Abstract

High temperature is a major environmental stress that devastatingly affects wheat production. Thenceforth, developing heat-tolerant and high-yielding wheat genotypes has become more critical to sustaining wheat production particularly under abrupt climate change and fast-growing global population. The present study aimed to evaluate parental genotypes and their cross combinations under normal and heat stress conditions, exploring their diversity based on dehydration-responsive element-binding 2 gene (DREB, stress tolerance gene in response to abiotic stress) in parental genotypes, and determining gene action controlling yield traits through half-diallel analysis. Six diverse bread wheat genotypes (local and exotic) and their 15 F1 hybrids were evaluated at two different locations under timely and late sowing dates. Sowing date, location, genotype, and their interactions significantly impacted the studied traits; days to heading, chlorophyll content, plant height, grain yield, and its attributes. Cluster analysis classified the parents and their crosses into four groups varying from heat-tolerant to heat-sensitive based on heat tolerance indices. The parental genotypes P2 and P4 were identified as an excellent source of beneficial alleles for earliness and high yielding under heat stress. This was corroborated by DNA sequence analysis of DREB transcription factors. They were the highest homologies for dehydrin gene sequence with heat-tolerant wheat species. The hybrid combinations of P1 × P5, P1 × P6, P2 × P4, and P3 × P5 were detected to be good specific combiners for grain yield and its attributes under heat stress conditions. These designated genotypes could be used in wheat breeding for developing heat-tolerant and climate-resilient cultivars. The non-additive genetic variances were preponderant over additive genetic variances for grain yield and most traits under both sowing dates. The narrow-sense heritability ranged from low to moderate for most traits. Strong positive associations were detected between grain yield and each of chlorophyll content, plant height, number of grains/spike, and thousand-grain weights, which suggest their importance for indirect selection under heat stress, especially in early generations, due to the effortlessness of their measurement.

Highlights

  • Wheat (Triticum aestivum L.) is a widespread staple food crop [1]

  • The selected parents included two local genotypes obtained from Agricultural Research Center (ARC), Egypt, and four exotic genotypes obtained from the International Maize and Wheat Improvement Center (CIMMYT)

  • Genetic variations were detected among parents and their F1 hybrids for all measured traits under heat stress and optimal conditions

Read more

Summary

Introduction

Wheat (Triticum aestivum L.) is a widespread staple food crop [1]. Wheat is grown on about 216 million hectares and produced 766 million tons [1]. This large production is facing serious obstacles by the rising population, which is expected to reach more than 9 billion by 2090, and by climate changes [4]. High-temperature exposure after anthesis declines grain filling rate and duration, which reduces grain size and weight, reduces grain yield [15,16,17,18]. Developing heattolerant genotypes has become urgent to sustain wheat production under abrupt climate change and fast-growing global population

Methods
Findings
Discussion
Conclusion
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call