Influence of Harvest, Processing, and Substrate in the Germination of Dalbergia nigra Seeds

Abstract

Dalbergia nigra is a Brazilian native species with relevant economic and ecological roles. Due to its indiscriminate exploration is an endangered species. Besides the great demand for seedling production, only a few aspects of D. nigra germination have been explored. Thus, this study aimed to determine how harvesting immature fruits, fruits processing, and substrate could influence Dalbergia nigra germination process. Five thousand immature, and five thousand mature fruits evenly distributed between two replicas of each of tree 3 treatments; integral fruits, fruits with edges cut, and direct seed sowing in vermiculite. Seeking to evaluate substrate influence over germination, 252 seeds were strewed in the prepared organic substrate. No fruits harvested in visually green appearance did germinate under any of treatments. Integral fruits and cut procedure presented the same time for the first germination, almost two times the amount observed to direct seeds sowing. Besides that, the germination rate was not statistically affected. We found that different substrates also influence the germination pattern, as seen to seed processing when using vermiculite as a substrate, germination starts earlier but the germination rate was not statistically affected. Harvest of Dalbergia nigra green fruits is not an adequate procedure seeking seedling production. The reduction on germination time and better seedling quality, indicate that direct seed sowing procedure is adequate seeking seedling production. Vermiculite substrate gave better results, reducing the time required to germination process. Besides that, this substrate did not affect the germination rate during this study period.