Abstract
Drought is one of the important constraints affecting rice productivity worldwide. The vigorous shoot and deep root system help to improve drought resistance. In present era, genome-wide association study (GWAS) is the preferred method for mapping of QTLs for complex traits such as root and drought tolerance traits. In the present study, 114 rice genotypes were evaluated for various root and shoot traits under water stress conditions. All genotypes showed a significant amount of variation for various root and shoot traits. Correlation analysis revealed that high dry shoot weight and fresh shoot weight is associated with root length, root volume, fresh root weight and dry root weight. A total of 11 significant marker-trait associations were detected for various root, shoot and drought tolerance traits with the coefficient of determination (R2) ranging from 18.99 to 53.41%. Marker RM252 and RM212 showed association with three root traits which suggests their scope for improvement of root system. In the present study, a novel QTL was detected for root length associated with RM127, explaining 19.30% of variation. The marker alleles with increasing phenotypic effects for root and drought-tolerant traits can be exploited for improvement of root and drought tolerance traits using marker-assisted selection.
Highlights
Drought is the major abiotic stress that deleteriously affects rice productivity in the rainfed ecosystem (Kumar et al 2020)
The marker alleles with increasing phenotypic effects for root and drought-tolerant traits can be exploited for improvement of root and drought tolerance traits using marker-assisted selection
The present study showed lack of correlation between root traits and drought tolerance might be due to differences in genotypes present in the study, screening technique and environment in which experiments were conducted
Summary
Drought is the major abiotic stress that deleteriously affects rice productivity in the rainfed ecosystem (Kumar et al 2020). Drought stress significantly reduces rice yield from 2550% (Zhang et al 2018; Daryanto et al 2017) and causes an economic loss of $37 billion (Kim et al 2019). There is a need to improve the productivity of rice cultivated in drought-prone areas. This has necessitated the development of drought-tolerant varieties to combat the moisture stress problem. Genome-wide association study (GWAS) is the preferred method for mapping of QTLs for complex traits such as root and drought tolerance traits. 114 rice genotypes were evaluated for various root and shoot traits under water stress conditions. All the genotypes were genotyped using 65 SSR markers covering all 12 chromosomes for the identification of various QTLs for root and shoot traits using MLM (Q+K) model in GWAS
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