Qualidade de sementes de Brachiaria Brizantha cv. Xaraés do campo de produção ao armazenamento

Abstract

In Brazil, pasture growing has great importance, considering Brazilian economy is based on agricultural production, at same time Brazilian pastures takes up most of agricultural areas. The use of high quality seeds is a primary factor for the improvement and renovation of these areas. This study aimed to evaluate the Brachiaria brizantha cv. Xaraés seed quality evolution, at field, bagging process, and at storage. This essay was characterized by five seed collections: the first one was in the field after complete threshing; the second one, after raking the cultural remains of plants before seed harvest; the third one, during mechanized harvesting; the fourth one, during the bagging; and the fifth one collection was in seeds bagged after one month of storage. Evaluated variables were: standard germination test, purity test, blotter test and tetrazolium test. There was a progressive increase in seed germination rate, reaching a maximum of 84% for stored seeds. As the tetrazolium test maintained the same average percentage of 92% from the beginning to the end of collections, it is possible that there has been overcoming seed dormancy during the storage period. Purity rates has increased during this study, reaching 62% in seed stored, value within the legal minimum standards. In relation to health quality, the three major pathogenic fungi identified were Bipolaris sp., Phoma sp. and Curvularia sp., but all those fungi with a tendency to reset rates after one month of seed storage.