Growth, Yield, and Fruit Quality of Own-Rooted ‘Irwin’ Mango Trees Propagated by Air Layering in Pot Culture

To investigate the practicality of using own-rooted trees in pot culture, the growth, yield, and fruit quality of pot-planted ‘Irwin’ mango trees, propagated by air layering versus grafting, over an 11-year period after planting were measured. The trunk diameter of the own-rooted trees propagated by air layering was significantly smaller than that of the grafted trees propagated by conventional methods until six years of age, after which there was no significant difference between the two tree types. The trunk diameter of the own-rooted trees was significantly greater than that of the scion diameter of the grafted trees after seven years of age. The total length of green branches was significantly longer in the own-rooted trees than in the grafted trees after nine years, and the number of leaves was significantly greater on the own-rooted trees than the grafted trees after six years. The height of the own-rooted trees was 35 cm shorter than that of the grafted trees. The fresh and dry weights of the leaves, green branches, thick branches, scaffold branches, and fine roots of the own-rooted trees were significantly greater than those of the grafted trees. However, the fresh and dry weights of the trunks and thick roots of the own-rooted trees were significantly smaller than those of the grafted trees. The weights (fresh and dry) of the aboveground parts of whole own-rooted trees were significantly greater than those of the grafted trees, but the weights of the underground parts did not differ significantly between the two tree types. The T-R ratio (the weight of the aboveground part of the tree excluding the leaves/the weight of the underground part of the tree) of the own-rooted trees was significantly greater than that of the grafted trees. The yield per tree of the own-rooted trees was significantly lower than that of the grafted trees for two years after fruiting; however, this difference resolved after 10 years. The average yield per unit land area over nine years was 2.46 kg·m⁻² for own-rooted trees and 2.32 kg·m⁻² for grafted trees. The numbers of fruits per tree did not differ significantly between tree types, except during years 4 and 5. The average fruit weight did not differ significantly between the tree types up to nine years, with one exception in year 5. However, the average fruit weight of the own-rooted trees was significantly greater than that of the grafted trees after 10 years. Fruit quality did not differ significantly between the two tree types. Since the height of the own-rooted trees was shorter, and their growth and yield were equal or greater than those of the grafted trees, pot culture using own-rooted trees of ‘Irwin’ mango appears to be highly beneficial.