Seed Propagation of Carapa amorphocarpa W. Palacios Using Various Treatments of Substrates and Mechanical Seed Scarification in a Nursery in the Andean Area of Northwestern Ecuador

Abstract

Carapa amorphocarpa W. Palacios is a forest species known solely from Cerro Golondrinas in northwestern Ecuador. The species is threatened due to illegal exploitation of its wood and the encroachment of the agricultural frontier. Although information on its ecology and forestry was presented in 2012, there is still very little information available. This study investigated the effects of various pre-germinative treatments on the seed germination and early growth of Carapa amorphocarpa in a nursery. The treatments included combinations of substrates (forest soil alone and forest soil mixed with sand), along with pre-germinative mechanical seed scarification. Through these treatments, the seeds’ germination capacity, growth potential, and survival rates were evaluated in a nursery. Seed germination was found to be cryptocotylar hypogeal, commencing at 41 days and achieving an average of 83.13%. Survival of germinated seedlings was 99.23% at 60 days after germination. Furthermore, a high degree of correlation in growth was observed between basal diameter and plant height (R = 0.94). The mean values for the plants’ basal diameter and total height were 0.91 cm and 50.48 cm, respectively, at 60 days. Plant form was straight with excellent health. These insights offer the potential to enhance species populations, mitigate threat risks, and in the long term, foster sustainable use of Carapa amorphocarpa genetic resources. Moreover, this seed propagation information can be leveraged for other species within the genus exploited for oil extraction from their seeds, thereby broadening knowledge and facilitating sustainable forest resource management.