Genome-wide association study on root traits under non-stress and osmotic stress conditions to improve drought tolerance in rice (Oryza sativa Lin.)

Rice productivity is adversely affected by drought stress. Genetic improvement is key to enhance the rice productivity in the drought prone areas. Towards identification of genes/QTLs governing root system architecture, 162 rice genotypes were phenotyped for root traits viz. primary root length, total root length, area of root surface and average root diameter under non-stress and osmotic stress (− 0.15 MPa) in hydroponics conditions. 50 k SNP genotyping data of these genotypes were used for genome-wide association study (GWAS) to identify genes/QTLs for root traits. Thirty-six most significant QTLs for constitutive and stress inductive root traits were identified of which 10 were novel QTLs. In addition, several suggestive loci governing root traits were identified. The constitutive and stress inductive root traits can be utilized in development of rice varieties that can perform well under both irrigated and stress environments.