Genetic diversity of Tanzanian and Kenyan adapted landraces of cowpea, sorghum and pigeonpea

DISSERTATION TO BE SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENT FOR THE DEGREE AWARD OF MASTER OF SCIENCE IN CROP SCIENCE OF SOKOINE UNIVERSITY OF AGRICULTURE. MOROGORO, TANZANIA. 2016

Improvement of cowpea, pigeonpea and sorghum can be enhanced by knowledge of genetic diversity available between and within accessions. This variability is the foundation of all three crop improvement programs. A total of 85 accessions as 22 cowpea, 32 pigeonpea and 31 sorghum from Tanzania and Kenya gene banks were used for this study. Quantitative and qualitative traits such as, grain color, grain coverage, seed shape, days to 50% flowering, plant height, days to 50% maturity and grain yield were among the few traits used to assess the collected accessions. The main objective of the study was to determine existing diversity of three food security crop accessions in Tanzania. Different agro- morphological traits collected were analyzed using GENSTAT 15 and XLSTAT 2014 statistical packages to determine Phylogenetic relationship of the three selected crops based on agro-morphological traits. Accessions were classified based on their agro-morphological relationships using principal component analysis and un-weighted pair-group average cluster analysis. Results showed a relatively high level of genetic diversity between and within both accessions; levels of similarity differed for qualitative and quantitative data for all three crops. Some quantitative agro-morphological traits such as days to 50% flowering, days to maturity, seed width, pods per plant in cowpea, grain weight per panicle, grain number per panicle, grain yield, number of nodal tillers per plot in sorghum; days to maturity, plant height and raceme number per plant in pigeonpea. For qualitative traits, raceme position for cowpea; grain color and bird attack for sorghum; seed color pattern for pigeonpea were distinguished more efficiently between and within the accessions to get superior materials for future use in breeding programs. A few of the best materials selected were GBK 013187 (cowpea), TZA 2496 (pigeonpea) and TZA 3991 (sorghum). In a number of groups the accessions were different from other accessions in some important traits. Implications of the variability in pigeonpea, cowpea and sorghum improvement are discussed.