Application of mutation breeding techniques in the development of green crop varieties in Sri Lanka: the way forward.

Abstract

Abstract The Department of Agriculture (DOA) in Sri Lanka initiated mutation breeding in the 1960s with the introduction of a cobalt-60 source. The first rice mutant variety, MI 273, was released for general cultivation in 1971. M1 273, derived from irradiation of the H-4 variety, was identified as a drought-tolerant variety. An indirect rice mutant variety, developed by crossing the short mutant line BW267-3 with a highly adaptable variety, was released as BW 372 in 2013. It is moderately tolerant to blast, bacterial leaf blight, brown plant hopper, gall midge and iron toxicity, and thus increases productivity to 3-4 t/ha on lands prone to iron toxicity. The most popular groundnut variety cultivated in the country, 'Tissa', is a mutant developed by irradiation with gamma-rays at 200 Gy. It showed attributes of high yield, medium maturity (90-100 days) and high oil content (42%). 'Tissa' presently covers 80% of the groundnut cultivated area in Sri Lanka. A sesame mutant line, derived from the variety MI-3 irradiated at 200 Gy with 60Co gamma-rays, was released as 'Malee' (ANK-S2) in 1993. It is a high-yielding variety (1.1-1.8 t/ha) resistant to Phytophthora blight. A cherry-type mutant tomato variety, developed by irradiation of seeds with gamma-rays (320 Gy), was released as 'Lanka Cherry' in 2010. Improved attributes are pear-shaped fruits and bacterial wilt resistance. Narrow genetic variability in many crops is a constraint to the development of new varieties adapted to the changing climate. Hence, the DOA is emphasizing integration of induced mutagenesis in conventional breeding programmes to develop resistant/tolerant varieties having high yield, quality and health-promoting functional properties in field and horticultural crops. The newly installed gamma irradiation chamber facilitates the creation of genetic variability in food crops, thus paving the way for the development of greener varieties.