Identification of affinity of different pumpkin hybrid combinations with cucumber grafting

• In the initial phase, 10 combinations resistant to root-knot nematodes and wilt disease were selected from 38 pumpkin hybrid combinations. • The results showed that the strong seedling index, plant height, stem thickness, root length, number of root tips, and CAT activity of grafted cucumber were higher than those of self-rooted cucumber in ten pumpkin hybrid combinations. • The root activity of nine pumpkin hybrid combinations of grafted cucumber and the SOD activity in the leaves of grafted cucumbers were higher than that of self-rooted cucumber. • The MDA content of seven pumpkin hybrid combinations of grafted cucumber leaves was lower than that of self-rooted cucumber. To study the grafting affinity of different pumpkin hybrid combinations with cucumber, this paper selected ten root-knot nematode-resistant and wilt-resistant pumpkin hybrid combinations as rootstocks for cucumber grafting. Grafting survival rate, growth status of grafted seedlings, root system vitality, enzyme activity, and other indicators were measured. The results showed that among the ten pumpkin hybrid combinations, grafted cucumber seedlings exhibited superior growth indicators and higher CAT activity compared to self-rooted cucumber; The root activity and the SOD activity of nine pumpkin hybrid combinations grafted cucumber were higher than that of self-rooted cucumber; the POD activity of three pumpkin hybrid combinations grafted cucumber was significantly higher than that of self-rooted cucumber; and the MDA content of seven pumpkin hybrid combinations of grafted cucumber was lower than that of self-rooted cucumber. The above results indicated that grafting may reduce membrane lipid peroxidation by increasing the activity of protective enzymes in cucumber, thereby enhancing their resistance and improving their adaptability to a certain extent. The analysis of the membership function showed that the pumpkin hybrid combinations showing good performance before and after grafting were 487–2 × 112–2, 487–2 × LingchuanC1, Renhe-1 × LingchuanC1, and Renhe-1 × Daziwang-24. Analysis of enzyme activities at the junction of the rootstock and the scion indicated that the pumpkin hybrid combinations Fangshan × Renhe-1, 487–2 × 112–2, 487–2 × LingchuanC1, and Renhe-1 × LingchuanC1 grafted cucumber had lower callose synthase activity than other pumpkin hybrid combinations. Comprehensive membership function analysis indicated that the pumpkin hybrid combinations 487–2 × 112–2, 487–2 × LingchuanC1 and Renhe-1 × LingchuanC1 grafted cucumber have excellent grafting affinity advantage.