Effect of physical desiccation on plant regeneration efficiency in rice (Oryza sativa L.) variety super basmati.

This experiment assessed the effect of partial physical desiccation on plant regeneration efficiency in scutellum-derived embryogenic calluses of rice (Oryza sativa L.) variety Super basmati. A number of callusing cultures were developed, and efficient callus induction was observed on MS (Murashige and Skoog) basal medium supplemented with 2.0mg/L 2,4-dichlorophenoxy acetic acid. The calluses were proliferated on the same medium for 3 weeks and then shifted to dehydration desiccation treatment for 72h. The desiccated calluses were cultured on different media for somatic embryogenesis and plant regeneration. A medium with 2.0mg/L alpha-napthaleneacetic acid, 10.0mg/L abscisic acid , 2.0mg/L kinetin was best for somatic embryogenesis only, but not for further plant development. After 10d, differentiated calluses were sub-cultured on medium with various concentrations and types of carbohydrates (carbon source) in (1)MS(2j) medium. A large number of plantlets (14.51+/-2.81 and 8.56+/-2.90 plants/callus) were regenerated via chemical desiccation, on MS with 3% maltose+3% sorbitol and 6% sucrose, respectively. Under dehydration on only simple MS (3% sucrose), 11.23+/-3.22 plants/callus were developed. Under conditions of dehydration and chemical desiccation, plant regeneration rates were higher than the calluses cultured on simple MS medium in the presence of plant growth regulator. After somatic embryogenesis, >25% plants were sterile. The protocol used here may allow maximum regeneration of normal and fertile plantlets of super basmati rice within 3 months.