Effect of seed shape and size on germination of corn (Zen mays L.) stored under adverse conditions

Flat and round seeds of hybrid corn B-15 of three seed sizes were stored at 75% and 85% relative humidities (RH) and 25 degrees C to evaluate under co mmon tropical storage conditions the effect of seed shape and size on seed viability. For seed stored 120 days at 75% RH., with seed moisture contents from 13.6 to 13.8%, the germination percentages of large, medium and small flat seeds, were 85%, 75%, and 80%, while those of the large, medium and s mall round seeds were 59%, 31% and 28%, respectively. At 85% RH, the averag e seed moisture content increased while seed viability decreased very rapid ly, bur the viability behavior was the same as in the 75% RH in relation to seed shape and size. Ar 30 days of storage, with seed moisture contents of 15.3-15.6%, the germination of large, medium and small flat seeds was 93%, 86% and 84%, respectively, while the round seeds had a germination of 86% for large seeds, 57% for medium seeds and 48% for small seeds. At 60 days, with seed moisture contents of 16.0-16.2%, seeds were heavily invaded by st orage fungi and aged rapidly, presenting very low germination percentages, from 2 to 8%, for all type of seeds. According to these results, it seems t hat flat and large maize seed of the studied maize hybrid maintained a high er viability during storage than round and small seed.