Studies on stability of cytoplasmic male sterile lines and their floral traits influencing outcrossing in rice (Oryza sativa L)

One of the problems encountered in the hybrid breeding of crop plants is the pollen shedding in male sterile lines under certain environments; hence, studies on cytoplasmic male sterility (CMS) breakdown and relative stability of CMS lines for their sterility was undertaken. Twelve CMS lines were evaluated over two seasons at Delhi. The CMS lines PMS2A. PMS3A and PMS 10A were completely pollen sterile, had zero spikelet fertility and hence highly stable while PMS SA and IR 58025A were stable. Remaining CMS lines were unstable. The CMS lines PMS 3A, PMS 10A and IR 58025A had comparatively longer stigma, style and anthers length favourable for outcrossing during seed production of Ax B and A x R combinations. In general, all CMS lines were semi-dwarf in height had medium to high tillering and medium duration except IR 62829A (early). The differential response of CMS lines possessing one kind of cytosterile source ‘wild abortive (WA)′ observed was due primarily to differences in nuclear background of CMS lines and interactions of cytoplasm with nuclear genes.