Análise de germinação em sementes de feijão caupi oriundas de Picos-PI

Abstract

This study aimed to evaluate the germination and seed vigor of four local varieties of cowpea (Vigna unguiculata L. Walp), sourced from the Chapada do Mocambo community in Picos, Piauí, in order to contribute to the sustainable management of this crop in the region. Germination was analyzed using Petri dishes in a completely randomized design (CRD) with five replications, with seeds kept in a B.O.D. chamber for seven days. The following variables were evaluated: germination rate, germination speed index (GSI), mean germination time (MGT), and first germination count (FGC). Seed vigor was assessed using the tetrazolium test on 20 seeds per variety. In parallel, pathogenic microorganisms present on the seeds were identified and counted microscopically after incubation in B.D.A. medium, and seedling emergence in sand substrate was evaluated on the 6th and 15th days after sowing. The results did not indicate significant differences among the varieties for germination rate, MGT, or coefficient of germination velocity (CGV). However, significant differences were observed for the GSI and FGC, with the Santo Inácio (V3) and Chumbinho (V4) varieties standing out for their faster and more uniform germination. In contrast, the Canapú (V2) variety showed delayed and low germination rates, despite presenting 100% viability in the tetrazolium test, indicating that viability does not always reflect actual germination performance. Microbiological analysis revealed the presence of pathogenic fungi from the genera Fusarium, Colletotrichum, and Aspergillus, with higher incidence in the Sempre Verde (V1) and Canapú (V2) varieties, possibly compromising the initial seed performance. The sand substrate tests confirmed these observations, highlighting discrepancies between seed viability and actual germination. It is concluded that careful selection of seeds with greater vigor and health is essential to optimize productivity and sustainability in cowpea cultivation in the region, emphasizing the importance of phytosanitary control and the adoption of proper storage and seed treatment practices to ensure better germinative performance.