Effects of Reverse Bud-grafting on Growth and Nutrient Uptake of Rubber Mini-seedling Buddings

Reverse bud-grafting was used for dwarf production. Dwarf of rubber tree could be against wind damage. To investigate the effects of reverse bud-grafting on rubber trees, the elite planting material mini-seedling budding was used to observe the growth and nutrient uptake. The results showed that compared with conventional cis bud-grafting, at nursery stage, reverse bud-grafting had 16.37% more (p<0.05) in leaf whorls, 66.66% more (p<0.001) in rootstock-scion angle, and the diameter of reverse bud-grafting was 23.57% more (p<0.01) in rootstock, 18.31% more (p<0.05) in rootstock-scion, and 18.31% more (p<0.05) in scion, respectively. However, at field stage, the diameter of reverse bud-grafting was 23.25% less (p<0.001) at 3 months, and 11.65% less (p<0.001) at 18 months, than those of cis bud-grafting, respectively. Nutrient uptake might account for growth differences. For scion shoot, reverse bud-grafting was 34.19% less (p<0.001) in N, 16.12% less (p<0.01) in P, and 37.63% more (p<0.01) in C/N, respectively. For rootstock-scion combination, reverse bud-grafting was 10.76% less (p<0.01) in N, 14.05% less (p<0.05) in P, 19.92% more (p<0.01) in K, 30.03% more (p<0.001) in soluble sugar, and 45.94% more (p<0.001) in C/N, respectively. For rootstock, reverse bud-grafting was 39.65% less(p<0.001) in N, 38.11% less (p<0.001) in P, 5.65% less (p<0.05) in K, and 67.31% more (p<0.001) in C/N, respectively. Taken together, bigger diameter of rootstock-scion combination caused by reverse bud-grafting, affected the growth of mini-seedling buddings and nutrient uptake between scion and rootstock.