Response of Ginkgo Cropping to Plant Growth Regulators Applied during the Flowering Period

The female ginkgo trees were treated with paclobutrazol,B₉,GA₃,GA₃+6 BArespectively during flowering period. The results show that paclobutrazol and B₉ improved seed set and increased the flowers in next year.GA₃ and GA₃+6 BAincreased seed weight, across and vertical diameter of seed but didn't improve seed set.Increased seed yield obtained from the paclobutrazol may result from reduced vegetative growth of trees and decreased flower and seed drops.