Distribution and Inheritance of the Fertility Restorer Genes for WA-CMS in Wild Rice with AA Genome

It is very important to research the fertility restorer genes ( Rf ) for cytoplasmic male sterility (CMS) in wild rice for our better understanding the origin of the Rf , the interaction between cytoplasm and nuclear, and the development of new restorer lines. For such an end, the distribution and inheritance of the Rf for Wild-abortive (WA) CMS in wild rice with AA genome were investigated. The results showed that: (1) Sixteen out of the 31 test-crossed wild rice accessions were identified having Rf genes, and the frequency of the Rf in wild rice accessions was 51.6%. (2) The wild rice accessions with Rf fell into four species of genus Oryza , and majority of them belonged to the species of O. nivara and O. rufipogon . (3) The fertility of the microspores in the spikelets of the hybrid F 1 between Yuetai A and wild rice accessions ranged from 10%-90%, of which, six wild restorer accessions' F 1 were over 80%, six accessions 50%-80%, and the other four accessions lower than 50%. Majority of the accessions with complete restoring ability belong to the annual specie of O.nivara . (4) The distribution of the wild rice accessions with Rf were imbalance in geography, 14 accessions from Asia and two wild rice accessions from Africa carried restorer genes, the wild rice accessions from Oceania and Latin America all contained no Rf for WA-CMS. (5) Apart from one out of the randomly selected eight accessions having two pairs of restorer genes, the other seven accessions all possessed only one pair of restorer allele. Further allelic analysis showed that among of the six randomly selected accessions, the Rf alleles in w15, w29 and w34 were all un-allelic to that of Milyang 23, and whereas the Rf between w15 and w34 was also un-allelic. Therefore, we speculate that there are at least three restorer alleles in the six tested wild restorer lines.