Morpho-physiological variability and stability of early maturing thermo tolerant Indian mustard (Brassica juncea L. Czern&Coss) genotypes for seed yield under heat stress condition in semi-arid region of India

Abstract

 Impact of climate change like global warming, drought, flooding, and other extreme events are posing severe challenges
 to global crop production. Heat stress at seedling stage is one of the major factors responsible for the low productivity
 of crop plants and has become an increasing threat for agriculture. Indian mustard grown under rain-fed conditions is
 usually affected by heat stress at seedling stages resulting in negative effect on yield. In this context, the selection of
 heat tolerant genotypes may be one of the remedies. Therefore, a study was carried out at the research farm of ICAR
Indian Institute of Rapeseed-Mustard Research, Bharatpur, Rajasthan during Rabi 2018-19, 2019-20 and 2020-21 to
 estimate stability and morpho-physiological variability of early maturing thermo-tolerant genotypes in order to identify
 some of the promising early maturing heat stress tolerant advanced breeding lines. The crop was raised strictly under
 conserved moisture early sown conditions. G x E interaction was significant for all the characters viz., days to flowering,
 days to maturity, seed yield (kg/ha), membrane stability index (%), excised leaf- water loss (%), relative water content
 (RWC %), and water retention capacity of leaves (%) except 1000-seed weight. G x E interaction (linear) was also
 significant for all these eight characters, indicating substantial amount of predictable G x E interaction. All ten genotypes
 were tested for three stability parameters, namely mean, bi
 and S2di. Genotype DRMRHT-13-13-5-4 attained minimum
 days to maturity (122.88) alongwith regression coefficient near to unity and S2di near to zero considered as stable. While
 the genotype DRMRHT-13-13-5-5 attained minimum days to maturity (124.44) alongwith regression coefficient near to
 unity exhibit average stability.