Influence of genotype and culture medium on microspore callus induction and green plant regeneration in anthers of Oryza sativa

Attempts to identify nutritional requirements of anthers of eight indica rice cultvars (Oryza sativa L. spp. Indica) for callus induction in vitro and green plant regeneration were made. The requirements varied with the genotype. Some cultivars, however, possessed a wide range of adaptability to diverse nutritional conditions. Indica rice is highly sensitive to the presence of NH+4, and MgSO4 in the medium. High sucrose concentration (11%) was deleterious for callus induction and green plant regeneration. Sucrose at 3 to 5% was optimal for growth. Auxins at high concentrations promoted regeneration of albino plants. The presence of 2,4‐dichlorophenoxyacetic acid (9.0 μM) supplemented with picloram (0,3 μM) and zcatin (0.5 μM) was effective for callus induction. A combined pretreatment of 35°C for 5 min followed by 10°C for 7 days was most suitable for callus induction and green plant regeneration.