Title : Genetic gain, gene action, genetic diversity and G×E in crop improvement
Abstract:
Genetic diversity of sixty four exotic inbred lines of maize were studied for yield and yield components, maturity and growth parameters at BARI, Gazipur, Bangladesh. Principal component analysis revealed that the first principal axis largely accounted for the variation among the genotypes which alone contributed 44.13% of the variations followed by the 2nd axis (30.75%) while the first six eigen values for the principal component axis of genotype accounted for 97.55% of the total variation among 10 characters. The sixty four inbreds were grouped into six clusters using the non-hierarchical clustering method where the maximum (18) and minimum(4) number of inbreds were comprised into cluster III and V, respectively. The highest inter cluster distance of 9.37 was observed between cluster VI and III followed by 8.22 between cluster VI and V, 7.75 between cluster V and I suggesting wide diversity between them and the genotypes in these cluster could be used as parents for new hybrid development. Twenty one single cross hybrids developed through a half diallel fashion using seven selected parents were subjected to genotype-environment interaction and stability analysis at three locations of Bangladesh adopting AMMI Model. Two commercial hybrid varieties (BHM 7 and NK 40) were used as check. Based on phenotypic index, 13 hybrids showed high yield while the rest performed low. Among the hybrids, WL4×WL5 (10.49 t/ha), WL1×WL3 (9.78 t/ha), WL2×WL3 (9.49 t/ha), WL1×WL4 (9.53 t/ha) and check NK 40 (10.51 t/ha) exhibited the higher grain yield, bi~1 and S2di~0 indicated that the hybrids are stable across the three environments. According to environmental index, Gazipur and Barisal were poor whereas Rangpur exhibited the best environment for hybrid maize production.
