Reproductive phenology of Araucaria angustifolia in Brazil

Abstract

The study of reproductive phenology is important in order to determine the proportion of individuals that contributes to the effective gamete pool in a population and to support programs on pollen and seed collection for use in conservation and breeding programs. In araucaria (Araucaria angustifoliaBert. (O. Ktze.), more intensive studies on reproductive biology and phenology are necessary to elucidate the reproductive aspects in different regions. Field observations in an araucaria provenance test planted in Southern Brazil were recorded. The observations were taken when the stand was between 14 and 16 years old. The results showed that its reproductive cycle is relatively long. The most critical stages, including pollination, occur between September and December and the less critical between May and July, when the temperatures are lower. Pollination occurs during a short period and is significantly variable among trees and from year to year. The proportion of sexually mature trees was small at the time of assessment and this limited the effective population size. In spite of the young age of stand, there were significant differences in seed production among provenances. Further observations are necessary encompassing more advanced ages.