Standardization of optimum Polyethylene Glycol 6000 dose in groundnut (Arachis hypogaea L.) for in vitro screening against induced moisture stress

B. PREETHI; KAVERA BIRADAR; B. N. MOTAGI; RAMESH S. BHAT

B. PREETHI Department of Genetics and Plant Breeding, College of Agriculture, Hanumanamatti University of Agricultural Sciences, Dharwad - 580 005, India
KAVERA BIRADAR Department of Genetics and Plant Breeding, College of Agriculture, Hanumanamatti University of Agricultural Sciences, Dharwad - 580 005, India
B. N. MOTAGI Department of Genetics and Plant Breeding, College of Agriculture, Hanumanamatti University of Agricultural Sciences, Dharwad - 580 005, India
RAMESH S. BHAT Department of Genetics and Plant Breeding, College of Agriculture, Hanumanamatti University of Agricultural Sciences, Dharwad - 580 005, India

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Abstract

Groundnut (Arachis hypogaea L.) is an important oilseed crop in India and the second most important legume in the world, generally grown as a rainfed crop, where crop is frequently subjected to drought stress leading to 50-80 per cent yield loss. Therefore, identification of genotypes that have a better ability to use limited available water is critical to enhance crop productivity. Breeding for tolerance to drought is limited due to non-availability of rapid method of screening large number of genotypes. Hence, a fast-screening mechanism would be helpful in selecting valuable genotypes conferring drought tolerance. An attempt was made to standardize optimum Polyethylene glycol concentration to screen against induced osmotic stress under in vitro condition using 15 groundnut genotypes which included stabilized breeding lines and three released varieties as checks (Dh-256, TMV-2 and JL-24). The osmotic stress was induced using different levels of PEG 6000 (0, -3, -4, -5 and -6 bars) in the laboratory using two factorial complete randomized design with two replications during 2021-22. Significant differences were observed for germination per cent, lengths of root, shoot and seedlings, root and seedling length stress tolerance indices and seed vigour at different levels of PEG-6000 among the genotypes. There was also significant interaction between genotypes and PEG levels for all of the traits. The germination percentage and all the seedling traits exhibited greater reduction with the increase in the PEG concentration in comparison to control. The optimum concentration of PEG 6000 appeared to be -4 bar for screening groundnut genotypes for moisture stress tolerance under in vitro condition, since beyond -4 bars, germination and all the seedling traits have shown more than 50 per cent reduction compared to control (distilled water). Beyond -4 bars of PEG 6000 concentration seemed to have detrimental effect on seed germination and other seedling parameters.