Author(s):

Dr. S Nithila, K Venkatasalam, D Santhoshkumar and V Kavipriyan

Abstract: The production and productivity of several crops continues to be adversely affected due to various biotic and abiotic stress. With rise in atmospheric temperature, the biotic and abiotic stresses are predicted to become more severe and adversely affect the stability and productivity in pulse crops. The abrupt climatic change, particularly the erratic rainfall is one of the major causes for reduction of pulse production in India. Drought is the major constraints faced in rain fed areas so screening of genotypes for drought tolerance is the need of the day, by using physiological traits as a parameter. Drought during the late vegetative period (Trifoliate leaf formation) is tolerance in legume plants. Salinity in agricultural field is thus a severe constraint to crop growth and productivity in many regions and the situation as become a global concerns. <em>In vitro</em> drought and salt screening methods facilitates progress in our understanding of drought and salt resistance in pulse crop. The higher molecular weight substance poly ethylene glycol (PEG) causes osmotic shock which is one of the component to induce drought. Three green gram varieties were used for screening study. The green gram varieties VBN 2, ADT3, CO 8 were screened for tolerance to four levels of drought stress created by using poly ethylene glycol (PEG6000). Drought stress was applied in four concentrations of PEG 6000 that provide solutions with water potential equal to -0.1 MPa, -0.2 MPa, -0.3 MPa, -0.6 MPa. For imposing salt stress NaHCO₃solution of 25mM and 50mM were prepared and compared with control. The statistical design adopted is FCRD. <em>In vitro</em> condition the following parameters Viz., Germination percentage, Shoot and root length, vigour index and stress tolerance index was measured. Based on the drought and salt tolerance screening results revealed that with increasing concentrations of PEG and salts lead to decrease in seedling growth. Seed germination and seedling growth are major factors deciding the establishment of crops under stress conditions. Among these varieties VBN 2 recorded higher stress tolerance index followed by ADT 3 and CO 8. To conclude the tolerant greengram genotype could effectively utilized in hybridization programme to develope drought and salt tolerant greengram genotype

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