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Glossary of Corn Terms


Tolerance to stalk cannibalization indicates a corn hybrid’s capacity not to exhaust its stalk reserves when it lacks nitrogen during a long season. Cannibalization empties the inside of stalks, resulting in greater vulnerability to lodging. 


Corn heat units.


Hybrids of similar maturity are compared according to their moisture loss during in-field drying. A rating of 1 indicates a slow drying rate, while 9 indicates a very rapid drying rate.

Ear Coverage:

A rating of 9 indicates that the husks are longer than the ears.

Grain Type:

  • VF = Very Flint
  • F = Flint
  • SF = Semi-flint
  • VD = Very Dent
  • D = Dent
  • SD = Semi-dent


Milk yield per acre based on 100% dry matter.


Net energy lactation.

Plant Height:

  • S = Short
  • MS = Medium/Short
  • M = Medium
  • MT = Medium/Tall
  • T = Tall
  • VT = Very Tall


  • 9 = Excellent
  • 5 = Average
  • 1 = Poor
  • R = Resistant
  • T = Tolerant
  • S = Susceptible
  • - = Not rated

Refuge %:

See below for information on Insect Resistance Management.

Relative Maturity:

In the absence of an industry-standardized maturity rating, relative maturity can be used to compare hybrids of similar maturity and moisture at harvest. An early-maturing variety will have a lower number while later-maturing varieties will have a higher number.


A higher number rating indicates greater root strength.

Spring Vigour:

Ratings are set during the 3 to 5 leaf stage.


The quality of a stalk refers to its resistance to lodging due to factors such as stalk rot. A higher rating indicates greater stalk quality.

Stress Tolerance:

A higher rating reflects the hybrid’s capacity to produce adequate yields under difficult conditions, such as
a colder season, compaction, or a field with a lower yield potential.

Test Weight:

A higher rating indicates a higher test weight.