Dehydration Rate after Solid Matrix Priming Alters Seed Performance of Shrunken-2 Corn

Abstract

In a test to overcome poor seed germination and seedling vigor of sweet corn (Zea mays L.) seeds carrying the shrunken-2 (sh2) mutant endosperm, primed seeds of two sh2 sweet corn cultivars—Crisp N'Sweet 711 (CNS-711) and How Sweet It Is (HSII)—were redried at 15, 20, 30, or 40C and 25% relative humidity after solid matrix priming (SMP). The dehydration rate was significantly lower in `CNS-711' than `HSII' at all temperatures. In both cultivars, the drying temperature after SMP was critical for seed performance. Primed seeds with a higher dehydration rate (dried at 30 or 40C) had better seed vigor, greater field emergence and seedling vigor, lower leachate conductivity and imbibition rate, and a higher respiration rate and glutamic acid decarboxylase activity than primed seeds redried at the lower temperatures or control seeds. Increased incidence of pathogen growth was observed on seeds dried at 15 and 20C relative to those dried at 30 or 40C, probably as a consequence of greater leakage from the seeds at a lower redrying temperatures. Lack of tolerance to dehydration at 15 and 20C was another factor adversely affecting the seeds redried at low temperature. A more rapid dehydration rate at a higher temperature after priming sh2 sweet corn improved many of the physiological characteristics used to measure seed quality and the subsequent emergence and vigor of the seedlings under field conditions.