Discriminant function method of selection in Vegetable Cowpea [Vigna unguiculata (L.) Walp.]

Sixty diverse genotypes of vegetable cowpea were evaluated for twelve characters in order to construct selection indices. The characters, which had desirable correlation as well as moderate to high direct effect on green pod yield per plant were considered as selection index criterion. The green pod yield per plant (X₁) along with its three components viz., number of pods per plant (X₂), pod length (X₃) and ten pod weight (X₄) were utilized for the construction of selection indices. The discriminant function had higher genetic gain and relative efficiency over straight selection for green pod yield per plant alone. The relative efficiencies of selection indices constructed in combinations of two or more characters were ranged from 3.99 to 136.46%, while genetic advance ranged from 3.99 to 136.28g. There was an increase in genetic gain and relative efficiency with inclusion of an additional trait in the character combination. A selection index involving green pod yield per plant, number of pods per plant, pod length and ten pod weight (X₁.X₂.X₃.X₄) followed by green pod yield per plant, number of pods per plant and ten pod weight (X₁.X₂.X₄) or green pod yield per plant, pod length and ten pod weight (X₁.X₃.X₄) could be advantageously exploited in the vegetable cowpea breeding programmes.