Pollen fertility Vs Spikelet fertility in F2 of a CMS based hybrids in rice (Oryza sativa L.) under Aerobic condition

Identification of maintainer and restorers from rice germplasm through test crossing is the initial step in three line heterosis breeding. Maintainer lines can be converted into cytoplasmic male sterile lines to utilize in development of rice hybrids. Restorer lines can be used as males to produce F1 hybrids. Three hundred F2 plants of the cross KCMS 26A X IET 19886 were grown under aerobic situation and fifty randomly selected plants were analyzed for per cent pollen fertility (using one per cent I-KI solution) and per cent spikelet fertility. Based on the per cent pollen fertility (PF %) the individual plants were grouped as effective restorer (>96% PF), partial restorer (21-95% PF), partial maintainer (6-20% PF) and maintainer (<5%PF) lines. Based on spikelet fertility (SF %) individual plants were grouped as effective restorer (>80% SF), partial restorer (21-79% SF), partial maintainer (1-20% SF) and maintainer (<1%SF). There was strong evidence for relationship between pollen fertility and spikelet fertility. Potential restorer is one, that would produce high per cent of seed set in F1 while, a potential maintainer would produce 100 per cent sterile pollen in F1. The results in the current study with F2 progenies of a cross involving male sterile line indicated that spikelet fertility and pollen fertility are the potential traits in identification of restorer and maintainer lines, respectively.