Flowering acceleration in native Brazilian tree species for genetic conservation and breeding

Abstract

Grafting and growth retardants are commonly used in breeding programs to stimulate flower production. However, little is known about their effects on Brazilian tree species. The aim of this study was to investigate the vegetative and reproductive development of grafted tree seedlings treated with paclobutrazol (PBZ) and grown under greenhouse or outdoor conditions. Potted seedlings of Jacaranda mimosifolia , Handroanthus heptaphyllus , Swietenia macrophylla , Schinus terebinthifolius , Cariniana legalis , and Hymenaea courbaril were evaluated. Shoot number, length, and circumference as well as flower and fruit numbers were determined at 50 and 90 days after PBZ application. Data were subjected to analysis of variance, and means were compared by Tukey’s test (P ≤ 0.05). Growing conditions influenced the vegetative parameters of seedlings, especially after 90 days. J. mimosifolia and S. terebinthifolius responded positively to flowering induction, and their fruit and flower numbers differed between growing environments. Potted grafts of the six native tree species were successfully grown. Grafting and PBZ application induced early flowering in J. mimosifolia and S. terebinthifolius .