Purdue News
Purdue News
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August 28, 2001 Pollination failure reduces corn yieldsWEST LAFAYETTE, Ind. – Due to pollination failure, some Indiana corn fields are showing serious tip fill problems and severely scattered kernel set, says a Purdue University Extension specialist. Bob Nielsen says pollination complications will cause corn plants in some fields to have ears with one to two inches of barren cob near the tip, which means yield loss. "For every absent ring of kernels around the cob, there is a yield loss of about five bushels," Nielsen says. "However, ear length potential this year was often exceptional because of favorable growing conditions prior to flowering, which may make up for the losses." Nielsen says the longer ear length led to tip silks emerging after pollen shed was finished. The number of developed kernels, between 30 to 35 per row, is still normal, even though one to two inches of ear tip are bare. Kernel abortion is caused by stressful climatic conditions, such as excessively warm nights during silking, severe moisture deficits or heavy cloud cover around pollination. All three conditions occurred this year in Hoosier counties during pollination. "The cause of abortion revolves around a limited photosynthate supply to the younger developing kernels," Nielsen says. "Such excessive shading or lack of intense sunlight soon after fertilization of the ovary occurs can easily abort kernels." Nielsen says not all tip fill problems are related to longer ears, warmer nights or limited sunlight. The biggest kernel set problems are mostly associated with severely clipped silks. Some ears of corn only have 15 to 20 harvestable kernels per row. In addition, there are varying degrees of scattered kernel set in the fields, he says. "It is unclear whether corn rootworm or Japanese beetles were the culprits," Nielsen says. "Goose-necked plants in many of these fields were a good indication that serious corn rootworm larvae feeding injury to roots was a problem earlier in the season." Kernel set problems seem to be in fields where uneven emergence or uneven seedling growth occurred, Nielsen says. "Normal and delayed plants side-by-side exhibit ears that are different as night and day in the success of pollination," he says. "Plants in fields with more uniform plant development exhibit less silk clipping in general and fewer problems with severe scattered kernel set." Nielsen says there are a number of reasons why uneven stand development occurred this year: … Uneven seedling emergence. … Injury from the Mother’s Day frost. … Uneven plant development brought about by the late May and early June cold snap. … Injury from post-emergence herbicide applications. … Chilling injury from the mid-June or early July cold snaps. … Injury from corn rootworm larvae feeding. Any of these stresses combined could have delayed plant development and silking, making them more attractive to corn rootworms or Japanese beetles than normal plants, he says. Weather related problems also could have caused pollination failure. During pollen shed, above normal temperatures could have sped up the process at the expense of later silk emergence, Nielsen says. He also said delayed silk emergence could have been caused by corn rootworm and Japanese beetle silk damage. Nielsen encourages producers to walk their fields and see if pollination problems are present. "I think it’s prudent for producers to determine if their field is suffering from pollination problems because it may impact their marketing strategies," Nielsen says. "If producers are planning on a 150-bushel crop and it is only 140 bushels, and they can tell that now, it may help them change their marketing strategy and producers won’t be surprised at harvest." Source: Bob Nielsen, (765) 494-4802, rnielsen@purdue.edu Writer: Jennifer Doup, (765) 494-6682, jdoup@aes.purdue.edu Ag Communications: (765) 494-2722; Beth Forbes, bforbes@aes.purdue.edu; https://www.agriculture.purdue.edu/AgComm/public/agnews/ Related Web sites: Poor Kernel Set Symptoms in Corn
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