Deep row cultivation after growth stage V8 may prune root systems severely enough to hinder row number determination. Applications of certain sulfonylurea herbicides beyond the labels' stated growth stage restrictions can decrease yield potential by interfering with final row number determination on the upper portion of the ear. Nearly complete defoliation by hail prior to growth stage V12 may photosynthetically 'shock' the plant and limit row number determination. The potential number of kernels per row is complete by about 1 week before silk emergence. This means that ear length will vary dramatically from year to year as growing conditions vary.
Severe stress can greatly reduce potential kernel number per row.
Conversely, excellent growing conditions can encourage unusually high potential kernel number. It is the policy of the Purdue Agronomy Department that all persons shall have equal opportunity and access to its programs and facilities without regard to race, color, sex, religion, national origin, age, or disability. Purdue University is an Affirmative Action employer. This material may be available in alternative formats.