AGRO-MORPHOLOGICAL AND PHYSIOLOGICAL RESPONSES OF BRASSICA RAPA ECOTYPES TO SALT STRESS

Salt stress is one of the major abiotic stresses that affect normal morpho-physiological and biochemical processes of Brassica rapa. In present study the effect of salt stress on three important ecotypes of B. rapa (brown sarson, yellow sarson and Toria) was studied. The plants were regenerated at four NaCI levels (0, 50,100 and 150 mmol). The effect of salt stress on shoot length, root length, shoot fresh and dry weight, root fresh and dry weight, leaf relative water content (RWC), proline and chlorophyll a, b, a+b contents were recorded. The high salt stress significantly decreased the shoot length, root length, shoot fresh weight, shoot dry weight, and root fresh weight and root dry weight of all three ecotypes. The genotype 25007 (brown sarson) showed better morphological performance followed by Toria as compared to other genotypes. The RWC values and chlorophyll a, b and a+b contents were decreased up to several fold at high salt levels (50,100 and 150 mmol), while proline contents increased at these concentrations. Maximum RWC values and proline contents were recorded in genotype 25007 followed by Toria. The chlorophyll a, b and a+b amounts were higher in Toria followed by 25007 respectively. The brown sarson and Toria ecotypes showed better performance at high salinity levels as compared to yellow sarson. The resulted screened salt tolerant genotypes will be useful for salt affected area.