The full report for this year’s variety performance tests is now available on the wheat.okstate.edu website. You can also access it by clicking here.
I want to thank the Small Grains Extension crew, our Oklahoma State University Extension personnel, our farmer cooperators, and the participating seed companies for another successful year for the variety testing program! I also want to thank the Oklahoma Wheat Commission and Oklahoma Wheat Research Foundation for their financial support!
At the time of writing this report, 2017 Oklahoma wheat production is estimated to be approximately 89.1 million bushels, which is about 35% less than the 2016 production (Table 1) and 9% less than the 2015 production. The lower total grain production is the result of less wheat acres in the state this year. The 4.5 million planted acres was down 10% compared to the previous year, and with low wheat prices during the season, harvested acres were down as well. Number of harvested acres is estimated at 2.7 million, which is 23% less than in 2016 (Table 1). Despite the lower harvested acres, the statewide average yield is projected at 33 bu/ac. This is 6 bu/ac (18%) less than the record-tying 2016 state average but 4 bu/ac (12%) greater than the previous ten-year average.
The 2016-2017 wheat growing season can be characterized overall by periods of rainfall and near optimal growing conditions at critical times. The growing season got an early start with rainfall in late August, prompting producers interested in targeting fall forage to begin planting. Planting continued to move rapidly during early September, and most of the wheat at this time was sown into adequate soil moisture and emerged rapidly. Wheat intended for grain-only was sown during the average timeframe of early- to mid-October. A majority of the wheat sown at this time also had adequate soil moisture for good establishment, but most of the Northwest and Panhandle regions of the state were not as fortunate. Dry soil conditions in those regions resulted in suboptimal stands or no germination at all. After mid-October, little precipitation fell throughout the state for the remainder of the fall, and temperatures were above normal. Crop conditions during the early part of the growing season were rated mostly good, but with the lack of rainfall during the latter part of fall, crop conditions began deteriorating by the end of November. Fortunately, most of the wheat that was sown into adequate soil moisture was able to establish adequate above- and below-ground growth before going into winter dormancy.
Warmer than normal temperatures continued throughout much of the winter. January and February are normally very dry months for the southern Great Plains. Fortunately, much of the state received two to four inches of precipitation during mid-January. While some of the precipitation came in the form of ice in the Woodward area, it did not do much damage to the crop. It also provided the soil moisture needed for some wheat to germinate in the Northwest and Panhandle regions that had been sown in dry conditions.
With the above-average temperatures during the winter, plants broke winter dormancy ahead of normal, and spring green-up advanced quickly. The first hollow stem growth stage was reached for many varieties before the end of February, almost two weeks ahead of normal. Another round of widespread showers fell across much of the Wheat Belt on February 20, excluding the Panhandle and northeastern parts of the state. For some areas, this provided a boost to help plants recover from grazing injury. Other areas, especially south central Oklahoma, did not receive as much of this needed rainfall, and as a result, some grazed wheat pastures did not recover as well. Considering the warm temperatures during spring green-up, the prevailing thought was that much of the wheat would be mature and harvested by mid-May. However, temperatures returned to normal and slightly below normal during mid- to late-March. Many areas received another round of rainfall at the end of March, providing adequate soil moisture as the wheat crop transitioned into reproductive growth. Cool temperatures and adequate soil moisture persisted throughout heading and grain fill, favoring kernel filling. One abnormal weather event that occurred this year was a foot of snow that accumulated in the Panhandle on the last weekend in April. This did result in lodged plants and some lower test weight values, but the overall effect on yield was not as detrimental as expected at the time.
Most wheat was mature in southwestern Oklahoma by the middle of May and by the end of May in the central part of the state. Producers for the most part were not delayed by rainfall events, and with the dry weather during June, much of the wheat was harvested timely and quickly. Overall, harvest was almost complete in the state by late June.
Yields throughout Oklahoma were variable depending on location but were above average overall. Part of this variability was due to overgrazing and whether an area caught or missed a rainfall event that occurred only about every three to four weeks throughout the beginning of 2017. Field averages of 30 to 40 bu/ac were the norm across much of the state, but higher averages, even into the 60 to 70 bu/ac range, were not uncommon in some areas. Test weights throughout harvest remained at or above 60 lb/bu for early-harvested fields and did not drop much below the upper 50’s towards the end of harvest.
Different insect pressures were a concern at times during the growing season, but few were widespread, overlapped, or season-long. Some of the wheat planted in late August into early September was hit hard by fall armyworm, and some fields had to be replanted. Dead tillers on varieties susceptible to Hessian fly showed up on early planted wheat in areas of southwest Oklahoma during mid-fall, but only a couple reports of Hessian fly were documented during the spring. The dry weather in northwest Oklahoma through the winter provided ideal conditions for winter grain mite and brown wheat mite to thrive on wheat plants coming out of winter dormancy. Aphids were not really on the radar screen of most producers until mid-March, but this turned out as not as big of a problem as has been observed in other previous years. Despite the low aphid numbers, it was not hard to find Barley Yellow Dwarf (BYD) as flag leaves and heads started to emerge. While there was quite a bit of purpling and yellowing associated with BYD, there was not as much stunting as sometimes observed with early-season transmission of the virus. Wheat Streak Mosaic (WSM), transmitted by the wheat curl mite, was a significant issue for producers around the state, but the majority of the affected areas seemed to be concentrated in areas of southwestern and northwestern Oklahoma, as well as the Panhandle region. Yield reductions were definitely apparent in fields infected with WSM.
The warm temperatures and available moisture during the fall prompted the development of some foliar diseases, primarily leaf rust. Leaf rust spores were able to survive the winter due to mild conditions, but the disease was slowed by hot temperatures and lack of available moisture during spring green-up. However, when temperatures returned to normal during mid- to late-March, the abundant inoculum present allowed leaf rust to become one of the top diseases for producers across most of the state. The presence of leaf rust during 2017 was abnormal compared to previous years as it developed sooner and persisted through grain fill while also reaching a wider geographic area. In addition to leaf rust, stripe rust was present, but at low to moderate levels in isolated areas and not as widespread throughout the state as it was in 2015 and 2016. Because of the impact that both rusts have had over the past couple years, producers were more open to apply a foliar fungicide to susceptible varieties, with many fields throughout the state receiving at least one fungicide application. Variety trial results from Apache, Chickasha, and Lahoma indicated again this year that producers were well justified in spraying many of these acres. Grain yield of the variety Bentley, for example, resulted in a 27 bu/ac increase at Lahoma when treated once with a foliar fungicide at flag leaf emergence. Our results at Lahoma also showed the power of genetic resistance to disease in varieties such as Doublestop CL Plus in which the fungicide treated plots only resulted in a 1 bu/ac increase in yield over the non-treated plots.