Concepts of breeding derived from experiments in peanut( Arachis hypogaea L.)

Abstract

The initial step of a breeding programme is as vital as the final improved yield desired by a breeder. An analysis of experimental evidence in the light of underlying genetic concepts suggests a choice of parents on genetic divergence given by a multivariate measure. Breeding programmes initiated from heterotic F₁'s envisage a greater probability of success in further generations compared to programmes initiated from any F₁ including non-heterotic ones. Limits to parental divergence are therefore set to realize F₁ heterosis. Large F₂ populations of heterotic F₁'s need an ordering process to locate productive recombinants. A method of forming a ranked F₂ distribution is suggested using values of a selection index based on physiological and yield components. Selection intensity of the order of 25% is most often adequate to derive desirable selection in F₃ and superior lines in F₅.