Field Emergence of shrunken-2 Corn Predicted by Single- and Multiple-vigor Laboratory Tests

Poor emergence and seedling vigor are common characteristics of many sweet corn (Zea mays L.) cultivars with the shrunken-2 (sh2) mutant endosperm. A rapid and reliable predictor of sweet corn seed field emergence would improve the potential for high quality crops. Field emergence of seven sh2 sweet corn cultivars grown at seven environments in Florida were correlated with laboratory vigor tests. Factor analysis was used to separate noncollinear vigor tests for subsequent multiple regression models. The best single predictor test (R 2 = 0.93 *** ) was an index based on leachate conductivity and germination percentage after a complex stress vigor test involving incubation at 15C. Leachate conductivity after 3 h soaking at 25 or 30C (R 2 = 0.9W *** ), soil cold test (R 2 = 0.9 *** ), alternate temperature stress conductivity test (R 2 = 0.88 *** ), standard germination test at 30C (R 2 = 0.88 *** ), and an index involving incubation at 25C (R 2 = 0.88 *** ) were also good predictors of field emergence. Noncollinear tests including the towel germination test at 25 C and an alternate temperature stress conductivity test resulted in the best two factor predictor (r 2 = 0.89 *** ), and with glutamic acid decarboxylase activity (GADA) was the best three factor predictor (r 2 = 0.93 *** ). The index of conductivity and complex vigor test (ICS) evaluated seed membrane integrity and potential for pathogen infection, respectively, and can be considered as major factors affecting emergence in sh2 sweet corn.