Survival characteristics of corn seed during storage: II. Rate of seed deterioration

The Ellis-Roberts deterioration model depends on the assumption that the ra te of seed deterioration Ts the same among seed lots of a crop species when stored in identical environments. The rate of deterioration of 11 corn (Ze a mays L.) seed lots from six hybrids was measured during storage in variou s combinations of constant temperatures (20, 30, 40, and 50 degrees C) and seed moisture contents (100, 120, 140, and 160 g kg(-1), fresh weight basis ). The seed-survival curves were constructed by conducting successive germi nation tests at frequent intervals during storage. The rates of seed deteri oration were estimated by probit analysis and differences among seed lots w ere identified by analysis of variance. The deterioration rates were signif icantly different among seed lots in 16 of 21 storage environments when ana lyzing full data sets tan data points) and in 14 of 21 storage environments when using truncated data sets (germination percentages between 5 and 95%) . Both genotype and initial seed quality affected the rate of deterioration with low-vigor seed lots generally deteriorating at a faster rate than hig h-vigor seed lots. The rate of deterioration was greatly influenced by stor age environment and increased with an increase in storage temperature, seed moisture, or both The assumption of a constant rate of seed deterioration in identical storage environments mas not valid for hybrid corn seed.