Gahukar, Dr. S. J.TANDALE, RAM MHATARDEO2018-07-262018-07-262017-01-18TANDALE, RAM MHATARDEO. (2016). MOLECULAR AND BIOCHEMICAL CHARACTERIZATION FOR WATER STRESS TOLERANCE IN WHEAT GENOTYPES. Department of Agricultural Biotechnology, Dr.Panjabrao Deshmukh krishi vidyapeeth, Akola. M. Sc. 2016, xiii, 104p. (Unpublished).http://krishikosh.egranth.ac.in/handle/1/5810062072Drought is a major constraint to food production because it limits plant growth and development, ultimately reducing crop yield. Crop plants have adopted different strategies to tolerate drought stress and these include reduction in water loss by increasing stomatal resistance, increased water uptake, accumulation of osmolytes, waxes and late embryogenesis abundant (LEA) proteins especially low molecular weight dehydrin. One of the possible ways to bring drought area under cultivation is by growing drought tolerant cultivars. Present study was carried out to evaluate wheat cultivars on morphological, physiological, biochemical and molecular basis for drought tolerance.Drought affects crop growth and yield by altering metabolic and physiological processes. Plants tolerate drought through osmotic adjustment, stomatal resistance, increased water uptake and accumulation of waxy layer. Cultivars possessing drought tolerant traits may be promising candidates for drought prone regions. The present study was planned for molecular and biochemical characterization for water stress tolerance in wheat genotypes. In this study various morphological, physiological, biochemical and molecular observations were recorded. Drought stress was created with different concentrations of PEG-6000 (-2, -4, -6, and -8 bars) and by withholding of water at moderate and sever level. On the morphological basis, all cultivars exhibited decline in germination percentage, speed of germination, shoot-root length, coleoptile length, seedling fresh and dry weight under water stress environments. While on biochemical basis proline has direct relationship with osmotic stress and water stress while total chlorophyll content has inverse association with osmotic stress and water stress. On the physiological basis, with increase in water stress photosynthesis rate, relative water content decrease while epicuticular wax content increased with an increase in osmotic stress and water stress conditions. All these parameters finally extremely affect the yield of wheat genotype. At the end for drought response, wheat cultivars were evaluated on molecular basis. A set of trait specific 18 SSR primers were used for identification of drought tolerant genotypes. From which 16 primers gave polymorphic result and amplified unique band as result of drought tolerance. AKW-381 followed by AKAW-4627, AKAW-4210-6, AKAW-4498 and AKAW-4842 performed best at various stress levels for germination percentage, speed of germination, root-shoot fresh and dry weight, total chlorophyll content, proline, Rate of photosynthesis, wax content, and relative water content. The performance of HD-2189, GW-322, NIAW-917 and AKAW-3722 was poor. On molecular basis expected size unique band was amplified in the tolerant genotypes AKW-381, AKAW-4627, AKAW-4210-6, AKAW-4498 and AKAW-4842. It can be concluded that water stress levels had substantial effect on germination and seedling growth. Morphological, biochemical, physiological and molecular analysis revealed that adequate genetic difference for drought tolerance existed in the tested genotypes. AKW-381 and AKAW-4627 may prove a promising parent material for breeding drought tolerant wheat cultivars. Further molecular investigations are suggested to assess the genetic basis of drought tolerance. AKAW-4627, AKAW-4210-6, AKAW-4498 and AKW-381 may be considered better genotypes for low rainfall or drought prone areas.ennullThesis