings tolerant to drought stress under glasshouse conditions revealed that cross combination L18 x L11 was drought tolerant, while cross L20 x L7 was susceptible. Total dry weight was used as the major criteria for classifying F1 maize seedlings as being resistant or susceptible. General combining ability effects accounted for 67.43 percent of the genetic variation for total dry weight, while specific combining ability effects contributed 37.57 percent. This indicated that additive gene effects were more important than non-additive gene action in controlling this trait. In the field study (non-drought), the experimental design was a 6x8 alpha lattice incomplete block design with three replicates. On an adjacent field a randomised complete block design with three replicates was used to evaluate the parental inbred lines. The following variables were recorded: plant height, ear height, ears per plant, endosperm modification, days to silking and days to anthesis, anthesis-silking interval, number of kernels per row, number of rows per ear and grain yield. General analyses for the incomplete lattice block design and randomised complete block design for hybrid and inbred data respectively were performed using JMP 10 statistical software. Means were separated using the Tukey's test. Genetic analyses of data for grain yield and agronomic traits were conducted using a fixed effects model using REML in JMP 10. The importance of both GCA (51 percent) and SCA (49 percent) was observed for grain yield. A preponderance of GCA existed for ear height, days to anthesis, anthesis-silking interval, ears per plant and number of kernels per row, indicating that predominantly, additive gene effects controlled hybrid performance under optimum field conditions. The highest heritability was observed for days to silking (48.27 percent) suggesting that yield could be improved through selection for this trait. Under field conditions, variation in time to maturity was observed. This implies that these inbred lines can be recommended for utilisation in different agro-ecologies. Early maturing lines such as L18 can be used to introduce earliness in local cultivars, while early maturing single crosses such as L18 x L2, L5 x L9, L3 x L4 and L2 x L21 could be recommended for maize growers in drought prone areas such as the former Ciskei. Single crosses L18xL11, L16xL18, L8xL21 and L9xL6 had good tolerance to seedling drought stress. On the other hand, single crosses L18xL11 and L11xL13 had high grain yield and good endosperm modification. All these single crosses could be recommended for commercial production after evaluation across locations in the Eastern Cape Province. Alternatively they can be crossed with other superior inbreds to generate three or four way hybrids, which could then be evaluated for potential use by farmers in the Eastern Cape.
- Full Text:
- Date Issued: 2012
- Authors: Pfunde, Cleopatra Nyaradzo
- Date: 2012
- Subjects: Corn -- Quality , Corn as food , Corn -- Effect of stress on , Corn -- Effect of drought on , Cluster analysis , Crops -- Effect of drought on , Corn -- Drought tolerance , Corn -- Breeding , Crops -- Drought tolerance
- Language: English
- Type: Thesis , Masters , MSc Agric (Crop Science)
- Identifier: vital:11869 , http://hdl.handle.net/10353/d1007536 , Corn -- Quality , Corn as food , Corn -- Effect of stress on , Corn -- Effect of drought on , Cluster analysis , Crops -- Effect of drought on , Corn -- Drought tolerance , Corn -- Breeding , Crops -- Drought tolerance
- Description: Quality protein maize (QPM) has enhanced levels of two essential amino acids, lysine and tryptophan compared to normal maize. This makes QPM an important cereal crop in communities where maize is a staple crop. The main abiotic factor to QPM production is drought stress. Little information is available on the effect of drought stress on QPM. Therefore, the objectives of this study were to: (i) conduct diversity analysis of QPM inbred lines using morpho-agronomic and simple sequence repeat markers, (ii) screen available QPM inbred lines and F1 progeny for tolerance to seedling drought stress, (iii) determine the combining ability and type of gene action of QPM inbred lines for tolerance to seedling drought stress, grain yield and endosperm modification. The study was conducted in South Africa, at the University of Fort Hare. Morphological characterisation of 21 inbred lines was done using quantitative and qualitative traits. A randomised complete block design with three replicates was used for characterizing the inbred lines in the field. Genstat statistical software, version 12 (Genstat ®, 2009) was used for analysis of variance (ANOVA) and descriptive statistics. Analysis of variance was performed on all quantitative data for morphological traits. Data for qualitative traits was tabulated in their nominal classes. Traits that contributed most to the variation were days to anthesis, days to silking, anthesis-silking interval, plant height, number of kernel rows, ear length and grain yield. Cluster analysis grouped the inbred lines into three main clusters. The first cluster was characterised by tall and average yielding lines, while the second cluster showed the least anthesis-silking interval, and had the highest yield. Cluster three consisted of lines that were early maturing, but