Effect of glycine betaine in the alleviation of abiotic stresses in groundnut genotypes

Abstract

Many of the biotic and abiotic stresses faced by grain legumes contributr to the large yield gap between potential and realzed yields. Abiotic stresses occurring at critical growth stages in groundnut affect productivity by reducing the total dry matter, pod yield and quality. Present study investigates thc role of glycine bctninc in nllevintiny cll'ccts of the three major abiotic stresses i, e., drought, heat and salinity on selected groundnut genotypes. The investigation was conducted in 3 phases (a) effect of betaine on tolerance of groundnut seedlings to heat and salinity stress conditions, (b) effect of betaine on isolated plants growing in pots subjected to drought, heat and salinity, and ( c) effect of betaine on tolerance of groundnut genotypes to simulated drought under field conditions. The experiments were conducted during 1996- 98 period at ICRISAT centre, Patancheru in laboratory, glass house, growth chamber and field. (a) The seedlings were subjected to high temperature and salinity stress conditions in laboratory with and without glycine betaine trcatmcnt, under high temperature stress conditions, the seedlings with betaine treatment are able to produce root and shoot lengths (34 and 40%) than seedlings without betaine treatment, in the non induced treatments, there was a 122% greater growth in betaine treated seedlings compared to untreated ones, correspondingly the gel electrophoresis results indicated that betaine treatment was able to produce four new proteins with molecular weights of 76.4, 60.6, 54.6 and 16.5 kDa. Similarly under salinity stress conditions, the betaine treatment was able to produce 30 and 32% more root and shoot growths. The protein profiles indicated that betaine treatment was able to produce four new proteins with molecular weights of 65.4, 37.8, 35.4 and 16.5 kDa. These stress shock proteins which are produced under high temperature and...