Comparison of two indices for evaluating regeneration ability in rice (Oryza sativa L) through a diallel analysis

A full diallel analysis was performed among seven rice cultivars, all of which showed different abilities of regeneration from seed-derived calli. Number of regenerated shoots and regeneration frequency were used as indices of regeneration ability. In both cases, additive effects were significant at the 0.1% level, and dominant genes had a positive effect, that is, they increased regeneration ability. Non-allelic interaction (epistasis) and maternal effects were not detected. Dominance effects were significant at the 1% and the 0.1% level when the number of regenerated shoots and regeneration frequency were used as indices, respectively. Average degree of dominance was 0.531 for the shoot regeneration index and 0.990 for the regeneration frequency index. Since broad-sense heritability was 0.919 for number of regenerated shoots and 0.736 for regeneration frequency, the former was considered to be a better index of regeneration ability than the latter.