Enhancement of Panicle Blast Resistance in Korean Rice Cultivar ‘Saeilmi’ by Marker Assisted Backcross Breeding

Panicle blast is a serious disease in rice production in Korea. To develop rice cultivar resistant to panicle blast, the Pb1 gene, originating in the indica cultivar ‘Modan’, was incorporated into an elite japonica cultivar ‘Ilmi’, which is highly susceptible to panicle blast, by marker assisted backcross breeding. ‘Hwayeong’ was selected as the donor parent for the Pb1 gene based on 10 years of panicle blast data. The inheritance of panicle blast resistance in ‘Hwayeong’ is controlled by a single dominant gene. This panicle blast resistance gene, Pb1, from ‘Hwayeong’ was incorporated into the susceptible variety, ‘Ilmi’, by marker assisted backcross approach using DNA marker RM206. As a result, ‘Saeilmi’ containing the Pb1 gene showed resistance to panicle blast. The agronomical and grain quality traits of ‘Saeilmi’ were similar to those of the recurrent parent ‘Ilmi’. Molecular background analysis revealed that ‘Saeilmi’ had the least donor segment introgression in the locus of the Pb1 gene on chromosome 11.