Characterization of ‘GolSam’ Lines Developed from the Cross between Samgwang and 5MT Resistant Lines in Rice

Rice grain quality is usually observed by its chalkiness and is affected by genetic effects of endosperm, cytoplasm and maternal plant. Controlling the chalkiness in rice can be a very challenging task because it is affected by genotype and environmental factors. The present study aimed to introduce 5-methyl tryptophan (5MT) resistance from the 5MT resistant mutants into Samgwang, a high grain and eating quality Korean variety by introgression of, resulting to elevated tryptophan content in grains. The progenies generated from single crosses of two different cross combinations were phenotyped based on agronomic traits and by 5MT growth inhibition test. Through direct PCR sequencing, the inheritance of single base mutation (F124V) in OsASA was selected among the progenies. The latter generations were used to analyze the grain and eating quality of the selected lines. Inbred lines (S4-10, S4-28, and S5-11) carrying the point mutation in OsASA and with reduced chalkiness plus good eating qualities were successfully generated. Tryptophan content in the milled grains of the selected lines showed 2 - 4 times higher (mg/100 mg) than the maternal parent. The three selected lines, S4-10, S4-28, and S5-11, were later renamed as GolSam-1, GolSam-2, and GolSam-3 respectively.