Combined Effects of Drought and Low Temperature on Germination and Seedling Growth of Melon Cultivars

The study aimed to determine the effects of drought (0.0, -2.0, -4.0, and -6.0 bar PEG 6000) and low temperature (18°C) on the germination and early seedling growth of three melon cultivars (Kırkağaç 589, Hasanbey 1, and Toros Sarıbal). Germination percentage, mean germination time, germination index, root length, shoot length, fresh and dry weight of the seedling, and vigor index of the melon cultivars were investigated. The results showed significant effects of low temperature and drought stress on the germination and seedling growth of melon cultivars. As temperature decreased and drought increased, the germination percentage decreased, and mean germination time was delayed. Drought stress led to a decrease in germination percentage, index, and all investigated seedling growth parameters, while the response of melon cultivars to drought stress varied. Seedling growth was more affected by low temperature than germination. Low temperature decreased germination percentage from 87.2% to 63.7% and seedling fresh weight from 140 mg/plant to 64 mg/plant. Each increase in drought levels resulted in a decrease in germination and seedling growth parameters of melon cultivars. Any seedling growth was not observed in Hasanbey 1 and Toros Sarıbal at -6.0 bar at 18°C. Melon cultivars showed different levels of tolerance to drought stress during germination and seedling growth stages, while they could maintain it up to -4.0 bar. It was concluded that Kırkağaç 589 germinated and grew better under drought stress at both optimum and low temperatures.