Some chemical treatments on Kluai Khai through tissue culture for mutation breeding

Polyploidy of in vitro Kluai Khai plantlets were induced by different concentrations of the two mutagens : 0, 0.5, 0.75 and 1 percent colchicines and 0, 15, 30, 45 mM oryzalin containing 2 percent DMSO for 2.5, 5.0, 7.5 hours. It was found that the higher the mutagen doses and the longer the treatment duration. The less the survival rates. After treating plantlets with colchicines and oryzalin at 0.4, 0.5, 0.75 percent and 13, 15, 22 micro M, respectively the survival rate of each one was found to be 50 percent. In MV1, adventitious bud initiation of mutagenic treatment yielded 0.2-1.2 shoots which was lower than those in the control while those of MV2 and MV3 were not significantly different from each other. Treated plantlets were revealed to be abnormal in chimera and stomata sizes were larger than those of the controls. The plantlets with stomata over 28 micro m were selected for chromosome count. The controls were diploid (2n=22) whereas three selected clones were tetraploid (2n=44) derived from 1 percent colchicines at 7.5 hours and 45 micro M oryzalin at 2.5 hours. The mutants were then subcultured. The number of suckers of mutants was less than those of the control. MS medium without plant growth regulator was observed to give the best rooting of all treatments. After transferred to the greenhouse, the height of the controls and the colchicines treated plants were revealed to be significantly different from the oryzalin treated ones which were shorter with low survival rate. The results obtained in the field were similar to those in the greenhouse. The foliage of all mutants appeared more drooping with larger stomata cell, lower in stomata number per area and thicker than those of the controls. The numbers of leaf and sucker of each mutant were not significantly different from the controls.