Assessing genetic variation for heat stress tolerance in Indian bread wheat genotypes using morpho-physiological traits and molecular markers

Abstract

Heat stress greatly limits the productivity of wheat in many regions. Knowledge on the degree of genetic diversity of wheat varieties along with their selective traits will facilitate the development of high yielding, stress-tolerant wheat cultivar. The objective of this study were to determine genetic variation in morpho-physiological traits associated with heat tolerance in 30 diverse wheat genotypes and to examine genetic diversity and relationship among the genotypes varying heat tolerance using molecular markers. Phenotypic data of 15 traits were evaluated for heat tolerance under non-stress and stress conditions for two consecutive years. A positive and significant correlation among cell membrane stability, canopy temperature depression, biomass, susceptibility index and grain yield was shown. Genetic diversity assessed by 41 polymorphic simple sequence repeat (SSR) markers was compared with diversity evaluated for 15 phenotypic traits averaged over stress and non-stress field conditions. The mean polymorphic information content for SSR value was 0.38 with range of 0.12–0.75. Based on morpho-physiological traits and genotypic data, three groups were obtained based on their tolerance (HHT, MHT and LHT) levels. Analysis of molecular variance explained 91.7% of the total variation could be due to variance within the heat tolerance genotypes. Genetic diversity among HHT was higher than LHT genotypes and HHT genotypes were distributed among all cluster implied that genetic basis of heat tolerance in these genotypes was different thereby enabling the wheat breeders to combine these diverse sources of genetic variation to improve heat tolerance in wheat breeding programme.

Genotypic Variation and Genotype × Environment Interaction for Yield‐Related Traits in Synthetic Hexaploid Wheats under a Range of Optimal and Heat‐Stressed Environments

“…Few studies have reported on the performance of SHWs and their derivatives under heat stress, and most reports are limited to determination of superiority over their respective recurrent wheat parents (Sehgal et al, 2011; Sharma et al, 2014; Cossani and Reynolds, 2015). In this study, the performance of 137 SHWs was evaluated under timely and late sowing to identify genetic variation for important agronomic traits under heat stress.…”

“…tauschii , providing a valuable resource for widening the genepool of bread wheat (Ogbonnaya et al, 2013). Sharma et al (2014) screened 24 SHWs under timely and late sowing and concluded that SHWs are an extremely useful source of heat tolerance. However, relatively few of the available SHWs have been characterized for heat tolerance.…”

Heat stress in crop plants: its nature, impacts and integrated breeding strategies to improve heat tolerance

“…Additionally, higher value of chlorophyll fluorescence parameter F v /F m was observed in wheat, which reflected maximum efficiency of PSII higher photosynthesis rate , higher stomatal conductance and transpiration rate under HS (Sharma et al. ). Further, the above parameter was also used in assessment of genetic variability for HS tolerance in wheat (Sharma et al.…”

“…Further, the above parameter was also used in assessment of genetic variability for HS tolerance in wheat (Sharma et al. , ). Other strategies such as measuring canopy temperature were also implemented for identifying high‐yielding HS‐tolerant wheat lines with lower canopy temperature (Pinto et al.…”

“…In the same way, three synthetic wheat lines, viz. SYN 11, SYN36 and SYN44, were declared as highly tolerant to heat based on cluster analysis of morphological attributes and ISSR markers (Sharma et al 2014a).…”