Corn Reproductive Stage

Something went wrong. Please try again later...

By Dairyland Seed Agronomy Team

As silks and tassels have emerged and/or starting to emerge from corn plants and pollen is in the air, we have officially hit the reproductive phase of development in the corn plant. Depending on the relative maturity or day length of the hybrid, as well as weather/growing conditions, it can take 50 to 80 days from planting to tassel and silk emergence. As a general rule, early maturing products 90 day or less of relative maturity, take 50 to 65 days from planting to tassel and silk emergence. While a 100 day or greater relative maturity product may take 65 to 80 days from planting to tassel and silk emergence.

Growth Stage	Time Frame
Emergence to Tassel	50-80 days
Tassel To Black Layer	55-65 days

Once a corn plant tassels and silks have emerged, that corn plant is in the reproductive stage and its growth stage will be designated in “R” stages. From tassel and silk emergence until black layer, depending on hybrid day length and growing conditions, it can take 55 to 65 days.

Growth Stage	Reproductive Stage	Days After Silking
Tassel / Silking	R1	0
Blister	R2	10-14 days
Milk	R3	18-22 days
Dough	R4	24-28 days
Dent	R5	35-42 days
Black layer	R6	55-65 days

Once a corn plant has tasseled and silks have emerged, that corn plant is in R1 growth stage. Once a plant reaches the R1 growth stage, it has achieved its maximum overall height and has put on all the leaves it will put on. Any insects or disease that defoliate leaves are pulling from the photosynthetic surface area and reducing yield. Conversely, at this same time, the root system has reached its greatest width and depth in the soil profile. Much like corn leaves, any pest or malady that effects or burrows into the root system is reducing the available water and nutrients entering into the plant and, ultimately, yield.

The corn plant water usage peaks at the R1 (Tassel/Silking) to R2 (Blister) stage at roughly .3 inches of water per day (range .1 to .4 inches/day). Water use will vary with increasing or decreasing air temperature, solar radiation (sunny or cloudy days), humidity content and wind speed. The need for water lessens as the plant matures.

Nutrient uptake demand varies with Potassium (K) with the highest demand being at around R1 to R2 but Nitrogen (N) and Phosphorous (P) demand continues to R5. In almost all instances, if the plant experiences a deficiency of nutrients, it will pull from its leaf and stalk (storage) surfaces to fill the ear and kernels on the ear.

As always if you have questions regarding this or any other Agronomy topic contact your Dairyland Seed DSM or Agronomist.