Teste de Condutividade Elétrica para Avaliação da Qualidade de Sementes de Mamona

Abstract

The increasing demand for castor seeds in Brazil has promoted more interest in the development of tests to assess seed lots with superior quality. To investigate the possibility of use of electrical conductivity test for evaluation of castor bean seed quality, ten seed lots from the cultivars AL Guarany 2002 and IAC 80 were used. The seeds were submitted to the bulk and individual conductivity test at four periods of imbibition (6, 12, 18 and 24 hours).The characterization of the lots was carried by the germination test, first count, seedling emergency, initial emergency, index of emergency speed and tetrazolium test. There were also determined the moisture content of the seeds, the imbibition curve and seed sanity. The bulk conductivity test was carried by using plastic cups with 25 seeds each in 75 ml of deionized water, incubated in BOD at constant temperature of 25°C. The determination of the individual conductivity was carried by automatic analyzer of seeds SAD-9000S. In contrast with the determination seed quality by using the individual conductivity test, the bulk conductivity test was efficient in the detection of differences in seed lots quality of castor, being the period of 6 hours the imbibition time indicated for the test.