Capturing agro-morphological variability for tolerance to terminal heat and combined heat–drought stress in landraces and elite cultivar collection of wheat

Abstract

Climate change has resulted in extreme temperature and drought around the globe, which poses serious threat to food security. Both heat and drought stress affects the production and productivity of wheat crop. The present study was undertaken to evaluate 34 landraces and elite cultivars of Triticum spp. for phenological and yield-related traits under optimum, heat, and combined heat–drought stress environments during 2020–2021 and 2021–2022. The pooled analysis of variance showed significant genotype × environment interaction, suggesting an influence of stress on trait expression. The trait performance of genotypes exhibited significant reduction under combined heat–drought stress as compared to optimum and heat stress environments. The maximum seed yield penalty was observed under combined heat–drought stress environment as compared to heat stress alone. Regression analysis indicated significant contribution of number of grains per spike towards stress tolerance. Based on Stress Tolerance Index (STI), genotypes Local-17, PDW 274, HI-8802, and HI-8713 were identified to be tolerant to both heat and combined heat and drought stress at Banda, whereas genotypes DBW 187, HI-8777, Raj 4120, and PDW 274 were tolerant at Jhansi location. The genotype PDW 274 showed stress tolerance under all treatments at both the locations. The genotypes PDW 233 and PDW 291 showed highest stress susceptibility index (SSI) across the environments. The number of grains per spike and test kernel weight were positively associated with seed yield across the environments and locations. The selected genotypes Local-17, HI 8802, and PDW 274 were identified to be the potential sources of heat and combined heat–drought tolerance, which may be utilized in hybridization to develop tolerant wheat genotypes and also for mapping of underlying genes/quantitative trait loci (QTLs).

Investigating the impact of terminal heat stress on contrasting wheat cultivars: a comprehensive analysis of phenological, physiological, and biochemical traits

“…When stress occurs during grain filling, it leads to diminished starch and protein accumulation ( Bhullar and Jenner, 1985 ; Zahedi et al., 2003 ), hastened plant development, premature leaf senescence, and reduced photosynthetic rate and capacity ( Stone and Nicolas, 1995 ; Tewolde et al., 2006 ). Ultimately, these effects culminate in smaller grain size ( Wardlaw and Wrigley, 1994 ; Stone and Nicolas, 1995 ; Sharma et al., 2008 ; Talukder et al., 2014 ) and lower grain yield ( Tewolde et al., 2006 ; Talukder et al., 2014 ; Kumar et al., 2021 ; Kumar et al., 2023a ). Plants employ various major adaptive mechanisms to develop thermotolerance.…”

Heat stress tolerance indices for identification of the heat tolerant wheat genotypes

“…Low TOL as well as grain yield should be taken in consideration for selection of high yielding genotypes. Dorostkar et al 35 and Kumar et al 2 revealed similar results in wheat genotypes under both conditions. According to Erdemci 36 and Shabani et al 37 STI is a more appropriate parameter to screen tolerant genotypes of chickpeas.…”

“…The selections based on MP typically boost the average performance of genotypes in both stress and non-stress conditions and fail to make a distinction between stress-tolerant and high-yielding genotypes. MP favours higher yield potential and lower stress tolerance 2 . In our studies based on HM, MRP, GMP and STI genotypes HD 2967 had the highest values.…”

“…As a result of climate change, there are more extreme temperatures because of less rainfall, changing rainfall pattern, and distribution, as well as shorter winter seasons. The most detrimental abiotic stresses for the growth and development of crop plants, impacting yield potential and the final quality of food items, are drought and heat stress 2 . High temperature stress that limits productivity of important crops including wheat, is likely to increase due to continued change in global climatic conditions 3 .…”

“…Additionally, heat stress affects a number of metabolic processes, including protein synthesis, the inactivation of enzymes, and cellular physiological processes, including cell membrane degradation. Heat stress also negatively impacts cell division 2 . In wheat during the anthesis to grain maturity stage, 22–25 °C is optimum temperature beyond this it causes irreversible damage 8 .…”