For the most part foliar diseases did not impact the Kern County wheat crop last year. The long range forecast from the National Weather Service predicts a 40 percent chance that rainfall will be below normal for the Southern San Joaquin Valley and a 33 percent chance that average air temperature will be below through April 2012 with May and June at average temperatures.
While the day weather pattern would lower the expectation of foliar disease incidences, cool temperatures have the potential to increase it. However, microclimates in and around wheat fields can be dramatically different. Varieties differ in their resistance to diseases that are common in California such as Stripe or Leaf Rust, Powdery Mildew, Barley Yellow Dwarf and Septoria tritici Blotch. They differ in their adaptability to the different climatic conditions and season length that occur in California. They also differ in maturity, straw strength and end use qualities. Disease resistance and other evaluations are performed annually as part of the University of California variety testing program.
University of California Cooperative Extension advisors and specialists conduct trials at 10 sites throughout the state to evaluate yield and other agronomic traits of commercially available varieties and advanced breeding lines. Forty-four common wheat and triticale varieties and 33 Durum wheat varieties were tested in 2011. Multi-year, multi-location tests provide the best information on yield stability and potential. The multiple environments also provide an excellent opportunity for rating other agronomic traits.
Relative yield, how one variety compares to another, may change from year to year. That is why it is critical to look at long-term data.
Choosing the right variety, or the misfortune of not selecting the right variety, has an impact on agronomic management decisions during the entire season. It can have even greater influence on crop marketing and potential profitability. The difference in yield from highest to lowest yielding variety in the Kern County test was 4,440 pounds per acre or more than $466 per acre difference in potential profit at today’s price. To a large degree, a variety’s genetic pedigree controls grain quality and yield potential. New varieties are introduced each year that have better qualities or higher yield. Other advanced lines, which may become varieties, offer higher yield potentials, improved disease resistance and good baking characteristics.
The 2011 California wheat crop was 749,000 acres including 108,000 acres of Durum wheat. Non-durum acreage increased by 67,000 acres, a 12 percent increase from 2010. Durum wheat acreage also increased 27 percent from 2010. It has averaged 108,400 acres for the past decade with the high and low at 65,000 acres and 176,000 acres in 2006 and 2009, respectively. Joaquin, PR 1404, Red Wing, Cal Rojo and Ultra were the leading red wheat cultivars by acreage. This represents a change in variety preference. Blanca Royale led white wheat acreage. Orita was the leading durum varieties. Plantinum was the most widely planted Durum wheat in the San Joaquin Valley representing 62 percent of the acreage.
There are some very good yielding varieties available. Four of the top 10 yielding common wheat varieties are commercially available. That also means that excellent varieties are in the developmental process and will be available in the next couple of years. While there are many varieties to choose from, care needs to be taken to select the best variety for one’s farming operation. Results from the Kern County wheat variety test and other pertinent varietal information can be obtained from the UC Cooperative Extension Office or on line at http://agric.ucdavis.edu/crops/cereals/cereal.htm .