Breeding Hops

 

The breeding objectives of the program are based upon production problems such as yield and pest resistance as well as brewing quality. Communication with brewery customers establishes the brewing quality objectives. Thus the objectives encompass alpha, aroma, and specialty hop breeding.

The hop breeding process can take over a decade. The first year of the program is the crossing year. The parents are selected based upon the objectives set at the beginning of the season. The following year, the seedlings from the crosses are established in a greenhouse and then planted into the seedling nursery where they are evaluated for one year. During this time the plants are screened for disease and sex. Eighty to ninety percent of the original population will be eliminated in the first year. The remaining females are transferred to the single hill (one plant) nursery. The single hill plants are evaluated for three years at which time selection is made. The selected plants are then expanded to multi-hill plots at a different (often multiple) location. After three years selection is again made. The selected genotypes are planted into elite commercial sized trials .2 - .4 ha. in size. Again the selections are evaluated for three years, at which time they may be released as a new variety.

Screening criteria during this process includes: yield, high alpha acid content, aroma, favorable oil content, downy mildew resistance, powdery mildew resistance, and good storage stability. The challenge is to combine the above traits, or different combinations of them, into one genotype.

In addition to classical breeding, development of polyploidy breeding, virus free propagation, and studies of hop genetics on the molecular level have begun. Genetic modification is not currently investigated in the program.