M. P. Wankhade, L. N. Jawale and D. S. Sutar Half diallel, cowpea, yield, combining ability 8-13 1 (2) 2017 November,2017 The present investigation was undertaken to study combining ability and nature of gene action for yield and yield contributing traits in cross involving eight parents of cowpea genotypes viz., Wali 4, Konkan Safed, C-152, VCM-8, DFC-1, GC-3, Pusa Falguni, Pusa-do-Phasli and their F’s (excluding reciprocal) obtained through diallel cross were evaluated during 2006 at Pulses Improvement project, M.P.K.V., Rahuri, Maharashtra. Six quantitative traits were studied during the investigation on five randomly selected plants from each genotype. The data were subjected to combining ability analysis as per method 2, model I of Griffing (1956) and Haymann (1954) diallel analysis for estimation of the genetic components, GCA and SCA. Analysis of variance revealed that significant level of diversity among the traits for both parents and their F1s. The GCA effects varied significantly for different characters and genotypes. The parent Wali-4, Pusa-do-Phasli, Konkan Safed and VCM-8 would be considered as good parents for isolating new strains through hybridization. The cross combination wali4 x DFC-1 was appeared to be the most promising for yield and its principal component.