Seed Size/Shape and Tillage System Effect on Corn Growth and Grain Yield

Abstract

This research was conducted to evaluate the effects of corn ( Zea mays L.) seed size/shape on field performance of commercially available corn hybrids under conventional tillage (CT) and no‐tillage (NT). Field studies were conducted in 1987 and 1988 under the two tillage systems with small‐round, small‐flat, large‐round, and large‐flat seed of hybrids LH74xLH51 and A632xLH39, on Piano silt loam (fine, mixed, mesic Typic Argiudoll) soil at Arlington and Janes‐ville, WI. At Arlington, there were also early (mid‐ to late‐April) and late (mid‐ to late‐May) planting dates. Under such stressful conditions as early planting, NT, and soil crusting during emergence, small‐round seed often was 5 to 15% lower in emergence than small‐flat and large‐round seed. Emergence rate, vegetative dry weight, silk date, grain yield (at similar stands accomplished by overplanting and thinning), and other growth parameters measured were not influenced consistently by seed size/shape. No‐tillage and early planting resulted in cold soil at planting, which delayed emergence, early growth, and silking and often reduced grain yield compared with CT, but tillage system by seed size/shape interactions were not important for these factors. These results indicate that corn producers should focus on genetic potential, seed quality, and seed price rather than specific seed sizes/shapes when selecting hybrids, except when planting under stressful conditions. With very early planting or NT, it may be advisable to avoid small‐round seed, or to increase seeding rate by 10 to 15% with this seed size/shape in order to obtain the desired stand.