Research Journal of Agriculture and Biological Sciences, 5(3): 287-292, 2009 © 2009, INSInet Publication Corresponding Author: Itai Makanda, African Centre for Crop Improvement, University of KwaZulu-Natal, P/Bag X01 Scottsville, South Africa 287 Path Coefficient Analysis of Bambara Groundnut Pod Yield Components at Four Planting Dates Itai Makanda, Pangirayi Tongoona, Rosalia Madamba, David Icishahayo and John Derera 1 1 2 3 1 African Centre for Crop Improvement, University of KwaZulu-Natal, P/Bag X01 Scottsville, 1 South Africa Crop Breeding Institute, P. O. Box CY550 Causeway, Harare, Zimbabwe 2 Department of Crop Science, University of Zimbabwe P.O. Box MP167 Mt Pleasant, 3 Harare, Zimbabwe Abstract: Little is known on the relationship between yield and its components in bambara groundnuts outside the traditional growing season in Zimbabwe, information that is important when selecting cultivars for off-season planting. To study these relationships, correlation and path coefficient analyses were performed on yield traits in bambara groundnuts cultivars planted at four planting dates in Zimbabwe during 2000 – 2001. A split-plot arrangement in a randomised complete block design with planting date as main plot factor and cultivar as subplot factor was used. Moisture was supplied through irrigation during off-season cultivation and supplementary irrigation was applied during the rainy season. Days to 50% emergence, days to 50% flowering, days to 95% physiological maturity, plant count at harvest, pod count plant , and dry pod yield plot were measured and data were analysed using GenStat. Correlation -1 -1 and path coefficient analyses were performed for the traits for each planting date. Most of the correlation coefficients were significant (P<0.05) and dry pod yield was more dependent on the direct effects of its components compared to the indirect effects through other components, suggesting that direct selection is more effective. All the direct effects showed contrasting influences on dry pod yield for the same traits, but at different planting dates except for the number of plants plot on which they were all positive. The -1 contrast could be attributed to different photothermal conditions between the growing conditions associated with the planting dates. Indirect effects through number of plants plot were high, suggesting the -1 possibility of correlated response in selection. The experiment showed plant establishment and number of pods plant to be the important traits in bambara cultivar development. -1 Key words: Bambara groundnut, correlation, path coefficients INTRODUCTION Little information on bambara groundnut research and cultivar development is available, although there is a shift in the crop’s importance from a subsistence crop to a commercial crop. It is now canned in the same way as beans, peas and maize and its market value has increased. More farmers are now starting to grow the crop and an early crop fetches a high market price compared to a normal season crop. It also escapes foliar diseases associated with increased humidity at favourable temperatures during the main rainy season as reported for Ascochyta blight on chickpea . There are no suitable varieties for early [1,2] planting in Zimbabwe. Farmers are therefore at risk when unsuitable cultivars are planted early so as to have a competitive edge on the market. This emphasises the need to develop cultivars for off-season planting to meet the farmers’ needs. Cultivar development requires an understanding of the responses and relationships between yield-determining traits under the conditions in which the cultivars are to be deployed. Such relationships have been studied using correlation coefficients. Correlation coefficients alone may still not be reliable in selection as they represent simple linear relationships between traits . [3] Further studies have used non-linear connecting paths of influence between traits through further breaking down of correlation coefficients . These [3] influences have been termed path coefficients attributable to direct and indirect causes . Path [3,4] coefficients give the relative contribution of various yield-determining traits, enabling breeders to decide between direct and indirect selection . [5,6] Therefore, correlation and general relationships studies between yield-determining traits give an indication of the responses due to selection based on individual traits . [7]