Tissue culture of Pakistani rice varieties: I- Optimization of physical factors

ABSTRACT

A study for optimizing appropriate explant, conditions for sterilization and physical environments was conducted using rice varieties Bas -370, IR-6 and KS-282. Sterilization of seeds was better obtained in HgC12 than chlorox [Commercial sodium hypochlorite] but due to lesser seed germination after HgC12 treatment, chlorox was prefered over the other. Chlorox treatment increased the subsequent callus induction in seeds. However, nodal portions and root tips were damaged by the treatments. Out of mature seeds, nodal explants and root tips, seeds proved to be the best explant for callus cultures, 28°C was the best temperature for callus induction and callus multiplication in the seeds. However for organogenesis 26°C was the optimum. Light, complete dark or 16 h day length played no significant effect in callus induction. Callus formation frequency was maximum at a pH ranging from 5.5 to 7.0. Beyond this pH range there was a sharp decline in callus induction, multiplication and plant regeneration