Phenotypic and Genotypic Analyses of Drought Tolerance in Korean and Tunisian Wheat Cultivars

Common wheat (Triticum aestivum L.) and durum wheat (T. turgidum L. subsp. Durum) are major staple food crops in the world. However, their production are limited by environmental stress such as drought. In order to evaluate wheat’s response to drought, a total of 77 common wheat and durum wheat consisted of 19 Korean common wheat, 30 Tunisian common wheat and 28 Tunisian durum wheat were used in this study. Drought stress was applied for 21 days by suspending water application starting at the third leaf-expansion stage, followed by watering for the recovery of wheat until harvesting. Phenotypic parameters such as plant height, leaf length, tiller number, chlorophyll content, days to flowering and dry weight were scored during and after the treatment. Drought tolerance trait index (DTTI) and drought tolerance index (DTI) were calculated and used as criteria for selection of drought tolerance. At the end of treatment, most of the parameters except tiller numbers significantly decreased. Even after re-watering, plant height, leaf length, and dry weight continuously decreased. However, leaf chlorophyll content, and days to flowering of both stressed and non-stressed plants showed no significant differences. A total of 17 drought tolerance related simple sequence repeats (SSR) markers were used to identify genetic distance between Korean and Tunisian cultivars and elucidate possible use of marker systems for drought resistance. The common wheat and durum wheat cultivars formed different clusters for drought tolerance (resistance, moderate resistance, susceptible) using the SSR data. The results obtained in this study could help to increase genetic resources and breeding program for drought tolerance.