<div>Background: The microspores of five tropical japonica and five indica rice genotypes were subjected to androgenic studies. The effect of growth regulators on callus induction were studied to improve the anther culture efficiency.&nbsp; 
 
Methods: The cold pre-treatment of panicles at 10&deg;C were done at different days of intervals viz., 5, 8, 10 and 12 days. The microspores at uninucleate stage were selected and dusted after pre-treatment. The anthers were cultured in N6 basal media supplemented with casein hydrolysate (250 mg/L), proline (250 mg/L), silver nitrate (100 mg/L), maltose (50 g/L) and growth regulators.&nbsp; 
 
Result: The 8 days of cold pre-treatment initiated calli in most of the ten genotypes. The days taken for callus induction varied with genotype from 32-55 days. The callus induction frequency ranged from 1.41 to 5.12%. The responsive genotypes (Azucena, Palawan, Nira) on callus induction were studied for their regeneration potential.&nbsp;Background: The microspores of five tropical japonica and five indica rice genotypes were subjected to androgenic studies. The effect of growth regulators on callus induction were studied to improve the anther culture efficiency.&nbsp; 
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Optimization of Pre-treatment Incubation Period on Callus Induction Response in Anthers of Selected Rice Genotypes