In north Alabama, yield losses of 21 percent, 12 percent and 21 percent were observed for the 2010, 2011 and 2012 seasons, respectively.

In south Alabama, yield losses for the same years were 16 percent, 20 percent and 55 percent.

In central Alabama, no yield differences were observed in 2012; however, yield losses between 26 percent and 28 percent were observed in 2010 and 2011.

The data also showed that planting 15 days earlier than the producers’ planting date resulted in yield increases in 2010 and 2011 across all locations, though no benefits to this earlier planting date were observed in 2012.

The effect of planting date on yield was also studied using data from 14 years of trials in Tifton, Ga. Data showed yield declines in varieties that develop heads late in the season. Yield losses were higher for later planting dates than for the standard planting date.

Research results confirm that choosing the right variety and planting it at the right time can positively affect wheat development and final yield, says Ortiz. This means choosing varieties and planting dates best suited to your specific growing season and location.

The following are important points to consider:

• The differences among varieties are most expressed at heading date and least expressed at maturity when the grain moisture is almost the same.

• In selecting varieties and planting dates, be aware of freeze damage and vernalization.

• Producers in the southernmost areas might choose early plantings for short vernalization varieties. This carries some risk because early plantings increase the likelihood of early growth which, in turn, may result in severe winter kill or damage from late-spring freezes.

• Early maturing varieties are good options for planting late in the season. In cases where you don’t have information about a variety’s vernalization, remember that, as a general rule, it requires little to vernalize.

• Take special care with delayed plantings of early maturity varieties in the southernmost areas. In cases where planting is delayed a month with respect to the standard planting date, yield losses tend to run higher than they run in northern areas.

• Later maturing varieties, which are more likely to avoid freeze damage, are generally better suited to the northernmost regions. Data collected in Belle Mina, Ala., between 2010 and 2012 show that early plantings for medium and late-maturity varieties resulted in higher yields compared to the early maturity variety. Yield losses and low test weight might be expected if choosing late-maturing varieties for late plantings because of lack of proper vernalization or late grain-filling occurring in hotter weather.

• A delayed planting date may result in reduced yield, reflected in reduced seed weight, though these effects vary between varieties and locations.

phollis@farmpress.com