Supersweet (sh2) and sugar enhanced (se) types of sweet corn have become increasingly popular as they are sweeter and have superior storage potential relative to the standard sweet (su) types. However, the high sugar content in the seed of the sh2 and se types may adversely affect their germination and emergence, particularly in cool, wet soils. Researchers at Clemson University have recently compared the germination characteristics of a range of su, se and sh2 varieties over soil temperatures ranging from 11-30 oC. In general, the standard su types germinated 1-2 days earlier than the se and sh2 types, particularly at the lower soil temperatures. Similarly, the lowest soil temperature to produce maximum germination was several degrees cooler for the su types than the higher sugar types. However, the most vigorous se and sh2 varieties performed as well at low temperatures as the best su types. Varieties which performed well at low soil temperatures, often did relatively poorly at higher temperatures and visa-versa. It appears that each corn variety has a characteristic optimum set of germination conditions. Ideally growers will time planting to coincide with these conditions. This study shows that generalizations about differences in germination potential between the various types of sweet corn are not really valid, at least at soil temperatures above 11 oC. It would be interesting to test the se and sh2 types at the lower soil temperatures commonly encountered by Saskatchewan growers of sweet corn.
Source : Hassel, Dufault and Phillips (2003). Low-temperature germination response of se, se and sh2 sweet corn cultivars. HortTechnology 13: 136-