were the least yielding. Genetic distances between maize inbred lines were quantified by using 27 simple sequence repeat markers. The genetic distances between genotypes was computed using Roger’s (1972) genetic distances. Cluster analysis was then carried out using the neighbour-joining tree method using Power Marker software version 3.25. A dendrogram generated from the genetic study of the inbred lines revealed three groups that concurred with expectations based upon pedigree data. These groups were not identical to the groups generated using morpho-agronomic characterisation. Twenty one QPM inbred lines were crossed using a North Carolina design II mating scheme. These were divided into seven sets, each with three inbred lines. The three inbred lines in one set were used as females and crossed with three inbred lines in another set consisting of males. Each inbred line was used as a female in one set, and as a male in a second set. Sixty three hybrids (7 sets x 9 hybrids) were formed and evaluated in October 2011, using a 6x8 alpha-lattice incomplete block design with three replicates under glasshouse and optimum field conditions. A randomised complete block design with three replicates was used for the 21 parental inbred lines. Traits recorded for the glasshouse study were, canopy temperature, chlorophyll content, leaf roll, stem diameter, plant height, leaf number, leaf area, fresh and dry root and shoot weights. Data for the various traits for each environment, 25 percent (stress treatment) and 75 percent (non-stress) of field capacity, were subjected to analysis of variance using the unbalanced treatment design in Genstat statistical package Edition 12. Where varietal differences were found, means were separated using Tukey’s test. Genetic analyses for grain yield and agronomic traits were performed using a fixed effects model in JMP 10 following Residual Maximum Likelihood procedure (REML). From the results, inbred lines that were not previously classified into heterotic groups and drought tolerance categories were classified based on their total dry weight performance and drought susceptibility index. Inbred lines L18, L9, L8, L6 and L3, in order of their drought tolerance index were the best performers under greenhouse conditions and could be recommended for breeding new varieties that are tolerant to seedling drought stress. Evaluation of maize seedlings tolerant to drought stress under glasshouse conditions revealed that cross combination L18 x L11 was drought tolerant, while cross L20 x L7 was susceptible. Total dry weight was used as the major criteria for classifying F1 maize seedlings as being resistant or susceptible. General combining ability effects accounted for 67.43 percent of the genetic variation for total dry weight, while specific combining ability effects contributed 37.57 percent. This indicated that additive gene effects were more important than non-additive gene action in controlling this trait. In the field study (non-drought), the experimental design was a 6x8 alpha lattice incomplete block design with three replicates. On an adjacent field a randomised complete block design with three replicates was used to evaluate the parental inbred lines. The following variables were recorded: plant height, ear height, ears per plant, endosperm modification, days to silking and days to anthesis, anthesis-silking interval, number of kernels per row, number of rows per ear and grain yield. General analyses for the incomplete lattice block design and randomised complete block design for hybrid and inbred data respectively were performed using JMP 10 statistical software. Means were separated using the Tukey's test. Genetic analyses of data for grain yield and agronomic traits were conducted using a fixed effects model using REML in JMP 10. The importance of both GCA (51 percent) and SCA (49 percent) was observed for grain yield. A preponderance of GCA existed for ear height, days to anthesis, anthesis-silking interval, ears per plant and number of kernels per row, indicating that predominantly, additive gene effects controlled hybrid performance under optimum field conditions. The highest heritability was observed for days to silking (48.27 percent) suggesting that yield could be improved through selection for this trait. Under field conditions, variation in time to maturity was observed. This implies that these inbred lines can be recommended for utilisation in different agro-ecologies. Early maturing lines such as L18 can be used to introduce earliness in local cultivars, while early maturing single crosses such as L18 x L2, L5 x L9, L3 x L4 and L2 x L21 could be recommended for maize growers in drought prone areas such as the former Ciskei. Single crosses L18xL11, L16xL18, L8xL21 and L9xL6 had good tolerance to seedling drought stress. On the other hand, single crosses L18xL11 and L11xL13 had high grain yield and good endosperm modification. All these single crosses could be recommended for commercial production after evaluation across locations in the Eastern Cape Province. Alternatively they can be crossed with other superior inbreds to generate three or four way hybrids, which could then be evaluated for potential use by farmers in the Eastern Cape.
- Full Text:
- Date Issued: 2012
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