Physiological quality of cowpea seeds for different periods of storage
ABSTRACT The aim of this study was to evaluate physiological quality in the seeds of four cowpea cultivars during nine months of storage. The cowpea cultivars used were BRS Mazagão, UFRR Grão Verde, Pretinho Precoce 1 and BRS Guariba, produced intercropped with cassava in the experimental area of the Centre for Agrarian Science of the Federal University of Roraima, in Boa Vista. After harvest, the seeds were dried, hand cleaned, placed in PET bottles and stored for nine months at a temperature of 23 ºC and a relative humidity of 60% at the Seed Analysis Laboratory of Embrapa Roraima. Data analysis was carried out in a completely randomised design, in a 4 x 4 factorial scheme with eight replications. The physiological quality of the seeds was evaluated at the start of storage, and after 3, 6 and 9 months, for germination, first germination count, 1000-seed weight, moisture, electrical conductivity, speed of emergence, seedling field emergence and water gain. Physiological quality in the seeds of BRS Guariba is influenced by the storage period. Irrespective of storage period, seeds of the Mazagão cultivar show superior physiological quality in relation to the other cultivars. Seeds of the BRS Guariba and Grão Verde cultivars show a reduction in physiological quality after three months of storage.