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Agronomic Crops Network

Ohio State University Extension


Days to Maturity Rating System

The most common maturity rating system is the days to maturity system. This system does not reflect actual calendar time between planting and maturity―a 106-day hybrid, for example, does not actually mature 106 days after planting. A days to maturity rating is based on relative differences within a group of hybrids for grain moisture at harvest. A one day maturity difference between two hybrids is typically equal to a 1/2 to 3/4 percentage point difference in grain moisture. For example, a 106-day hybrid would be, on average, 3 to 4.5 points drier than a fuller season 112-day hybrid if they were planted the same day (6 days multiplied by 0.5 or 0.75). 

The relationship between days to maturity and kernel moisture is usually dependable when comparing hybrid maturities within a single seed company. However, because there are no industry standards for the days to maturity rating system, grain moisture comparisons of similar hybrid maturities from different seed companies may vary considerably. Days to maturity ratings are satisfactory for pre-season hybrid maturity selection when length of the growing season is usually not an issue. For delayed planting or replanting hybrid selection needs, growers need more absolute descriptions of a hybrid’s growing season requirements to manage the risk of a killing fall frost to late-planted corn.