2013 Wheat variety performance test results posted

All Oklahoma wheat variety test sites are now harvested and the results are posted at www.wheat.okstate.edu. I have posted a brief summary of the 2013 crop below. Over the next several weeks, I will be posting additional trial results on this blog along with opinion and analysis of results.



At the time of writing this report, 2013 Oklahoma wheat production is estimated to be approximately 114 million bushels, which is roughly 26% less than 2012 production (Table 1).  The production decrease was due to the combination of lower yields and fewer harvested acres. Given the challenges faced in the 2012-2013 wheat production year, however, most would consider the average yield and total production to be much better than expected.


Table 1. Oklahoma wheat production for 2012 and 2013 as estimated by OK NASS, June 2013



Harvested Acres

4.3 million

3.8 million

Yield (bu/ac)



Total bushels

154.8 million

114 million


We have had several dry starts for wheat planting in Oklahoma, but the fall of 2012 might go down as the driest of the dry. A few timely rains in late August and early September allowed early and mid-September sown wheat to emerge and get a rapid start on forage production. This was the last substantial rain that most of western Oklahoma received until early 2013. As a result, much of our October-sown crop remained partially emerged in dry soil until after the first of the year.


Wheat that had emerged in September had consumed available water by early November and turned brown by December. Many fields were assumed dead, as there was no green tissue remaining above the soil surface (e.g. Marshall Dual-Purpose trial). This left little to no grazing potential for many dual-purpose wheat producers. Our Stillwater forage trial, for example, had less than 500 lb/ac (estimated) of available forage in early December, which is our normal forage measurement timing.


Rain was not plentiful in early 2013, but there was enough to allow the wheat crop to rebound. Wheat seed that had been lying in the soil germinated and early-emerging fields that had turned brown from drought were resuscitated and brought back to life. Wheat in southwestern OK and the Panhandle remained on life support throughout the season, surviving but never really thriving. Given these extreme circumstances, the grain yield at our Chattanooga, Altus, and Hooker sites are nothing short of amazing. Although wheat finally emerged at our Alva, Balko, Buffalo, Cherokee, Gage, Keyes, and Lamont sites, the stands were far too variable for use in comparing the yield potential of wheat varieties.


Drought was not the only weather-related issue Oklahoma wheat producers dealt with in 2013. There were multiple rounds of freeze events in late March and early April. Wheat in southwest Oklahoma and the Panhandle was affected by different freeze events but both sustained 30 to 80% tiller loss and were largely written off in the weeks following the freezes. Outside of far southwestern OK, cooler than normal conditions and some replenishment of soil moisture allowed regeneration of tillers. This, along with extended grainfill duration, allowed many wheat fields to recover and produce greater than expected grain yields (e.g. Apache variety trial). The cooler than normal spring temperatures were beneficial for wheat grainfill, but also delayed harvest by about one month as compared to 2012 and about two weeks as compared to the long term average.


It was a fairly quiet year regarding foliar disease. Pockets of the state suffered from heavy powdery mildew infestation in March and April, and some wheat producers chose to split-apply fungicides to combat this disease. There were also areas affected by glume blotch, tan spot, and septoria, but there was not much leaf or stripe rust present.


Yellow and purple leaves were tell tale signs that a late spring flush of aphids had transmitted barley yellow dwarf virus to several Oklahoma wheat fields. Armyworms were present late in the season, but generally did not reach threshold levels prior to maturity and few fields were sprayed. Winter grain mites took advantage of slow-growing, drought-stressed wheat and were a frequently reported problem in southwest OK, but the wheat curl mite takes top billing among mite pests in 2013. The wheat curl mite transmits wheat streak mosaic and high plains viruses. These two diseases are fairly common in the Panhandle but do not typically affect wheat in central OK. In 2013 fields as far east as Kingfisher tested positive for wheat streak mosaic and several central OK fields were affected. Growers affected by wheat streak mosaic should take care to ensure that any volunteer wheat or corn is dead at least two weeks prior to planting to reduce the risk of this disease in 2013-2014.


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