GY*T biplot approach for genotypic selection in multiple trait evaluations: A case study of cowpea (Vigna unguiculata l.)

Abstract

In the present study, a novel genotype by yield*trait (GYT) biplot approach was validated to assess the comparative efficiency of GY*T approach over GT approach in genotypic selection on multiple traits in cowpea. Even though the Genotype by Trait (GT) biplot enables the comparison of genotypes on the basis of the measured multiple variables and also identifies genotypes that are particularly superior in certain traits it is not always efficient in selection or rejection of cultivars. Compared to the GT biplot approach where genotypes are ranked on the basis of their levels in individual traits, the GY*T biplot not only ranked genotypes based on their levels in combining yield with other target traits, but simultaneously showed their trait profiles in terms of their strengths and weaknesses. GY*T method is graphical, objective, effective, and straightforward and increases the goodness of fit as the variation accounted for by first two PC's is greater than GT approach.