Switching Hybrid Maturities for June Planting Dates

By:  Alexander Lindsey, Rich Minyo, Allen Geyer, and Peter Thomison, Ohio State University

Farmers who still anticipate planting corn for grain production should review their hybrid maturities to minimize the risk of corn not maturing safely prior to a killing fall freeze. We would encourage the use of the Corn GDD Tool to select “safe” hybrid maturities for late planting (http://www.kingcorn.org/news/timeless/HybridMaturityDelayedPlant.html).

Although they are not planted as widely as our commonly grown maturities, hybrids with relative maturities of 100-104 day maturity are likely to achieve physiological maturity if planted by mid-June throughout most of the state. There is limited information on the agronomic performance of hybrids with maturities less than 100 days. Since these “ultra-early” hybrids were not developed to be planted in Ohio, they are regarded as less adapted to growing Ohio conditions and more susceptible to disease and stalk quality problems. Because of their questionable yield potential, ultra-earlies are typically not recommended in late planting situations.

In recent trials conducted at OSU in 2016-2017, ultra-early hybrids (90-100 day) were compared to more common CRM hybrids (104-109 day) for agronomic performance. Planting dates were May 23 and June 2 in Crawford County in 2016 and 2017, and May 23 in Wayne County in 2017. All hybrids were harvested on the same date within a site each year. Growing conditions were very favorable for corn production at these sites.

While yield and return were greatest for the 104-109 day hybrids, the return per acre was similar to the 96-100 day hybrids statistically (as indicated by the asterisks) due mainly to discounts on the 104-109 day hybrids from low test weights and high harvest moisture. The performance of the 90-95 day lines was consistently below the other groups tested but still produced substantial yield. In 2018, when planting dates were mid-May at each location, the yield and return were greater with the 104-109 day hybrids compared to the ultra-early hybrids. When considering changes to relative maturity for late planting, this may help in the decision-making process. Earlier maturity hybrids may incur less drying costs and have higher test weights, but may have a slight yield disadvantage compared to the 104-109 day hybrids. However, these results and observations are based on limited test data that may not apply across a wider range of production environments, especially those outside northcentral/northeastern Ohio.

We would strongly encourage those producers to consult with their seed company agronomist before changing to hybrids with a relative maturity less than 100 days. Check hybrid disease ratings for foliar diseases (esp. gray leaf spot and northern corn leaf blight), stalk rots and ear rots as well as dry-down characteristics.