SEED QUALITY EFFECT ON CORN PERFORMANCE UNDER CONVENTIONAL AND NO-TILLAGE SYSTEMS

In northern regions, no-tillage corn (Zea mays L.) planting often results in reduced and/or delayed seedling emergence and growth. The objective of this research was to evaluate the effects of seed quality on the performance of three commercially available corn hybrids grown with conventional-tillage (CT), no-tillage (NT), and no-tillage with in-row residue removed (NT-R). Field studies were conducted under the three tillage systems with seed lots having high (95-99%), medium (89-98%), and low (84-95%) warm and cold germination test values. Hybrids used were FR20A X FR31, LH74 X LH51, and A632 X LH39. The studies were conducted from 1986 to 1988 on Plano silt loam (fine, mixed, mesic Typic Arguidoll) soils near Arlington and Janesville, WI. There were also early (mid- to tate April) and late (mid- to late May) planting dates at Arlington. Increased residue cover with NT and NT-R systems resulted in 2 to 4-degrees-F cooler soil temperatures at planting compared to CT, which reduced average percentage corn emergence by 3%, delayed emergence by 2 to 5 d, reduced vegetative dry weight at 45 d after planting by 30 to 60%, delayed silking 5 to 7 d, and increased harvest grain moisture 1 to 5%. Average grain yields were also reduced by 9% under NT compared to CT. Compared to high quality seed, medium and/or low seed quality caused 4 to 6% lower emergence, delayed emergence less than 1 d, reduced vegetative dry weight by 10 to 15%, extended days to silking by 1 to 2 d, increased grain moisture about 1%, and decreased average grain yield by 4% (despite thinning to constant final stands). Seed quality effects were usually smaller than tillage system effects, and tillage system by seed quality interactions were infrequent. Special concern about seed quality under NT is unwarranted, but to optimize probability for high yields growers should plant high quality seed regardless of the tillage system used.