Diversity pattern elucidating choice of parents for hybridization in varieties of groundnut, Arachis hypogaea L.

Abstract

Genetic divergence within and between the four varietal groups, Spanish bunch, Valencia, Virginia bunch and Virginia runner, of groundnut (Arachis hypogaea L.) was assessed by Mahalanobis's D² statistic using a representative sample of 40 germplasm lines in each group. Estimates of divergence were based on 17 characters spanning the seedling, flowering, post-flowering and harvest stages. The diversity within bunch groups was high enough to form six different clusters out of the total sixteen. The method used was thus efficient in diagnosing within-group divergence. The clustering pattern of the varieties remained essentially the same when the experiment was repeated on a sub-sample of 48 germplasm lines in the next season. The results revealed that identified bunch x bunch crosses involving divergent parents could combine earliness with productivity, and should be used to complement the currently advocated bunch x runner crosses. Flowering time, weight of mature pods, shelling percentage and seedling attributes, like number of leaves and shoot-root dry weight ratio, were found to be important in assessing genetic variance.