ROLE OF OSMOLYTES IN DEGREE OF WATER STRESS TOLERANCE IN TOMATO

Abstract

Eleven local/exotic tomato genotypes were examined thoroughly to estimate the accumulation of various osmolytes like proline, soluble sugars and free amino acids at different water regimes i.e., at 80% of field capacity (optimum watered), 60% and 40% of field capacity (drought) conditions. Significant decrease was recorded for leaf relative water content, water potential and osmotic potential therefore, leaf osmotic adjustment significantly increased due to increase in osmolytes. Although wild type tomatoes are water stress tolerant, they are not preferred for market view point whereas stress tolerant tomato genotypes (Lyallpur-1 and CLN1767) were found better adopted by maintaining relatively higher plant water status and osmotic adjustment with respect to sensitive genotypes. In view of these results, it could thus be concluded that sufficient genetic variation exists in tomato genotypes and water stress tolerance which is associated with degree of osmotic adjustment and can be used as selection marker in breeding for stress tolerance.