[Re-analysis of wide compatibility in rice]

Utilization of heterosis between rice subspecies has fascinated rice breeders for several decades. One of the main obstacles is the hybrid sterility in the F1 populations of subspecies crosses in rice. Wide compatibility varieties are considered to an important way to overcome the problem. But the genetics of the wide compatibility is controversial. This paper dealt with the problem through three kinds of triple crosses in which a wide compatibility variety, Ketan Nangka, was involved. Pollen fertility, spikelet fertility and the correlationship between the two fertilities were analyzed in the three kinds of triple crosses. The results suggested that male and female sterilities existed in indica-japonica hybrids at the same time, while the contribution of male sterility to spikelet fertility varied from cross to cross; The characteristic of wide compatibility in different triple crosses was coordinated with the hybrid sterility between the indica and japonica test varieties used; Ketan Nangka possessed the wide compatibility genes on the loci in which the male and female sterilities between the test varieties were involved; The genetics of wide compatibility gene S-5 fitted to one locus sporo-gametophytic interaction model.