Variation in Anther Culture Response and Fertility of Backcrossed Hybrids between Indica and Japonica Rice (Oryza sativa)

This study was conducted to investigate the variations of fertility, callus induction and plant regeneration in backcrossed hybrids between a responsive japonica variety (Mankeumbyeo, recurrent parent) and a recalcitrant indica variety (Ranta Emas, donor parent) to anther culture. The mean spikelet fertility of inter-subspecific F1 and BC1F1 hybrids was 33.5% and 67.2%, and the spikelet fertility of BC1F1 among backcrossed hybrids showed the most extensive variation (a low of 4.5% to a high of 90.6%). The mean fertility and distribution range in BC5F1 hybrids were almost the same as that of the japonica recurrent parent (94.6%). The mean callus induction of F1 and BC1F1 hybrids was higher than that of donor parent, and the distribution range in BC1F1 hybrids varied from a low 0% to a high 18.7%. The mean callus induction and plant regeneration of BC4F1 hybrids was almost that of japonica recurrent parent, and there were no statistical differences between BC4F1 and BC5F1 hybrids. These results may help to accelerate the introgression of desirable traits from indica into japonica rice using anther culture of backcross hybrids as a breeding strategy.