The role of S1-g allele from Oryza glaberrima in improving interspecific hybrid sterility between O. sativa and O. glaberrima

Abstract

The HYBRID STERILITY 1 gene allele from Oryza glaberrima (S1-g) frequently causes sterility in F1 hybrids with O. sativa allele S1-a. We tested the hypothesis that O. sativa lines homozygous for the O. glaberrima sterile gene alleles would be more compatible with O. glaberrima than similar lines with O. sativa alleles. The S1-g allele was introgressed from O. glaberrima into three O. sativa backgrounds using marker aided selection. These S1-g lines and one check line (Dianjingyou 1) were used as males in interspecific hybridization with numerous cultivars of O. glaberrima and as the recurrent parents in backcrosses. Both the pollen grain fertility and egg fertility of progenies of S1-g lines were higher than those without S1-g in F1 and BC1F1 progenies. Spikelet fertility of BC2F1 progenies with S1-g gave similar results. The results indicated that O. sativa lines carrying S1-g allele from O. glaberrima can be used as bridge parents to significantly improve the fertility of hybrids between O. glaberrima and O. sativa.