Drought is one of the most important environmental factors that causes unfavorable conditions for plant growth and development, affects all morphological, physiological, biochemical and metabolic aspects of plants and finally decreases crop production, particularly in arid and semi-arid regions worldwide. The reduction of plant yield due to drought stress conditions, depends on the severity and duration of the stress. In order to estimate general and specific combining ability and to determine the gene action under two moisture conditions for agronomic traits in maize, 13 inbred lines obtained from CIMMYT’s germplasm were crossed to A679, K166B, K18 and MO17 testers, using line × tester genetic design. A total of 71 genotypes involving 52 hybrids obtained from line × tester crosses, 17 inbred lines (13 inbred lines from CIMMYT’s germplasm and four testers) and also two check hybrid cultivars (KSC704 and KSC705) were evaluated, separately under two irrigation regimes. The irrigation regimes were control (100% of plant water requiremen) and irrigatio based on 65% of plant water requirement. The experiments were conducted over two growing seasons in 1393 and 1394 at Islamabad Research Center of Kermanshah, Agricultural and Natural Resources Research and Training Center, using randomized complete block design with three replications. In order to evaluate genetic variation in the germplasm used in this study, 25 SRAP markers were also used. Then according to UPGMA method, principal component analysis and cluster analysis were used to Key words Maize, Line× Tester Analysis, Combining ability, Genetic Diversity, Heterosis, SRAP Marker.
