Development of Hard White Wheat

New hard white wheat varieties must be well adapted, high yielding, resistant to pests and adverse weather conditions, and produce quality grain. Researchers are working to combine all of these desirable characteristics into new varieties and that takes time. Established breeding programs for hard red winter wheat usually take 10 years or longer to develop a new variety. The program to develop improved varieties of hard white wheat took even longer, because it started without any experimental lines or related germplasm. The first experimental lines came from crosses between red wheat parents, which produced a proportion of white grain progeny when the parents have only one or two genes for red grain. These early lines generally were well adapted and high yielding, but the grain had low test weight and lacked all the quality traits that are associated with white wheat. Crosses with new germplasm and careful selection of the progeny eventually resulted in experimental lines that contained all the desirable traits.

The performance data on hard white wheat varieties (indicated by a (W) after the variety name), shows that they are highly adapted and their grain yields and test weights are similar to those of hard red winter wheat. Rain, high humidity, and low temperatures after ripening may cause the grain to sprout in the spike. Resistance to preharvest sprouting once was attributed to the pigment for grain color in red wheat; because white wheat lacks the pigment, it could not resist sprouting. This theory was disproved when several sources of genetic resistance to preharvest sprouting were discovered, and through wheat breeding programs this resistance may someday be incorporated into hard white wheat varieties. 

All production practices (seeding date, seeding rate, fertilization, and harvesting) are alike for hard white wheat and hard red winter wheat. The same equipment is used for both crops. However, extra attention is needed to avoid mixing the grain. A three to four year cropping interval may be need to completely control volunteer wheat when white wheat is to be planted after red wheat. Drills, harvesting equipment (combines, trucks, augers, grain-carts), and storage facilities must be cleaned carefully to assure mixture of the two classes does not occur. On-farm grain storage may be an indispensable aspect of white wheat production at its inception due to the fact elevators may not have sufficient demand to dedicate storage space for white wheat. Keeping grain of hard red winter wheat and hard white wheat separate is essential because of the substantially discounted prices paid for mixed grain. 

The potential problem of preharvest sprouting of hard white wheat also must be considered. The grain should be harvested promptly after it ripens to avoid exposure to wet, humid weather.