Abstract Development of aluminium toxicity tolerant rice through in vitro screening at cellular level

Bikash Chowdhury, A.B.Mandal* and A.K.Bandyopadhyay

Biotechnology Laboratory, Central Agricultural Research Institute, Post Box No.181, Port Blair 744101, India.

(Received 15 December 1997 / Accepted 19 February 1998)

Abstract.
Two indica rice varieties, a HYV viz. IR-18351-229 3 and a traditional cultivar C14-8, indigenous to Andamans were employed as experimental materials to recover aluminium (AI) tolerant genotype/s through in vitro screening with simulated excess Al stress in culture medium. Mature dehusked seeds were callused on MS medium with 250mg^-1 casein hydrolysate and 2mg^-12,4-D. Aluminium at 30, 60 and 90 ppm in the form of AICI₃. 6H₂O was supplemented in the callus induction medium (CIM) as a stressing agent. Seed germination, callus induction, callus health and morphogenetic responses in both varieties were found to be influenced by this abiotic stress. Induced calli were passaged three times over normal and two times on Al stressed callus maintenance medium (CMM). At the end of each selection, calli from 20 seeds in each treatment were separated into embryogenic and non embryogenic components under stereomicroscope to document percentage of embryogenic calli and note their health status. Putative Al tolerant genotypes were recovered from survivor calli of both varieties on Al free regeneration medium. However, only a few regenerants from C14 8 could qualify screening test under hydroponics with 30ppm Al stress. This clearly indicates differential tolerance norm at cellular and whole plant level in response to Al toxicity tolerance. These tolerant plants could flower and mature normally thus offering ample scope to developing Al tolerant lines. These lines may be used directly or through conventional recombination breeding.

Keywords: Aluminium Toxicity, Rice, in vitro Screening