Genetic Study of the Rice Embryo Culture In Vitro

The embryo culture in vitro response was examined among ten rice (Oryza sativa L.) cultivars and 26 cross combinations to evaluate the correlation between callus induction rate and differentiation rate with plantlet regeneration rate, the influence of parents to hybrid Fl embryo culture in vitro as well as the cytoplasmic effects. Plantlet regeneration rate was used as the product of callus production and regeneration capacity. The ten pure-lines, the five F1s and their reciprocal hybrid as well as the ten F1s among the ten lines were evaluated for callus production and regeneration capaticy. Significant variation was observed among the 36 genotypes in callus induction rate, callus differentiation rate and plantlet regeneration rate on embryo culture in vitro. The positive correlation between general callus induction rate and differentiation rate with plantlet regeneration rate was significant. There was a similar trend for callus induction rate between maternal parents and Fis during mature embryo culture in vitro. However, parent-offspring correlation for callus differentiation rate and plantlet regeneration rate were nonsignificant. Whether cytoplasmic effects for embryo culture response exist among the six pure-lines was examined py the differences between reciprocal F1 hybrids. The extent of cytoplasmic effects depended on cross combination.