Anther culture in connection with induced mutations for rice improvement

Doubled haploids have long been recognized as a valuable tool in plant bree ding since it not only offers the quickest method of advancing heterozygous breeding lines to homozygosity, but also increases the selection efficienc y over conventional procedures due to better discrimination between genotyp es within any one generation. Ten cultivars of japonica rice and nine culti vars of indica rice were evaluated for androgenic response. Various doses ( 10-50 Gy) of gamma rays were applied to investigate the effect of radiation on callus formation, green plant regeneration and the frequency of selecte d doubled haploid mutants. Similarly, the effects of colchicine concentrati on (10-200 mg/l) on callus induction, regeneration and fertility of green p lants were observed. It was demonstrated that the dose of 20 Gy gamma rays and 30 mg/l concentration of colchicine have significant stimulation effect on regeneration of green plants from rice anther culture. The high frequen cy of observed doubled haploid mutants indicates that anther culture applie d in connection with gamma rays is an effective way to improve rice cultiva rs.