Kansas is known for hard red winter and hard white winter wheat, and the wheat breeding programs at K-State are naturally focused on those predominant classes of wheat. But the university also has a small breeding effort in Manhattan focused on winter durum.
Durum is a white wheat used for pasta. Durum wheat is actually a different species than winter wheat or spring wheat. Durum is a tetraploid wheat, having 28 chromosomes, unlike hard red winter and hard red spring wheats, which are hexaploid and have 42 chromosomes each. Durum wheat generally has fewer tillers than hard red winter wheat, but larger head and larger seed.
The U.S. produces spring durum wheat. Most durum wheat is grown in the Northern Plains, primarily North Dakota with some acreage in Montana. There is also a small area of irrigated production in southern Arizona and California, and durum from this region is called “desert durum.”
Most varieties of spring durum are quite susceptible to Fusarium head blight (scab), and this is a significant concern for producers in the Northern Plains. Desert durum production depends on irrigation, and there are increasing demands from other users for water supplies in those areas. As a result, there is some interest in the potential for producing durum wheat in other areas, such as Kansas. There is interest from the processing industry in winter durum production in Kansas because of the proximity to mills, and because of some of the limitations on spring durum in the current areas of production. Also, the industry would like to diversify the sources of production beyond just the two current regions, to the extent that may be possible.
At K-State, researchers are looking at developing winter durum varieties rather than spring durum. There are a few other winter durum breeding programs in Austria, Romania, and at Virginia Tech University.
In producing durum wheat, achieving acceptable quality is critical. In particular, durum wheat needs to be at least 13 percent protein. It also must have acceptable yellow endosperm color. Although durum is a white wheat, its endosperm is a yellow or amber color and this is important in producing acceptable pasta.
Prices for durum wheat are typically higher than for hard red winter wheat – usually about $1 per bushel higher, although this fluctuates. Yields of the winter durum lines we’ve been testing have been lower than hard red winter varieties, however. We will have to get yield levels up before any commercial varieties are released.
Scab, winterhardiness, and head sprouting concerns are three concerns for winter durum varieties in Kansas. For these reasons, we foresee western Kansas south of I-70 as the primary potential area for production of winter durum. Durum generally has better drought tolerance than hard red winter wheat, but as a white wheat it is susceptible to head sprouting.
The winter durum lines currently in K-State's program have lower yields than it’d like (about 10% less than the best hard red winter varieties), and are later in maturity, but acceptable. The winterhardiness is probably okay now for Kansas, although there has not been a winter in Kansas that provides a good test for winterhardiness for several years. The protein level of the lines in our program is generally at or near 13 percent, as long as enough nitrogen is applied late in the season to promote protein. Getting the desirable yellow endosperm color has been a bit of a challenge so far.
K-State has 15 lines of winter durum in replicated tests at four locations in Kansas. In addition, there are 130 F3 generation lines, 300 F2 generation lines, and 400 lines in the doubled haploid program. K-State is anywhere from 5 to 12 years away from having a commercial variety of winter durum ready.
If winter durum is to be produced in western Kansas, it will have to be done as an identity-preserved program. Separate handling will be required since durum is a different class of wheat than hard red winter or hard white winter wheat. Researchers estimate there is enough potential market for up to about 250,000 acres of winter durum in Kansas as an IP wheat, if K-State can develop acceptable varieties.