GENOME-WIDE ASSOCIATION STUDIES IDENTIFYING ADAPTIVE TRAITS IN CLIMATE-STRESSED CROP VARIETIES

Abstract

Background: Climate change is expected to be a significant threat to agricultural productivity across the globe by creating more droughts, heat stress, and salinity stress, which will lead to reduced crop growth and yield stability. It is therefore crucial that adaptive genetic traits associated with climate resilience are identified to be used for creating stress tolerant varieties that continue to support food security amidst changes in the environment.

Objective: The current study was undertaken to resolve the use of genome wide association studies (GWAS) to uncover the genetic architecture of adaptation to climate stress for crop varieties.

Methods: A collection of different populations of crop germplasm were phenotyped under controlled drought and heat stress conditions. To identify significant marker-trait associations related to stress adaptation mechanisms, SNP genotyping was performed at high throughput, the population was structured and genome-wide association mapping was performed.

Findings: A number of important adaptive gene-loci associated with drought tolerance, resistance to heat and antioxidant regulation were identified. The Three-way interaction of the two Genus species and 13 biotic factors accounted for 19–28% of the phenotypic variance for adaptive traits explained by the major SNP markers. The stress-tolerant varieties maintained almost a third more chlorophyll than the sensitive varieties, with a relative water content that was 30% higher and increased biomass stability. The relationships among the physiological and yield-related traits were higher in the case of climate stress conditions.

Conclusion: GWAS helps generate genomic information that can identify adaptive traits, and it can be used to optimize marker assisted breeding to create crop varieties more tolerant to stress and with improved yield in times of climate change.