MENVSC (Geography) / Department of Geography and Geo-Information Sciences / Climate variability and change directly affect agricultural production. This is because the agricultural sector is inherently sensitive to climatic conditions and is one of the most vulnerable sectors to risks and impact of global climate change. The aim of this study was to determine maize producer's vulnerability and assess the impact of climate variability and change on maize production in the Makhuduthamaga Local Municipality, of Limpopo Province, South Africa. Climatic and maize yields data utilized in the study are for the period 1985 - 2015). Interviews were also conducted with the producers and various officials from government and non-governmental sectors. The results illustrate significant rainfall and temperature variations both spatially and temporally. The variations observed in the average rainfall and rain days for the period under consideration were not related to the variation in yield of maize for the same period. The regression results revealed low R² values, indicating a weak relationship between maize yields, rain days and rainfall. Furthermore, the results revealed a significant positive relationship between annual rainfall and temperature (r²<0.05 and P<0.05) but not a significant relationship with maize yields. The results of the qualitative data showed that the producers’ perception of the occurrence of climate variability was high, as 65.7% of the respondents indicated that the state of climate is increasingly variable. About 61.5% of the producers implemented or adopted an adaptation strategy to cope with the perceived climate variability and change. Age, gender and access to extension services were determined as important factors that determine the adoption of adaptation strategies. The vulnerability assessment revealed that producers were highly vulnerable to changing climate; this exposes producers to the risks of crop failure, loss of income and food insecurity. The study recommended (a) intervention and adaptation strategies that target mitigation of decreased rainfall impacts (b) increased access to extension service (c) empirical research around the impacts of climate change to increase producers’ level of awareness. / NRF

MSCAGR (Plant Production) / Department of Plant Production / Smallholder farmers in Sub-Saharan Africa still obtain low grain yields in maize largely due to low soil fertility. The soils are inherently low in nitrogen (N) that is required for the proper development of the maize plant. Currently there are no commercial cultivars for low N tolerance locally. The combining ability approach can be used as a tool for breeding desirable cultivars. In order to improve grain yield in maize, it is important to consider ear prolificacy which is a major yield component. Therefore this study was designed to estimate combining ability in maize. Exotic germplasm from the International Maize and Wheat Improvement Center and the Institute of Tropical Agriculture as well as the local germplasm from the Agricultural Research Council was used in the study to generate crosses. One hundred and two crosses were evaluated together with a standard commercial check under low N and optimum N conditions. The specific objectives of the study were to determine general and specific combining ability for prolificacy among local and exotic inbred lines and evaluate the response of prolific hybrids to low N conditions. The hybrids were planted in the 2014/2015 summer season under irrigation in Potchefstroom, Cedara and Taung in field plots consisting of 0.75m x 0.25m spacing in a 0.1 alpha lattice design replicated twice. Data for agronomic attributes were recorded and subjected to analysis of variance using SAS version 9.1.3. Genetic correlations were analyzed using the Principal Components Analysis and factor analysis based on the correlation analysis and major traits. The results showed variation in agronomic performance among the inbred lines and their F1 hybrids. Inbred lines including TZEI63, T1162W, L15 and L17 showed positive GCA estimates for ear prolificacy at the different locations. Specific combining ability for prolific hybrids was positive at all locations and environments. The GCA:SCA ratio was close to unity; indicating that the number of ears per plant showed highly significant (P<0.01) correlation with grain yield. The hybrids showed ear prolificacy under the low N conditions. This trait can be used effectively in stress tolerance maize breeding programmes. / NRF