Late-emerging corn seedlings
I was pursuing an explanation of why did some plants wilt and develop stalk rot when adjacent plants stayed green and complete grain fill on solid stalks. Were these plants individuals that were stressed for the whole season because they emerged late? Why these individual plants? In the early 70’s we had a cold wet spring in the corn hybrid observation plot, with uneven seedling emergence and an opportunity to tag those individual plants that adjacent to earlier emerging plants. Those individual plants were observed during the season. They were obviously less ‘vigorous’ than adjacent plants, had narrow stalks, and delayed ear shoots. I asked the seedstock manager to look at these tagged plants to see if they looked like inbreds, created by selfing in the hybrid seed production field. He replied that he had seen similar plants before and said it does make evaluation of hybrid purity in winter ‘grow outs’ difficult. Final notes at the end of that season showed that these late emerging plants had significantly fewer kernels, if any at all.
These plants did not develop stalk rot. Were they impurities in the seed lot, perhaps inbreds? The following year, hybrid seed was hand planted with extra space between plants. When these seedlings emerged, the same hybrid seed was planted between the seedlings. Those late planted seedlings were observed during the season. As suspected, Late-emerging hybrid plants performed as those in the previous year, having spindly stalks and few kernels but no stalk rot.
Those observations led this young observer of corn to look at other possible explanations for why stalk rot of corn and more experiments and eventual conclusion that the individual stalk rot plants had produced more grain yield than those individual plants environment could support, essentially depriving the roots of needed photosynthesis products to keep them alive.
Late emerging plants were detracting from yield and not the ones that develop stalk rot.
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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.