What is CRM (Comparative Relative Maturity)?
A CRM value is set by comparing the kernel moisture or physiological maturity timing of a variety with reference hybrids; it does not show the actual number of days from sowing to harvest. Of two varieties rated CRM 118 and CRM 120, for example, the second matures slightly later under the same conditions.
CRM is most common in North America. When it is given alongside the FAO classification used widely in Europe and Türkiye, varieties can be compared on both scales. There is no single conversion table between the two scales that applies to every seed company.
Why does it matter when choosing seed?
Varieties in the same FAO group can still differ in maturity. The CRM value helps rank varieties within a group more finely.
CasSeed varieties related to this topic
The relevant characteristics are listed on each variety’s technical sheet.
FAO 700 · CRM 120 · Grain and silage maize seed
A late-maturity grain hybrid with fast dry-down and outstanding standability.
FAO 700 · CRM 118 · Grain and silage maize seed
A flinty red-grained hybrid with high protein and complete tip fill.
FAO 700 · CRM 120 · Grain and silage maize seed
A widely adapted grain hybrid with high test weight, suited to wider spacing.
FAO 700 · CRM 118 · Grain and silage maize seed
Complete tip fill, high test weight and a hybrid that rewards denser planting.
FAO 650 · CRM 117 · Grain and silage maize seed
Broad ears and a strong stalk — a mid-late hybrid for both grain and silage.
Related terms
FAO maturity group
The FAO maturity group is a numerical scale that classifies maize varieties by the time they need to mature; the higher the number, the later the variety matures.
Physiological maturity (black layer)
Physiological maturity is the growth stage at which maize kernels reach maximum dry matter accumulation and a black layer forms at the kernel base.
Dry-down
Dry-down is the rate at which maize kernels lose moisture in the field after physiological maturity.