Genotyping of a mapping population derived from salt susceptible and salt tolerant varieties (IR 28 x Pokkali) of rice

Rice is the most important staple food crop in India having wide adaptability across diverse agro-ecosystems. A set of recombinant population was developed by hybridizing IR 28 with Pokkali to tag salt tolerant gene(s). Pokkali is a tall, traditional, photosensitive, profuse tillering, lodging susceptible, extremely long duration, low yielding cultivar. It is generally grown in the coastal area of Kerala owing to high degree of tolerance towards salinity. It is being used as international check for salinity tolerance screening trials. This cultivar possesses long, broad, dark and droopy leaves. In contrast, IR 28 is a high yielding, dwarf, medium grained, short duration variety, having extreme sensitivity to salinity. This indica/indica hydridization was designed to combine high yielding ability of IR 28 with high salinity tolerance of Pokkali. Phenotyping of F sub(3)s and parents were done under NaCl (12 dSm super(-1)) stressed condition. Genotyping, using random primers, showed ample polymorphism, which revealed that F sub(3) segregants had high genetic variation and could be very useful as mapping population to tag salt tolerant loci. Further, the study has also revealed that RAPD is an efficient tool to display polymorphism and to tag the targeted gene(s).