Studies on multiple pistillate (polycaryoptic) male sterile rice

The multiple pistillate rices selected from the combination HR 1619-6-2-1-2-2/ Double Rice were crossed to the cytoplasmic male sterile rice HR 1619 A having the WA cytoplasm. The F₁ plants which showed male sterility were crossed again with the parental multiple pistillate lines. The multiple pistillate cytoplasmic male sterile (MPCMS) lines having semi-dwarfness could be selected from the backcross progenies. The number of panicles per hill and the number of florets per panicle of the MPCMS lines were not of difference from those of the cytoplasmic male sterile (CMS) lines with normal pistils. The multiple pistillate genetic male sterile (MPGMS) lines could be selected from the F₄ of the cross IR 36 ms/Double Rice. The less number of panicles per hill and the less number of florets per panicle were observed in the MPGMS lines than in the genetic male sterile (GMS) lines with normal pistils. The average seed set percent of the multiple pistillate male sterile lines in cytoplasmic or in genetic male sterile rices was statistically not higher than that of the male sterile lines having normal pistils. The lager variation of outcross rate was observed in the multiple pistillate male sterile rices than in the normal pistillate male sterile ones. The outcrossed seed set percent of the MPCMS and MPGMS lines ranged from 1.1% to 34.8% and from 0.4% to 40.5%, while that of the CMS and GMS lines from 1.2% to 21.3% and from 1.5% to 36.7% respectively.