A Comparative Study of Drought and Excess-Water Tolerance in Vitis coignetiae and Several Table Grapes Grown in Japan

Excess-water and drought tolerance of Vitis coignetiae grapevines were compared against 2 V. vinifera cultivars, Muscat of Alexandria and Rizamat; and 2 hydrids (V. vinifera × V. labrusca), Delaware and Kyoho. Three-year-old cutting vines of each, planted in root zone restricted beds in a plastic house, were tested under water logged and irrigation-withheld conditions starting from early and mid July, respectively. Control vines were irrigated at pF 2.2 of soil water tension. Effects of water logging were firstly observed in V. coignetiae vines where the basal leaves turned dark red after 12 days, and then abscised after 3 weeks. Under 2 weeks of water logged conditions, net assimilation rate (NAR) of the primary leaves decreased signficantly in V. coignetiae and the hybrid cultivars, Kyoho leaves turned yellow 3 weeks after the onset of the treatment and then dried out 4 weeks later. Leaves of Rizamat, Delaware, and Muscut of Alexandria vines exhibited a slight color fading or leaf curling after 4 weeks of irrigation withholding, but these symptoms did not extend thereafter. Leaf NAR and transpiration rate decreased significantly in all tested vines after 10 days of irrigation withholding, though the decrease was rapid in Kyoho vines. These results indicate that V. coignetiae vines have a lower tolerance for water logging than other ciltivars, whereas they have moderate drought tolerance.