This study investigated the effects of improved bark grafting on scion-rootstock healing, growth, and fruiting in low-yield Camellia oleifera forests after top-grafting, aiming to provide technical support for variety improvement.

Four cultivars (‘Huajin’, ‘Huaxin’, ‘Huashuo’, ‘Xianglin 210’) were grafted onto low-yield trees using modified bark grafting. Bud sprouting, wound healing, crown width, shoot length, basal diameter, and yield were monitored over three years.

1) Grafting in mid-June (vs. mid-May) accelerated bud sprouting, increased shoot height, and enhanced branching; 2) ‘Huajin’ and ‘Huashuo’ formed dense callus rings at graft unions by 60 days post-grafting, with wound healing observed in ‘Xianglin 210’ ‘Huajin’ and ‘Huashuo’ by day 75; 3) ‘Huajin’ exhibited superior branching, leaf expansion, and shoot growth in the first year; 4) After two years, graft unions tightened, callus expanded, and ‘Huajin’/‘Huaxin’ showed optimal healing; 5) Three-year-old ‘Huajin’ grafts achieved the largest basal diameter and tree height

The best time to perform high-grafting crown replacement on low-yielding Camellia oleifera forests using the improved bark-inlay grafting technique is mid-June. Grafting with ‘Hua Jin’ and ‘Hua Xin’ as scions shows good results in scion and rootstock healing. ‘Hua Jin’ has a significant advantage in the base diameter of new shoots and tree height growth. Grafting with ‘Hua Xin’ and ‘Hua Shuo’ as scions leads to a relatively higher increase in fruit yield in the first three years. The average fruit yield per tree of the four varieties after three years of grafting reached 8.2 kg, among which the fruit yield per tree of ‘Xiang Lin 210’, ‘Hua Xin’, and ‘Hua Shuo’ was all above 7.5 kg, and that of ‘Hua Jin’ was close to 7.5 kg.