A new index for evaluation of G×E interaction in pearl millet using AMMI and GGE biplot analyses

Performance of a genotype is the result of its genetic constitution and the environment in which it has been grown. In practice, a particular variety may not exhibit the same phenotypic performance under different environments. Also, different varieties may respond differently to a specific environment. Additive Main effects and Multiplicative Interaction (AMMI) and GGE biplot analyses are the most frequently used models to explain G×E interaction of multi-environment cultivar trials. Based on climatic conditions, the pearl millet cultivation in India is divided in 3 major zones A1, A and B for effective evaluation of the pearl millet breeding material. In the present study, the G×E interaction in pearl millet genotypes from zone-A of India has been evaluated using the techniques of AMMI and GGE biplot analyses. A new Weighted Stability Index (WSI) has been proposed for determining the high yielding and stable genotypes based on the normalized indices for grain yield and ASV indices. The three interaction principal component axes (IPCA1, IPCA2 and IPCA3) have been found to be significant for this zone. AMMI Stability Value (ASV) and Stability Index have been used to find the most stable genotypes while indices YSI and WSI have been used to find both the most stable and high yielding genotypes. On the basis of ASV, genotypes MH 2120, MH 2109 and MH 2116 have been found to be the most stable for this Zone. The Spearman’s rank correlation coefficient between YSI and WSI was found to be significant at 1% level of significance indicating that the two indices have almost similar performance in determining high yielding stable genotypes.