Purple Color in Corn Seedlings: A Valid Concern Affecting Yields?

The rainy season in combination with a long period of unusual low temperatures are causing slow plant growth for all summer crops, including corn. Cold temperatures and saturated soils are not only affecting corn stands through uneven emergence and lack of uniformity, but are also causing a phenomenon in young corn seedlings known as “purple corn.”

In many cases when the purple color is identified in small corn plants, the first thought that comes to mind is that this could be an indication of phosphorus deficiency. Phosphorus deficiency is also generally associated with stunted plants and thin stalks. Other potential causes of purple color can be hybrid-related, a buildup of sugars (sunny days/cold nights), and restricted root growth. Thus, the question becomes: What is the main factor affecting the plant color if the crop otherwise looks very healthy, uniform, and vigorous?

In recent years, purple coloring on corn seedlings has been documented in different environments under diverse management practices and hybrids. In many cases, the color is coming from the expression of genes for anthocyanin pigment formation. Multiple genes govern the expression of this color, and certain “cold sensitive” genes react to low temperatures (40-50 degrees F). Therefore, low nighttime temperatures such as those we have experienced at times over the past several days/weeks will promote purpling in corn seedlings. This condition is only expressed up until the six-leaf (V6) stage.

At this point, the purple color is simply the result of a small degree of cold temperature stress -- nothing severe. The plant is growing very slowly due to the cool weather (not related to the purple color), but good growth and development should resume after the temperatures go back to the normal for this time of year. As soon as the temperature warms up and plants grow rapidly, the purple color should disappear (after the six-leaf stage). If not, then consider taking a soil sample for potential phosphorous deficiency.

Will the yield be affected by this stress? Previous information collected by several researchers concluded that yield is not likely to be affected by this phenomenon. Producers do not need to worry about this phenomenon. Still, it is always good to continue scouting your acres for early identification of any potential problem affecting your crops.




Figure 1. Purple coloration in corn at diverse growth stages -- a result of the expression of genes for anthocyanin pigment formation. A close-up look with a microscope reveals that the pigment is only present on the top layer of the leaf tissues, without affecting the chlorophyll. The purpling effects varied with the leaf position in the canopy, with no clear pattern. Photos by Ignacio Ciampitti, K-State Research and Extension.


Latest News

How Important is U.S. Ag and Food to the Economy?

In celebration of National Ag Day and National Ag Week, the 2023 Feeding the Economy report shows just how vital the industry is to U.S. families, communities and the world.

Ferrie: Ready, Set, Whoops! A Fast Start To Fieldwork Could Cost You Big In Corn At V5

Caution can help you avoid creating compaction or density layers. Plus, if you're applying anhydrous now, allowing 14 days between the application and planting can prevent dead or damaged plants and costly yield dings.

Nebraska Farmland Values Jump 14% in 2023 — Up 30% in Two Years

This year marks the second-largest increase in the market value of agricultural land in Nebraska since 2014 and the highest non-inflation-adjusted statewide land value in the 45-year history of the survey. 

U.S. Milk Production and Cow Numbers Both Rise

The February 2023 USDA Milk Production report showed an 0.8% increase in year-over-year milk production with a total of 17.7 billion lbs. of milk. Also following suit, U.S. cow numbers also documented growth.

Crude Oil Prices Drop Below $70: What is the Outlook for Consumers at the Pump and Farmers Heading Into Spring Planting?

Oil prices are also off their highs of last year and gas and diesel prices are also sliding at the pump, but will that trend continue ahead of planting?   Energy experts are hoping the answer is yes.  

Can History Making $20 Billion in Inflation Reduction Act Get Rolled Out Quickly Enough?

Industry experts say the new legislative package represents a 'generational opportunity' for conservation funding and needs to reach U.S. farmers and livestock producers sooner rather than later, starting this spring.