Promising rice mutants with high yields, good grain quality, and disease resistance due to irradiation technology

Three rice genotypes of NPT4, NPT5, and QP-5 were successfully selected through mutation breeding using Co60 gamma rays with 250-300 Gy. Of the three lines, two genotypes, NPT4 and NPT5, obtained high yields of 8.9-9.2 tonnes/ha, had growth duration of 103-110 days in the season of autumn and 130-135 days in the spring season. They exhibited dark green leaves, which were found to be adapted to intensification. They were resistant to major pests and diseases, and tolerant to major abiotic stress due to unfavourable conditions, as compared to the popular rice hybrids of Nhi Uu 868, Thien Nguyen Uu 9, and HYT100. The grain quality properties of NPT4 and NPT5 genotypes were also found to be good, identified as such due to their light aroma and amylose content of 15-16%. The genotype QP-5 exhibited a high grain quality and high yield of 6.5-7.0 tonnes/ha, with a growth duration of 105-110 days, and 125-135 days in autumn and spring seasons, respectively. The aromatic rice genotypes offered 10-12% amylose content and became more delicious as compared to the Bac Thom 7 variety.