Reaction of Different Genotypes of Tomato (Solanum lycopersicum) to Drought Stress

12 hybrides of tomato and their parents were evaluated for their response to drought stress in a randomized complete block design with three replications and three irrigation levels (FC, 60%FC, and 40%FC). The studied genotypes were including Kingstone, Petoearly, Bitstoik, LA1607, LA2656, LA2080 and LA1579. Experiments on crossing the genotypes, seedling production and field evaluation, were done in experimental greenhouses and experimental field of Ilam University in 2014-2016. The studied traits consisted of proline, MDA, peroxidase, catalase and ascorbate peroxidase, Relative Water Content (RWC), Chlorophyll a, b and total, electrolyte leakage, total yield, potential yield and single plant yield. The statistical analysis showed that drought stress significantly affected all assessed traits under drought condition. Increase in Proline and MDA content was observed in all genotypes under drought stress. The highest values of proline )31.93 µMgFW-1) was obtained under severe stress in Petoearly× LA2080. RWC, total yield, potential yield, single plant yield, Chlorophyll a, b, catalase and ascorbate peroxidase contents were reduced and proline, electrolyte leakage and peroxidase content were increased by increase in drought stress. Under severe drought stress, the highest amount of total yield (15.74 t.ha-1) was observed in LA2656×Petoearly hybrid, Petoearly line (19 t.ha-1) and LA1579 tester (32 t.ha-1).