Drought + Heat Stress During Corn Pollination
RL (Bob) Nielsen, Purdue Agronomy
Drought stress combined with excessively hot air temperatures during the important pollination process can easily result in pollination failure or early kernel abortion in corn. Pollination may fail because of dessicated exposed silks, non-viable pollen, or asynchrony of silk emergence with pollen availability. Kernel abortion typically occurs prior to the kernel "milk" stage (R3) and most easily in the first week or so after successful pollination when photosynthetic output is not sufficient to meet the needs of the developing kernels. Failure of ovule fertilization by pollen results in "blank" cob tissue with no evidence of any kernel development at all. Abortion of newly fertilized ovules may occur so rapidly after fertilization that it appears that pollination failed. Abortion of kernel development in the week or two following pollination results in shriveled, white to yellow kernels scattered amongst surviving kernels.
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White, shriveled aborted kernels
Combination of "blank" cob tissue (failed pollination) and white, shriveled aborted kernels
"Blank" cob tissue (failed pollination)