Assessment of Iranian Rainfed and Seedy Watermelon Landraces as Potential Rootstocks for Enhancing Drought Tolerance

چکیده مقاله

We conducted this study over the course of two consecutive growing seasons to evaluate the
response of watermelon (Citrullus lanatus (Thunb.) Matsum. et Nakai cv. Crimson Sweet) to
grafting onto three Iranian rainfed and seedy watermelon landraces collected from Khaje, Sabzevar, and Ashtian, along with ‘Shintoza’ (Cucurbita maxima × Cucurbita moschata) seedlings as a rootstock for watermelon. Soil moisture content [percentage of field capacity (FC)] was determined by time domain reflectometry (TDR). Irrigation was applied in three different levels based on FC as 0.8FC-FC, 0.6FC-0.8FC and 0.3FC-0.6FC by furrow irrigation method. Yield, shoot dry weight, fruit quality, chlorophyll index, phenolic compounds, relative water content (RWC), electrolyte leakage, and proline concentration were measured at the end of both growing seasons. The results showed that the highest fruit yield (9.4 kg) and shoot dry weight (390.8 g) were obtained in watermelons grafted onto Shintoza rootstock in 0.8FC-FC. The lowest fruit yield (1.4 kg) and shoot dry weight (55.6 g) were observed in un-grafted controls and in 0.3FC-0.6FC. Fruit quality in watermelons grafted onto Shintoza rootstock was significantly different compared to the other grafting combinations and the un-grafted control. Chlorophyll index, phenolic compounds, RWC, electrolyte leakage, and proline were significantly affected by irrigation regimes. Shintoza and Sabzevar grafting combinations showed high levels of chlorophyll index, phenolic compounds, and RWC as compared to un-grafted plants and Ashtian grafting combination.