FIELD EMERGENCE OF SHRUNKEN-2 CORN PREDICTED BY SINGLE-VIGOR AND MULTIPLE-VIGOR LABORATORY TESTS

Poor emergence and seedling vigor are common characteristics of many s weet corn (Zea mays L.) cultivars with the shrunken-2 (sh2) mutant end osperm, A rapid and reliable predictor of sweet corn seed field emerge nce would improve the potential for high quality crops, Field emergenc e of seven sh2 sweet corn cultivars grown at seven environments in Flo rida were correlated with laboratory vigor tests, Factor analysis was used to separate noncollinear vigor tests for subsequent multiple regr ession 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 cond uctivity after 3 h soaking at 25 or 30C (R(2) = 0.90**), soil cold te st (R(2) = 0.90**) 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 p redictors of field emergence, Noncollinear tests including the towel g ermination test at 25C and an alternate temperature stress conductivit y test resulted in the best two factor predictor (r(2) = 0.89**), and with glutamic acid decarboxylase activity (GADA) was the best three f actor predictor (r(2) = 0.93**), The index of conductivity and comple x vigor test (ICS) evaluated seed membrane integrity and potential for pathogen infection, respectively, and can be considered as major fact ors affecting emergence in sh2 sweet corn.