Climate change is emerging phenomena and causing frequent drought which lead to scaricity of water, which ultimately nagetively affecting wheat (Triticumaestivum L.) yield all around the world. The aim of this study was to explore the potential deought tolerant wheat genotypes for candidate genes exploration. This study was conducted during the year 2014-2015 at Plant Physiology Division, Nuclear Institute of Agriculture (NIA) Tandojam. The six wheat genotypes (cv. MT-1/13, MT-2/13, MT-3/13, MT-4/13 Chakwal-86 and Khirman) were investigated for their response at germination and seedling stage under different water stress treatments (0, -0.5, -0.75 and -1.0 MPa) in controlled conditions. The results of experiments with reference to genotypes revealed that genotype Chakwal-86 shows maximum seed germination (82.58 %), while the genotype Khirman shows maximum shoot length  (7.23 cm), root length  (15.1 cm), shoot fresh wt. (5.85 g 10-1shoots), root fresh wt.  (3.45 g 10-1roots), shoot dry wt. (1.33 g 10-1shoots), root dry wt. (0.69 g 10-1roots). Among the genotypes tested Khirman and MT-4/13 are the tolerant genotypes had the potential to perform better under drought conditions, whereas  MT-4/13 and Chakwal-86 were moderate tolerant under water stress conditions. Moreover, the genotypes i.e. MT-1/13 and MT-2/13 are the sensitive genotypes under drought environment. It is concluded from present in-vitro studies that osmotic stress significantly reduced the seed germination shoot/root length fresh and dry weight in all six wheat genotypes. The maximum reduction was found at higher osmotic stress induced by PEG-6000 (-1.0 MPa) significantly.

Pakistan is one of the most severely affected countries by Global climate change, it is an agriculture based country and its economy (21%) mainly depend on agriculture production. Wheat is the major staple food crop in Pakistan and takes key position in the national economy. It contribute 12.5% share in agriculture and 2.9% in the country’s GDP. Frequent droughts and scarcity of the water severely affecting the wheat production. To fulfill the feed requirements of rapidly growing population, it is necessary to explore the advanced genetic resource that can be able to perform better in changing climate. Six wheat genotypes were tested for their early seedling and physiological performance under different water stress environments. The seeds of six wheat genotypes (Khirman, Chakwal-86, MSH-36, DH-3/48, NIA Amber and NIA-10 10/8) were tested for physiological characterization under pot house experiment for individual genotypic response to water stress. The variance of analysis shows two-way interaction water stress [Control (normal four irrigations) and terminal drought (Soaking dose) and wheat genotypes (P≤ 0.05). Seven physiological indices, including Proline content, Glycine-betaine, Total sugars, Total chlorophyll, Nitrate Reductase Activity ((NRA), Potassium (K+) content, and Osmotic potential (OP) were used to evaluate the drought tolerance of six wheat genotypes. From the current data it was illustrated that, MSH-36 and DH-3/48 exhibited the tolerance followed by, Khirman and Chakwal-86 by maintaining their osmotic potential and accumulation of higher proline and glycine-betaine content that helpful for plant to enhancing their tolerance under water stress and to maintain their growth and development, whereas NIA Amber and NIA-10 10/8 are the drought sensitive genotypes as they could not maintain their osmotic potential under drought stress environment.

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