Biotecnologia, silvicultura e importância socioeconômica do umbuzeiro no semiárido brasileiro

Abstract

The umbu tree (Spondias tuberosa Arruda) is a fruit species native to the Caatinga, with high ecological, socioeconomic and cultural importance for the Brazilian semi-arid region. Despite its potential for food production, income generation, biodiversity conservation and seedling production, the species still presents limitations related to propagation, dormancy of dispersal units, initial establishment and the scarcity of consolidated biotechnological and silvicultural protocols. In this context, this thesis aimed to evaluate biotechnological, silvicultural and socioeconomic aspects related to the umbu tree, in order to support strategies for propagation, seedling production, conservation and sustainable use of the species. Article 1 addressed the Anacardiaceae family, with emphasis on the diversity, uses and socioeconomic importance of native species for the Brazilian semi-arid region. The study highlighted the umbu tree as a strategic species of the Caatinga, due to its food, cultural, economic and environmental value. Article 2 presented a systematic review on umbu tree propagation, gathering studies published between 1991 and 2025. The results showed advances in seed technology, mineral nutrition, seedling production and vegetative propagation, but also gaps related to micropropagation, germplasm conservation and the standardization of vegetative propagation protocols. In Article 3, the effects of mother trees and provenances on dispersal unit biometry, seedling emergence, and initial seedling growth were evaluated. Differences were more evident in biometric attributes and emergence variables, while initial growth showed less pronounced or occasional responses among mother trees.. In Article 4, seedling production was evaluated under different light conditions and doses of controlled-release fertilizer. Moderate doses favored seedling growth and quality, whereas high doses compromised the morphological balance of the plants. In Article 5, the reuse of culture medium residues was evaluated as an alternative for seedling production. The application of these residues showed potential to promote initial growth and seedling nutrition, especially at specific application periods, suggesting their potential as a sustainable input for nursery seedling production.. In Article 6, the in vitro germination of seeds after endocarp removal was investigated, considering different mother trees, provenances and culture media. The removal of this structure favored germination and reduced limitations associated with slow and uneven emergence, as well as contamination of dispersal units. In Article 7, strategies for in vitro culture and micropropagation of the umbu tree were evaluated, involving different culture conditions, medium compositions, plant growth regulators and explant types. The results indicated distinct responses according to the treatment, reinforcing the need for specific adjustments for the establishment, multiplication and in vitro development of the species. Overall, the results demonstrate that the propagation and seedling production of the umbu tree depend on the integration of mother tree selection, management of dispersal units, removal of barriers imposed by the endocarp, adjustments in in vitro culture, and appropriate silvicultural practices.