Rice germplasm enhancement by induced mutations in Chile

Summary

The main goals of the rice breeding program in Chile are: cold tolerance, earliness, long and translucent grain and disease resistance. It has been very difficult to combine in one genotype the long and translucent grain with earliness. Therefore, six varieties or the selected Chilean lines: ‘Diamante-IMA’, ‘Cilia 606’, ‘BuliINIA’, ‘Cinia 609’, ‘Quella-INIA’ and‘Quila 31808’ were irradiated with 200 Gy of gamma rays at the Chilean Atomic Energy Agency. The main objective was to induce greater variability in order to select for earliness and to breed for resistance against sheath and stem rot. The results have shown that some mutant lines of varieties Diamante-INIA, Buli-INIA and lines Cinia 606 and Cinia 609 are at least 6 days earlier than the parent varieties or lines. During 1997/98 under field conditions, plants were inoculated with Rhizoctonia oryzae salivae. Great variability was found in Cinia 609, in relation to the length of lesion after the inoculation and seven M₃ families had lesions less than 1 cm in length.