The effect of plant growth regulators on anther culture response and plant regeneration in selected Sri Lankan Indica rice varieties, Japonica varieties and their inter-sub specific hybrids.

The effect of 2, 4-Dichlorophenoxy acetic acid (2, 4-D), ∝-Naphthalene acetic acid (NAA) and Kinetin in anther culture of Japonica rice variety Hu lo tao, Indica rice varieties BG 90-2, BG 379-2 and their F1 hybrids for high frequency of callus induction and plant regeneration was investigated. Anthers were cultured in N6 medium containing 5% sucrose and variable amounts of 2,4-D, NAA and Kinetin. The cultures were placed in the dark at 28+ 2 C for callus induction. When the calli reached 1-2 mm in diameter they were transferred to half strength Murashige and Skoog (MS) medium supplemented with 2.0 mg l Kinetin and 0.5 mg l NAA. The effect of variety and the growth regulator combination for the callus induction frequency was significant at 5% significance level. Indica cultivars had the lowest callus induction (ranging from 0.0% 5.0%) while Japonica and Indica × japonica F1 hybrids had comparatively high (ranging from 5.0% 35.3%) callus induction. The F1 hybrid Hu lo tao × BG 90-2 had a significantly high level of callus induction than the other genotypes ranging from 13.6% 35.3%. Both F1 hybrids had a high callus induction frequency than the Japonica and Indica parents. The addition of 2,4-D 2.0 mg l and Kinetin 0.5 mg l had the highest callus induction frequency for all the parental varieties and F1 hybrids.Plant regeneration (green, albino) was significantly high in Japonica parent and F1 hybrids. Highest plant regeneration was observed in Kinetin 0.5 mg l + 2,4D 2.0 mg l (T12) treatment in all the genotypes.