SEED MATURITY INFLUENCES GERMINATION AND VIGOR OF 2 SHRUNKEN-2 SWEET CORN HYBRIDS

The objective of this study was to examine seed maturity at harvest as it relates to seed vigor in two commercial shrunken-2 (sh2) sweet corn hybrids (Zea mays L. var rugosa Bonaf., cvs. Florida Staysweet, Crisp N' Sweet 710). Seed harvest began at 0.76 g H2O/g fresh weight in 1987 and at 0.70 g H2O/g fresh weight in 1988 and 1989, and was continued at gradually declining moisture levels until frost. In five different tests of seed performance, seed of 'Florida Staysweet' (FLASS) harvested between 0.23 to 0.57 g H2O/g fresh weight in 1987 possessed the highest seedling vigor. In 1988 and 1989, maximum vigor was achieved by FLASS seed harvested from 0.40 to 0.60 g H2O/g fresh weight and 'Crisp N' Sweet 710' (CNS) seed harvested from 0.45 to 0.65 g H2O/g fresh weight. Standard germination test, seedling growth cold test (SGCT), and seed leachate conductivity provided the most consistent results to determine optimum seed maturity. Seed weight was not as reliable an indicator of seed vigor in 1988 and 1989 as it was in 1987, and endosperm and embryo weights did not correlate with seedling vigor in any year.