Dormência e armazenabilidade de sementes de capim-gordura

the african grass species, melinis minutiflora, which was an important forage species in the brazilian cerrado region for around two centuries, is nowadays considered an important weed in this region. the present study aimed to evaluate seed dormancy and viability during storage, aspects that could affect species dissemination. seeds of the cultivars roxo and cabelo-de-negro stored under laboratory conditions in brasília-df, brazil, were tested periodically, both at alternating temperatures of 20-30 oc (16/8 hours), with white fluorescent light during the highest temperature, plus potassium nitrate at 0.5%, and at 25 oc in darkness and in water. recently-harvested seeds of both cultivars showed approximately 100% viability and a high primary dormancy level. seed viability remained high for around three years (at least 90%), and even after eight years of storage under these conditions some seeds remained viable. at alternating temperatures, the average germination period is 4.3 days for the roxo cultivar and 4.4 days for cabelo-de-negro. seed dormancy was completely overcome after 3.8 years of storage. the high seed viability, dormancy and germination speed observed in this study help to explain the success of this species in colonizing new areas.