As if the stresses that reduce photosynthesis isn’t enough to offset the balance of movement of sugars during grain fill, the 2019 USA Midwest had extreme water in the early season, even after corn was planted. Sugar movement, stimulated by hormones produced by meristem tips, goes to apical meristem of shoot prior to flowering and to root tips. After pollination the concentration of apical meristems in the ear redirects the flow towards the grain, competing with the flow towards the root tips.
If root growth was inhibited by extreme moisture in the soil, perhaps by low oxygen supply, does it result in fewer root tip meristems? If so, does this reduce its capacity to attract sugars during the season and does this increase the vulnerability to the root pathogens. This would result in increasing probability of the plant wilting during grain fill as well. Stalk rot follows after plants wilt.
Deterioration of stalk quality follows plant wilting during the grain fill period. Wilting is caused by root tissue unable to absorb enough water to be transported to leaves. Loss of water from leaves occurs through leaf stomata via evaporation. Dry, windy environment around leaves causes more rapid transpiration. Early season environment affects root growth and mid-season environment affects the size of grain sink. Genetics determine how the plant reacts to these environments. These multiple factors determine whether the grain successfully completes normal grain fill on plants with green stalks or not.
About Corn Journal
The purpose of this blog is to share perspectives of the biology of corn, its seed and diseases in a mix of technical and not so technical terms with all who are interested in this major crop. With more technical references to any of the topics easily available on the web with a search of key words, the blog will rarely cite references but will attempt to be accurate. Comments are welcome but will be screened before publishing. Comments and questions directed to the author by emails are encouraged.