DEHYDRATION RATE AFTER SOLID-MATRIX PRIMING ALTERS SEED PERFORMANCE OF SHRUNKEN-2 CORN

In a test to overcome poor seed germination and seedling vigor of swee t corn (Zea mays L.) seeds carrying the shrunken-2 (sh2) mutant endosp erm, primed seeds of two sh2 sweet corn cultivars-Crisp N'Sweet 711 (C NS-711) and How Sweet It Is (HSII)-were redried at 15,20,30, or 40C an d 25% relative humidity after solid matrix priming (SMP). The dehydrat ion rate was significantly lower in 'CNS-711' than 'HSII' at all tempe ratures. In both cultivars, the drying temperature after SMP was criti cal for seed performance. Primed seeds with a higher dehydration rate (dried at 30 or 40C) had better seed vigor, greater field emergence an d seedling vigor, lower leachate conductivity and imbibition rate, and a higher respiration rate and glutamic acid decarboxylase activity th an primed seeds redried at the lower temperatures or control seeds. In creased incidence of pathogen growth was observed on seeds dried at 15 and 20C relative to those dried at 30 or 40C, probably as a consequen ce of greater leakage from the seeds at a lower redrying temperatures. Lack of tolerance to dehydration at 15 and 20C was another factor adv ersely affecting the seeds redried at low temperature. A more rapid de hydration rate at a higher temperature after priming sh2 sweet corn im proved many of the physiological characteristics used to measure seed quality and the subsequent emergence and vigor of the seedlings under field conditions.