Germinação e emergência de genótipos superiores de bacurizeiro (Platonia insignis Mart.), oriundos do município de Santa Rita - Maranhão

Abstract

The bacuri tree (Platonia insignis Mart.) is a native tree species of the Eastern Amazon, whose fruits have substantial commercial value. However, seedling production remains constrained by slow and uneven seed germination. In this context, the present study aimed to evaluate seed germination and seedling emergence in five superior genotypes collected from a secondary- vegetation bacuri stand in the Santa Filomena community (Santa Rita, MA). The experiment was conducted in the seedling nursery of the School Farm of the State University of Maranhão, using a completely randomized design. Five replicates of 12 seeds per genotype were used, totaling 360 seeds. Radicle germination parameters were assessed at 10, 20, 30, 40, and 60 days after sowing (DAS). Germination percentage, germination speed index, and mean germination time were calculated. Seedling development was evaluated at 80, 120, 160, 200, and 245 DAS, and emergence percentage, emergence speed index, mean emergence time, and seed mortality rate were determined. Data were subjected to analysis of variance, followed by Tukey’s test at 5% probability. A significant genotype effect was observed for all evaluated parameters. Genotype MTZ-08 exhibited the highest germinative performance, with the greatest germination percentage (95%) and germination speed index (0.19 days⁻¹). Regarding shoot emergence, MTZ-08 also showed the highest mean emergence at 160 DAS (26%), the greatest emergence speed index (0.05 days⁻¹), and the shortest mean emergence time (154 days). At 245 DAS, genotype MTZ-14 reached the highest cumulative shoot emergence (64%), indicating strong final seedling production potential, although with later emergence. In contrast, genotype MTZ-22 displayed the lowest physiological performance, with reduced germination (40%), the lowest germination speed index (0.08 days⁻¹), the lowest emergence at 245 DAS (28%), and the highest seed mortality rate (45%). Overall, the results reveal substantial variability in germination and emergence traits among P. insignis genotypes, suggesting a strong genetic influence on seed physiological vigor. Genotype MTZ-08 showed the best overall performance and stands out as a promising candidate for seedling production and genetic selection programs. These findings underscore the importance of physiological characterization of germplasm from remnant P. insignis populations as a foundation for future breeding and conservation strategies for the species