イネ

It is well known that auto-triploid plants yield aneuploid plants in their progenies, and they were useful sources for primary simple trisomic set. In rice plants, progeny seeds of triploid which were produced by self or cross pollination with diploid were developed poorly and almost all of them were impossible to germinate when they were sown in usual method as already reported. In these circumstances artificial culture method using White's culture medium was employed and several progeny plants of auto-triploid were produced. And also some knowledges with the chromosome number of progeny plants were obtained as follows. Imperfect seeds obtained by the cross pollination with diploid pollen grains germinated well on the artificial medium and some of them grew to adult plants, but they did not germinate when they were sown in usual method. As to the imperfect seeds obtained by self and cross pollinations with diploid as female parent, almost all of them did not germinate and only one progeny plant (0.4%) was obtained from the self pollination. Perfect seeds produced by each pollination were also sown on artificial medium. Over the 90% of them germinated and 50% grew to adult plants. Thus, 131 progeny plants of auto-triploid were produced from 904 seeds sown in total. In 49 progeny plants of which 34 were grown from perfect seeds and 15 from imperfect seeds, the chromosome number was determined by observation of pollen mother cells. In the other plants, chromosome number could not be determined because their pollen mother cells did not developed. Chromosome number of progeny plants distributed widely from 24 to 44-48 in total. The distribution was different according to the grade of seed development that was described as perfect and imperfect seeds in this paper. Among 34 observed plants which were grown from perfect seeds, 12 had 27 chromosomes, and the others distributed binomially from 24 to 30 chromosomes with 2 exceptional plants that had very high number of 44-48. On the other hand, the plants which were grown from imperfect seeds had relatively high chromosome number. Namely, of 15 plants observed, 8 had 33 and 34 chromosomes , and the others were distributed from 28 to 32 chromosomes. Thus, well developed seeds produced the plants that had relatively low chromosome number and poorly developed ones produced relatively high chromosome number.