Studies on genetic diversity and inheritance of fertility restoration in pigeonpea [Cajanus cajan (L) Millsp.]

A set of 68 pigeonpea germplasm lines was evaluated for the assessment of genetic diversity. Investigation elucidated wide range of genetic divergence among germplasm lines for seven yield related characters. Mahalanobis D² analysis grouped 68 genotypes into nine clusters. Cluster I was the largest consisting of 18 genotypes, followed by cluster VI with 11, and cluster II and cluster III with 9 genotypes each. Cluster VIII was the smallest with only one genotype. The inter cluster D² values revealed that most diverse clusters were cluster I and IX (276.8), whereas the minimum inter cluster D² value was observed between cluster III and IV (48.8). The highest intra cluster distance was observed in cluster VII (39.4) followed by cluster XI (32.7) and I (31.2) indicating high variability within the cluster. Cluster VIII showed highest mean values for plant height (293.5), secondary branches/plant (28.0) and test weight (8.3), while cluster IX revealed highest mean values for number of pods/plant (341.2) and seed yield/plant (71.7). While cluster II showed lowest mean for most of the characters viz., secondary branches/plant (14.2), number of pods (72.8), number of seeds/pod (2.9) and seed yield/plant (14.9). So the promising genotypes with good yield attributing traits viz., plant height, number of pods/plant, number of seeds/pod and 100-seed weight can be selected and could be further used in crossing programs for the selection of desirable transgressive segregants. On the basis of plant fertility and pollen viability, a cross combination (AL 100A × AL 1599) was taken for studying genetics of fertility restoration. On the basis of genetic ratios of F₂, BC₁F₁ and F₃ populations it was observed that fertility restoration was controlled by two duplicate dominant genes.