Selection of Salt Tolerant Variants by Radiation and in vitro Culture in Rice

Abstract

To select salt tolerant variants of rice, NaCl tolerant cell lines were selected from the embryo-cultured callus irradiated with gamma ray. The callus mass (g) and survival rate of irradiated (30, 50 Gy) calli were more increased than those of non-irradiated calli on the 1.5% NaCl-supplemented medium. Regenerants (M1) were obtained from the tolerant callus which was cultured for 30 days on the auxin-free medium. M1 plants were grown at the NaCl-free field and harvested M2 seeds at the time of 150 days after transplanting. M3 generation 5,000 lines were obtained from M2 lines which establish an ear-to-row pedigree nursery. The 350 M3 lines were selected on the solution with 1% NaCl as being cultured from germination stage to 2~3 leaf stage. Twelve tolerant lines among 350 M3 lines were selected at the saline field near the sea coast (10~14 mS). Of the 12 lines, the agronomic traits of two lines (M3-128-12 and M3-130-4) were more significantly increased than those of original variety such as spikelets numbers, tillering and grain yield. Combination of radiation techniques with in vitro culture methods can be applied to select salt tolerance.