Correlação entre locais de produção e a qualidade de sementes de urochloa spp. (sin. Brachiaria spp.) em função do manejo e armazenamento

Abstract

As tropical forage seeds are not subject to intensive genetic improvement by humans and exhibit long and variable flowering periods depending on the species or cultivar, assessing the longevity of seed lots harvested in different production areas is an essential tool for seed companies. The present study aimed to collect and evaluate information from different production fields of five (5) Brachiaria cultivars: Urochloa brizantha cv. BRS Piatã, Urochloa brizantha cv. Marandu, Urochloa brizantha cv. MG-5 Vitória, Urochloa humidicola cv. Tully, and Urochloa ruziziensis cv. Kennedy. Samples obtained from each production field were physically and physiologically evaluated at three distinct time points and storage conditions: initially; after six months of storage under ambient conditions; and after six months of storage under short-term germplasm storage conditions (10 °C / 30% RH). Following the collection of the results, correlations were established between the parameters observed in the production fields and selected analytical parameters and the performance of the seed lots after the storage period. The results demonstrated that seed physiological quality and seed storage potential are determined by the interaction between weather conditions and crop management. Overall, higher solar radiation and suitable thermal conditions favored seed vigor, whereas high altitude, dry periods, and temperatures outside the optimal range reduced seed quality. Balanced nutrient management, combined with soil correction, was a crucial factor for better results, whereas unbalanced management practices, particularly for nitrogen utilization, impaired physiological quality. Regional differences were evident, with better performance of Urochloa brizantha cultivars produced in Mato Grosso do Sul, Urochloa humidicola in Minas Gerais, and Urochloa ruziziensis in the municipality of Jaborandi, Bahia. The conclusion is that seed quality and longevity depend on integrated management adapted to the environment and genetic material, making it essential to jointly consider field conditions and physiological attributes to optimize the production, storage, and commercialization of seed lots.