COMPARISON AMONG TWELVE EXOTIC ACCESSIONS OF TOMATO (SOLANUM LYCOPERSICUM L.) FOR ROOT AND SHOOT DEVELOPMENT UNDER POLYETHYLENE GLYCOL INDUCED WATER STRESS

Abstract

Genetic variation for tolerance in the gene pool of the species for which increased tolerance is a primary requisite in selecting and breeding for drought tolerance. Inter-specific and intra-specific variation for drought tolerance provides scope for selecting for its improvement. Hence, this study was carried out to evaluate and compare the drought tolerance in 12 exotic tomato accessions viz., ‘Ailsa Craig’ (LA2838A), ‘Floradade’ (LA3242), ‘Condine Red’ (LA0533), ‘New Yorker’ (LA2009), ‘Pennheart’ (LA0020), ‘Hotset’ (LA3320), ‘Edkawi’ (LA2711), M-82 (LA3475), ‘VC-82’ (LA1706), ‘Solanum pennellii’ (LA0716), ‘Solanum chilense’ (LA0722) and ‘Solanum pimpinellifolium’ (LA0458). These accessions of tomato were evaluated and ranked for drought tolerance at seed germination and seedling stage under water stress induced by polyethylene glycol (molecular weight of 8000) in full strength Hoagland nutrient solution at T1= only nutrient solution; T2 = 2.5%; T3 = 5.0% and T4 = 7.5% (w/w) concentrations and to evaluate its effect on seed germination and rate, seedling growth, biomass and relative water content. Two-week-old accessions were subjected to various levels of PEG₈₀₀₀-imposed water stress for a period of two weeks. Significant decrease was recorded for all the attributes with increasing concentration of PEG₈₀₀₀ but maximum decrease was recorded at T3 treatment. Overall, wild genotypes performed well under various levels of stress whilst ‘Ailsa Criage’, ‘M-82’ and ‘UC-82’ were noted as sensitive genotypes. Remaining genotypes performed intermediate under water stress conditions. In view of these studies it seems plausible that through selection and breeding we can improve the drought tolerance of crop species.