Influence of tillage system on soft red winter wheat cultivar selection

Soft red winter wheat (Triticum apstivum L.) producers in the southeastern USA are adopting no-till production practices. Official wheat cultivar test ing programs, however, are conducted in conventional-till. The objective of this research was to determine whether soft red winter wheat cultivars per form differently across tillage systems, indicating the need for no-till cu ltivar testing programs. Twelve winter wheat cultivars commonly produced in the southeastern USA were tested in a split-plot design with tillage syste m as the main effect. The test was located in the North Carolina Piedmont a nd Coastal Plain in 1996 and 1997. In the Piedmont the soil type was Hiwass ee clay loam (fine, kaolinitic, thermic Typic Rhodudults), and in the Coast al Plain the soil was Goldsboro sandy loam (fine-loamy, siliceous, subactiv e, Aquic Paleudults). Plant density after emergence, head density at harves t, kernel weight, grain yield, and test-weight were determined and compared across cultivars and tillage systems. For each of these variables, environ ment and cultivar effects were significant (P less than or equal to 0.05). Tillage system had a significant effect only on plant density with average no-till stands being 8.3 % lower than those in the conventional-till system . Relative cultivar performance, or rank, did not change across tillage sys tems for any of these variables. Consequently, soft red winter wheat cultiv ars that perform well in conventional-till will probably be the best adapte d for no-till production. Separate cultivar trials are not required for the two tillage systems.