Storage of seeds of maize and sorghum cultivars with different environmental resistances

Abstract

Seeds of the maize (Zea mays L.) cultivars IAC Maya, IAC Maya Latente, and Hmd 7974, and sorghum (Sorghum vulgare L., cv. Sart) were stored under controlled conditions of 30ºC/75% RH, 30°C/55% RH, 30ºC/33% RH, 20ºC/75% RH, 20ºC/55% RH, and 20ºC/33% RH, and under noncontrolled storage conditions at Campinas, Ribeirão Preto, and Pariquera-Açú, in the State of São Paulo, Brazil. The gradual deterioration of the seeds was evaluated by standard germination tests conducted at the beginning of storage and at every four months for a total period of 48 months. The speed of deterioration of the seeds was directly related to the temperature and the moisture content in equilibrium with the relative humidity of the several storage environments. The best suited controlled conditions for maintaining the longevity of the seeds were 20ºC/33% RH and 20ºC/55% RH. The Campinas region was more favorable than Ribeirão Preto for storing the seeds; Pariquera-Açú showed to be inadequate for this objective. The longevity of the maize hybrid 'Hmd 7974' seeds was superior to those of the other cultivars, including that of sorghum. The "latent" factor seems to have conferred more tolerance to storage environment to the 'IAC Maya Latente' seeds, when compared to those of the 'IAC Maya'.