Effects of Rootstock on Fruit Yield and Quality of Hydroponically Cultivated Grafted Cucumber under NaCl Stress

With the aim of screening salinity resistance rootstock in order to improve salt tolerance of cucumber, Cucurbita moschata hybrid '360-3x112-2', which showed strong salt tolerance in our previous study, and commercially used C. ficifolia were tested as rootstocks for cucumber cultivar 'Jin-chun No. 2' at an early adult stage in hydroponic culture under both 80 mmol.L-1 NaCl stress and non-NaCl stress conditions. Under non-NaCl stress conditions, grafted cucumber plants showed higher average fruit weight and similar plant yield compared to non-grafted plants. Fruits from '360-3x112-2' hybrid rootstock showed comparable flavor, taste and nutrient contents to those of non-grafted plants, both of which out-preformed plants grafted with C. ficifolia rootstock. NaCl stress showed immense impact on both grafted and non-grafted cucumber plants on the effects such as lower average fruit weight, lower early phase plant yield, higher abnormal fruit rate and fruit with inferior flavor. NaCl stressed plants also produced fruit with a lower content of vitamin C, free amino acids, soluble sugar and water but higher contents of cellulose and titratable acids. NaCl stress conditions the least impact on cucumber plants grafted on '360-3x112-2' hybrid, demonstrating that '360-3x112-2' hybrid has the potential to be used as a qualified cucumber rootstock in production.