IDENTIFICATION OF WHEAT MUTANTS WITH IMPROVED DROUGHT TOLERANCE AND GRAIN YIELD POTENTIAL USING BIPLOT ANALYSIS

Water shortage resulting from climate change has become one of the major threats to agricultural production globally. Performance of 68 mutants (M 4 ) of wheat (Triticum aestivum L.), 35 of Bhittai and 33 of Kiran-95 varieties, induced by gamma-rays were evaluated, along with wild-types and a drought-resistant check, under three irrigation treatments, viz., T-1(no irrigation), T-2 (two irrigations) and T-3 (four irrigations). Drought susceptibility index (DSI) and relative yield (RY) values were used to describe yield stability and yield potential of wheat genotypes. BM-14, BM-15, KM-26, and KM-27 had the lowest DSI (.3, .18, -0.1,0.27) and higher relative yield under stress (.88, 1.00,1.00,1.00), than all other entries and check varieties; indicated better performance under water-deficit stress. A significant positive association was observed between biomass and grain yield in both the mutant populations of Bhittai (r=0.61) and Kiran-95(r=0.83) under T-1. However, a significantly negative relationship was observed in DSI with grain yield (r=-0.70; r=-0.68), biological yield (r=-0.30; r=0.67), and harvest index (r=-0.66; r=-0.29) in Bhittai and Kiran mutants, respectively. Principal component analysis (PCA) identified seven of Bhittai and llof Kiran-95 mutants for both water-stress and irrigated conditions. Furthermore, mutants with low DSI and high RY could be employed to breed varieties with both high yield stability and high yield potential (DSI<1 and RY>mean RY) for drought-prone areas.