Induction and selection of hydroxy-L-proline resistant mutant in rice (Oryza sativa L.).

Abstract

The growth inhibiting effect of hydroxy-L-proline (Hyp) on rice seedlings and the selection technique for a resistant mutant in M2 seedlings were studied. Retardation of seedling growth was detected in the culture at concentrations above 5×l0-5 M Hyp and increased with the increase in both Hyp concentration and the soaking time prior to addition of Hyp. In M2 generation, the seedlings following gamma-ray irradiation and treatment with sodium azide, ethylene imine (EI) and ethyl methanesulfonate were cultured in the presence of 2×10-4 M Hyp. Twenty-seven resistant seedlings were selected. EI was the most effective mutagen for inducing Hyp resistant variants in rice. Following 0.2% and 0.4% EI treatments for 2hr, the frequencies of resistant seedlings were 2.5×l0-4 and 1.6×l0-3 on an M2 seedling basis, or about a tenth of that of chlorophyll mutations in both cases. Of the progenies of selected seedlings, 24 progenies were confirmed to be resistant to Hyp at M3 and established as rcsistant mutant strains.