Variation in Maize Hybrid Germplasm Performance following a Winter Rye Cover Crop

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Witt, Mike
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Cover crop introgression into conventional corn and soybean rotational systems is a practice employed by some farmers in today’s upper Midwest farming landscape. The most utilized cover crop species in the state of Iowa has been winter cereals, specifically winter rye (Secale cereale L.) (Miguez, 2016). However, the two main factors hindering a greater adoption of rye cover cropping systems are the reported yield reductions in corn produced following a winter rye cover crop (Acharya et al., 2017) and time constraints for spring planting of corn (Johnson, 1998). Both of these factors can add significant investments to farmers that require system assessments to ensure a winter rye cover crop is a justifiable change to their cropping operations. The current recommendations of waiting seven to ten days, or longer, after winter rye cover crop termination before planting a corn crop (Raimbault, 1991) has been shown to reduce the chance of having a significant decrease on corn yields (Raimbault, 1991). However, this seven to ten waiting period can be problematic for farmers as it reduces the flexibility farmers require to increase profitability and corn yields. Maize is a very diverse crop that has over 300 races and has been adapted to climates all over the world (Troyer, 1999). This ability to adapt, and multiple cultivars, makes it very possible that certain varieties may have the ability to tolerate the factors that can cause yield loss from a winter rye cover crop. The objectives of this study were to determine if genetics from a diverse maize portfolio could show tolerance, expressed as lack of yield reduction, when planting corn followed by an immediate glyphosate termination of a winter rye cover crop and what physical characteristics changed within the hybrids or grain as a result.

Cover Crop, Winter Rye, Genetics, Grain Quality, Corn, Germplasm