Should growers consider switching from full-season to shorter-season hybrids? Not necessarily. In most situations, Thomison notes, full-season hybrids will perform satisfactorily even when planted as late as May 20-25. Results of studies evaluating hybrid response to delayed planting dates indicate that hybrids of varying maturity can "adjust" their growth and development in response to a shortened growing season – requiring fewer units of heat than the same hybrid planted in late April or early May.

However, there are other factors concerning hybrid maturity that need to be considered. While a full-season hybrid may still have a yield advantage over shorter-season hybrids planted in late May, it could have significantly higher grain moisture at maturity than earlier-maturing hybrids if it dries down slowly. Also, there are many short- to mid-season hybrids with excellent yield potential. As a result, if growers think they may end up planting in late May, they should consider the drydown characteristics of their various hybrids.