Qualidade fisiológica de sementes de Megathyrsus ma-ximus produzidas sob diferentes condições edafoclimáticas, de manejo e armazenamento

Abstract

The physiological quality of tropical forage crop seeds is important for pasture esta-blishment and productivity. The objective of this study was to evaluate the physiolo-gical quality of Megathyrsus maximus seeds produced in different fields and subjec-ted to various storage conditions, taking into account soil, climate, and management variables. Batches of the M. maximus × M. infestum hybrid and the cultivars ‘Mas-sai,’ ‘MG-12 Paredão,’ ‘Miyagui,’ and ‘Mombaça’ were analyzed. Physical purity was determined upon receipt of the samples. Other evaluations included moisture con-tent, viability by the tetrazolium test, germination, germination rate index, thousand-seed weight, electrical conductivity, hydrogen peroxide content, and crude protein. The samples were evaluated at the initial stage and after six months of storage at room temperature and under refrigeration. The data were analyzed using analysis of variance and multivariate analyses. Variability was observed among the lots, along with distinct responses to storage conditions. In some lots, germination increased after storage, particularly in ‘Massai’ and ‘Mombaça,’ while refrigerated storage was associated with better maintenance of viability in some of the samples. Multivariate analyses revealed associations between physiological attributes, environmental va-riables, and management practices, with patterns that varied across the evaluated fields. Since these analyses identify associations, they do not allow for the attributi-on of an isolated causal effect to these factors. The results indicate that seed quality should be evaluated by considering both the production environment and storage conditions together.