Association of leaf chlorophyll content with the stay-green trait and grain yield in wheat grown under heat stress conditions

Abstract

Heat stress is a major production constraint of wheat in South Asia, particularly in the Gangetic plains of India and Bangladesh. The leaf chlorophyll status is a key determinant for a high rate of photosynthesis under stress. The present experiments included 238 genotypes in 2016–2017 and 321 genotypes in 2017–2018 under optimum and under heat stress conditions. Subsequently, a set of 100 genotypes selected on basis of the heat susceptibility index was evaluated in 2018–2019 under heat stress conditions to study the relationship between important physiological traits and yield under stress. A significant correlation of soil plant analysis development (SPAD) value of the two upper leaves with stay-green trait and grain yield indicates the importance of chlorophyll content, both in flag and penultimate leaf, in maintaining leaf areas under greenness (LAUG) and grain yield under heat stress. The SPAD in the flag and penultimate leaf was responsible for 8.8% and 10.9%, respectively, of the variation in grain yield. For the stay-green trait, 8.4% and 7.2 % of the variation was governed by the SPAD value in the flag and penultimate leaf, respectively. These results suggest that, in addition to the flag leaf, the chlorophyll status of the penultimate leaf can be an important criterion for the selection of superior wheat genotypes under heat stress. The genotypes SW-139; SW 108; DWR-F8-35-9-1; NHP-F8-130; DWR-F8-3-1 that maintained a high chlorophyll content in the flag and penultimate leaf can be used further in breeding programmes addressing heat resistance in wheat.

Relationships between Some Spectral Traits and Grain Yield in Bread Wheat under Rainfed Conditions

“…These results show that NDVI can use to estimate the grain yield. Similar results were reported by Roy et al (2021), Marti et al (2007), Sultana et al (2014), Morgounov et al (2014), Mekliche et al (2015).…”

“…The highest SPAD values was obtained from centre of Konya followed by İçeri Çumra and Gözlü locations respectively with 48.28, 47.36 and 44.13 (Table 3). As reported by some researchers like Roy et al (2021), there were differences in SPAD values among genotypes. The highest SPAD (51.64) was recorded on Genotype 3 (Karahan 99) (Table 4).…”

Characterisation and evaluation of wheat genetic resources for heat stress tolerance using stay-green traits

“…The SG trait is an important character that enables the plant to better adapt under high temperatures by providing assimilates to the developing grain for a longer period as compared to the non-SG trait. Genotypes showing SG traits are associated with a delayed leaf senescence rate and increased yield (Christopher et al 2008;Chen et al 2018;Sui et al 2019;Roy et al 2021). Plant growth regulator (PGR) brings physiological adaptations in response to heat stress, including the interactive effects and cross-talk of various PGRs on plant physiological and biochemical mechanisms (Sabagh et al 2021).…”

“…During the reproductive stage, colder canopies were linked to higher aerial biomass, more grains, and higher yields in wheat (Rebetzke et al 2012;Lepekhov 2022). Many reports have suggested that low CT under heat stress can advance yields (Amani et al 1996;Balota et al 2007;Rutkoski et al 2016).…”

Genomic approaches for improving grain zinc and iron content in wheat

“…In rice, grain Zn concentrations depend on plants’ ability to redistribute Zn from older leaves and stems, as well as phloem mobilization of Zn ( Wu et al, 2010 ). Significant contributions of the flag and penultimate leaves to wheat grain yield have been observed ( Roy et al, 2021a ), but there are no detailed studies concerning the proportionate remobilization of Zn and Fe from different wheat plant parts. Uauy et al (2006) observed an abundance of Zn, Fe and proteins in wheat flag leaves during grain filling, in plants carrying the Gpc-B1 locus.…”