Effect of priming temperature on storability of primed sh-2 sweet corn seed

Priming offers a means to raise seed performance in many crop species, but the longevity of primed seed is generally decreased. The exact causes of the more rapid deterioration of primed seed are still not established. This study evaluated the effects of priming and storage temperatures on germination and antioxidative activities of sweet corn seed (Zea mays L.) carrying the shrunken-2 (sh-2) gene. Seed were solid-matrix primed in moistened vermiculite at 10, 15 or 20degreesC for 36 h, then air-dried to near original moisture level. Primed seed were stored at 25, 10, or -80degreesC for up to 12 mo. Solid-matrix priming improved germination, reduced lipid peroxidation, enhanced antioxidative activities, and increased seedling growth. Seed longevity was decreased when 20degreesC-primed seeds were stored at 25degreesC for 12 mo. Seed primed at 10 and 15degreesC had superior viability and vigor responses compared with nonprimed control seeds when they were stored at 25degreesC for 12 mo. Reduced storability of the 20degreesC-primed seeds was attributable to enhanced peroxidation and decreased antioxidative activities. Storage at 10 or -80degreesC extended the storability of matrix primed sh-2 seed for at least 12 mo. Enhanced antioxidative activity plays a role in maintaining the viability and vigor responses of solid matrix primed seed stored at cool (10degreesC) or subzero (-80degreesC) temperatures. Moreover, 10 or 15degreesC-primed sh-2 seed can retain viability for 12 mo, provided that the primed seed is stored at 10degreesC.