KASP genotyping reveals disease resistance and yield enhancement in swarna introgression lines

Abstract

Deployment of marker-assisted selection (MAS) in the molecular breeding programmes has transformed the crop breeding over the last decade, bringing speed and precision to the breeding programmes. The experiment was conducted during rainy (kharif) seasons of 2019, 2020, and 2021 at ICAR-Indian Institute of Rice Research, Rajendranagar, Hyderabad, Telangana for validation of the Kompetitive Allele Specific PCR (KASP) SNP markers for routine marker- assisted selection through genotyping and phenotyping of a set of breeding lines segregating for grain number, yield and resistance to bacterial blight and blast diseases. Initially, 150 introgression lines of Swarna possessing bacterial leaf blight (Xa21), blast (Pi54) and yield enhancing gene (Gn1a) at ICF4 generation were genotyped using trait specific KASP markers, and a set of 22 plants was identified to be homozygous for all the three genes, 68 plants were found positive for two genes possessing either Xa21 + Gn1a and Pi54 + Gn1a, rest were having different single gene. Simultaneously, plants which were triple gene positives were also subjected for stringent phenotypic screening for the targeted stresses, viz. bacterial blight and blast disease resistance and further evaluated for grain number and other key agronomic traits. All the three-gene positive plants exhibited high level of resistance to bacterial blight and blast diseases in comparison with positive checks and displayed higher grain number and yield than the recurrent parent, Swarna. The efficiency of SNP marker system provided by Intertek is accurate, cost effective and accurate with phenotype.

Keywords

• Bacterial blight, Blast, Grain number, KASP, Rice, SNP