Development of rice introgression lines with brown planthopper resistance and low amylose content for germplasm sources through marker-assisted selection

Abstract

The brown planthopper (BPH) is one of the most serious problems affecting rice production. This study incorporated the BPH resistance gene, Bph3, derived from a Rathu Heenati × Pathumthani 1 variety, which is susceptible to BHP and has low amylose content in the endosperm and both of these traits are closely linked on chromosome 6. The objective of this study was to develop introgression lines as germplasm sources with BPH resistance and low amylose content with other removed linkage drag traits and photoperiod insensitivity using marker-assisted selection. The newly developed multiplex simple sequence repeat markers specific to both genes were utilized for screening of the F₂ progeny possessing genotypes with breaking linkage drag and selected photoperiod insensitive lines. Then, evaluation of the selected lines for BPH resistance was conducted in the seedling stage of the F₄ progeny and the resistant character was segregated. Selection was made for BPH-resistant plants and their genotype controlling resistance on chromosome 4 was additionally determined using marker RM 16355. The results revealed that all the selected plants had the same genotype as the Rathu Heenati variety. Finally, the elite rice lines could be used as a germplasm source in rice breeding for BPH resistance and low amylose content. Moreover, unfavorable traits were removed by phenotypic selection from the Rathu Heenati variety such as photoperiod sensitivity, non-fragrance and tall plant type. Thus, these rice lines can be used as a germplasm resource for a rice breeding program in the future.