Study on heat stress indices and their correlation with yield in Indian mustard genotypes under diverse conditions

Increasing temperatures are becoming a major challenge for agro-systems. Late mustard planting often results in overall growth reduction, poor metabolism, less productivity and yield due to heat stress at the terminal stage. A set of 45 genotypes comprising introgression lines, landraces, wild species, induced mutants, advance breeding lines and the released varieties/cultivars were evaluated under normal (Yp) and stressed environment (Ys) for yield stability during 2016-2018. The higher value of heat tolerance index, geometric mean productivity, yield stability index, relative stability index and yield production score index with lower heat susceptibility index indicated tolerance to high temperature in some genotypes. Based on the yield performance and derived traits, six genotypes namely, HLM-41-13-2 and ELM-38 with zero erucic acid quality, MCN-05-8 an induced mutant, germplasm lines PCR-3 and CSR-1163, while MCN-08-2 is released variety RB50 were rated as promising for heat stress tolerance at both the locations. Biplot analysis indicated that genotypes under group I and IV are tolerant of high yield potential and stability in a stressed environment irrespective of location.