Development of callus colonies the isolated microspore culture of Capsicum annuum L

Androgenesis in Capsicum annuum L. via isolated microspore culture, with a limited scope, was studied. Donor genotype, i.e. U-130, was a doubled haploid. Intact flower buds containing microspores from early to late uninucleate stages were pretreated with a mannitol starvation medium both at 10 and 35 degree C for 7 days. High temperature treatment tested here, although considered effective in Capsicum anther culture, was detrimental and therefore flower buds from this treatment were not used. Following pretreatment at 10 degree C microspores were isolated and cultured on NLN medium (20) without growth regulators. Osmoticum and carbon was supplied to the microspores with 100, 130, and 170 g/1 sucrose. Only 170 g/1 culture was maintained and the rest of the cultures were lost to contamination. Callus colonies were obtained on the 30th and 60th days at rate of 40.5 and 67%, respectively. Callus colonies were subcultured to MS media containing 2, 4-D at 1 and 2 mg/1, but further development was not obtained. It was concluded that the approach adopted earlier on the cellular and molecular characterization studies of induced multinucleate Capsicum microspores (12, 14, 15) may lead to high frequency regeneration of haploids via callus colonies, as obtained in the present study, hence, isolated microspore culture using mannitol starvation as pretreatment has potentiality in Capsicum annum L. breeding.