- Title
- An evaluation of stress tolerant open pollinated maize varieties in selected environments of the Eastern Cape Province, South Africa
- Creator
- Chimonyo, Vimbayi G P https://orcid.org/0000-0001-9912-9848
- Subject
- Crops -- Effect of stress on
- Date
- 2011-11
- Type
- Master's theses
- Type
- text
- Identifier
- http://hdl.handle.net/10353/24487
- Identifier
- vital:63045
- Description
- The use of farmer acceptable, stress tolerant open pollinated maize varieties (OPVs) could be a strategy to help increase maize productivity for resource-poor farmers in the Eastern Cape (EC) Province. The current study investigated the following: a) participatory selection of newly introduced stress tolerant maize OPVs; b) characteristics of maize producing farmers, their production constraints and criteria for variety selections; c) multi-environment yield trials in which genotype and environment interactions (GEI) were investigated, and d) morphological diversity of newly introduced maize varieties. Nine newly introduced maize OPVs were evaluated in this study. These varieties were: ZM 305, ZM 423 ZM 501, ZM 525, Obatanpa, ZM 621, ZM 627, which were from the International Maize and Wheat Improvement Centre (CIMMYT), BR 993, and Comp 4 which from where the International Institute of Tropical Agriculture (IITA). Check varieties, Pan 6479 (a hybrid) and three locally grown OPVs (Okavango, Afric 1 and Nelson‘s Choice) were also included. Participatory variety selection (PVS) was conducted during the 2009/10 summer season to evaluate farmer acceptance of these newly introduced OPVs. The most preferred varieties farmers were Okavango, ZM 305 and ZM 501, and these varieties were not significantly different from the highest yielding variety within each site. Therefore, varieties like ZM 305 and ZM 501 could easily be adopted by farmers, and their use could result in yield improvements. To gather information on farmer characteristics, and perceptions on maize production constraints and maize selection criteria, focus group discussions and household surveys were conducted during the 2009/2010 and 2010/2011 seasons, respectively. Results indicated that, elderly farmers dominated the farming communities. Maize production was generally low, with 98percent of the farmers obtaining less than 1.6 t/ha. The most important constraints affecting maize production were extreme weather events (floods and drought), pests and diseases, and poor access to credit. The most preferred traits that made up farmer selection criteria were ear traits such as taste, long cobs, and big kernels. Other traits, such as, prolificacy, early maturity, retainability of seed and dark leaves, were village specific. Yield trials, assessing genotype and environment interactions, were conducted in eight sites during the 2009/10 and 2010/11 seasons. The genotypes exhibited non-significant crossover and non-crossover GEI over the environments. Okavango, the most stable variety, was generally low yielding (4.28 t/ha) than other stable varieties such as ZM 305, ZM 501, ZM 621 and ZM 423. The later varieties had significantly (p<0.05) higher yields of between 4.46 t/ha and 4.97 t/ha. The highest yielding varieties, Pan 6479 (5.29 t/ha) and ZM 525 (4.87 t/ha), showed specific adaptations to high potential environments, while BR 993 (4.07 t/ha) and Afric 1 (4.24 t/ha) were low yielding, unstable and specifically adapted to low potential environments. New varieties, therefore, exhibited both specific and wide adaptation. Qualitative and quantitative traits were evaluated to establish the morphological diversity of the 13 varieties. Ear height, plant height, days to 50percent anthesis and grain yield contributed the most to variety diversity. Cluster Analysis discriminated varieties into four main clusters. The first cluster consisted of four CIMMYT varieties that were short in height and early maturing (ZM 305, ZM 423, ZM 501 and ZM 525), while hybrid Pan 6479 was placed into cluster two. Nelson‘s Choice and Okavango were grouped into the third cluster, while tall and late maturing varieties, ZM 621, ZM 627, Obatanpa, BR 993, Comp 4 and Afric 1, were placed in the fourth cluster. The segregation of the newly introduced varieties into two distinct groups shows that these varieties can be recommended into more than on cropping system and agro-ecology. Differences in village agro-ecologies resulted in farmers selecting varieties differently. This diversity in agro-ecology also brought about variations on farmer perceptions in selection criteria and production constraints. Most of the new varieties were observed to be superior in yield performance when compared to local check OPVs, exhibiting either wide or specific adaptation. The study also demonstrated that, the study of morphological diversity can be used to suggest varieties to different environmental potentials and cropping systems. Multi-evaluation trials were able to give an insight on variety preferences and performance. These new varieties should, therefore, be introduced to selected farmers living in their respective environments on the basis of results obtained. However, varieties still need to be evaluated under farmer-managed conditions to determine whether they actually bring about yield improvement when compared with current varieties being used.
- Description
- Thesis (MSc) -- Faculty of Science and Agriculture, 2011
- Format
- computer
- Format
- online resource
- Format
- application/pdf
- Format
- 1 online resource (175 leaves)
- Format
- Publisher
- University of Fort Hare
- Publisher
- Faculty of Science and Agriculture
- Language
- English
- Rights
- University of Fort Hare
- Rights
- All Rights Reserved
- Rights
- Open Access
- Hits: 263
- Visitors: 280
- Downloads: 29
Collections
UFH Department of Agronomy
| Thumbnail | File | Description | Size | Format | |||
|---|---|---|---|---|---|---|---|
| View Details | SOURCE1 | M Sc Agric (May 2012) CHIMONYO.pdf | 1 MB | Adobe Acrobat PDF | View Details |