Crop breeding

Flavorful crops and their breeding challenges

When we think of food crops, we usually think of the basics. Wheat, corn, soy, potato and vegetable crops. These staple foods help sustain us for needed calories and nutrition. But, what about the challenges of food crops that add a little extra flavor to our diet? Today we explore the challenges in breeding hazelnut, hops and mint!


Most of us don’t eat hazelnuts by the handful – but that could change one day! On their own, hazelnuts are delicious, and their fatty acid profile is identical to olive oil. Healthy snacks, here we come!

Hazelnut husks next to the brown-colored nuts. A metric ruler shows the unshelled-nuts are about 1.5 cm in diameter.
Variety “PollyO” hazelnut developed at Oregon State University. This new variety combines taste, yield, maturity and many good qualities. Credit: Rebecca McCluskey.

But, only a small portion of the world’s hazelnuts is sold in-shell during the Thanksgiving-Christmas holiday season – seven percent. The remaining 93% is cracked and the kernels used in chocolate-hazelnut spreads and an array of chocolate productions and baked goods. Demand for kernels exceeds supply.

Three greyish branches showing dark grey spots of blight disease.
Eastern Filbert blight shown on the branch of an infected hazelnut tree. Credit: Rebecca McCluskey.

Oregon State University’s hazelnut breeding project is developing new cultivars resistant to eastern filbert blight. This disease is caused by the fungus Anisogramma anomala accidentally introduced from the eastern United States. We are also looking for new cultivars that can resist insect pests, like filbertworm, brown marmorated stink bug, and Pacific flatheaded borer.

The future looks very bright. Orchard management is mechanized, so few people are needed. The Willamette Valley is well-suited to hazelnut production. Acreage devoted to growing hazelnuts in Oregon has expanded from 29,000 to 65,000 in the past decade. By creating hybrids between the European and American species, we hope to expand the areas suitable for hazelnut production.


Craft brewing fans are also fans of hops – the crop that gives bitterness, flavor and aroma to beer. (Read about challenges in breeding companion crops like barley and wheat.) You might not know that hops are also used as a preservative. They can be used as an ornamental plant for landscaping, and have potential for use in human health and livestock production.

Green vine-like hop plants growing upright.
An experimental hop genotype at flowering in an advanced testing nursery. Credit: Shaun Townsend.

Hop is the only known plant species that produces lupulin. This is a complex mixture of many hundreds of chemical compounds. Further studies are needed to determine if lupulin, or its components, could have a medicinal benefit.

Hop faces similar challenges that other crops face; disease and pest issues, lack of water, and other similar production problems.

On the fun side of breeding challenges, breeders are working to develop new types of aroma hops – the types that add rich flavors to beers. These types of hops are dominating the market, and breeders are looking for new sources of flavor and aroma.

Hop breeders are identifying and incorporating new disease and pest resistant genes into hop, and with aroma hops dominating the market, new sources of flavor and aroma are being sought. Beer is an important beverage for many cultures, and hops will continue to be in demand as one of the key ingredients in beer production.


Ah, fresh breath. Many of us can thank the mint oil in our toothpaste for that. Did you know that mint oil is actually secreted by the mint leaves? Mint oil is produced in special leaf hairs on the lower surface of mint leaves. Under a microscope, they look like shiny bubbles of awesomeness!

A microscopic view underneath mint leaves showing bubbles of mint oil.
The leaves of mint secrete the flavorful oil we use in foods, toothpaste and other common items. Shown: mint glandular trichomes. Credit: Kelly Vining.

Distilled mint oil is used not only in toothpaste, but in a wide variety of consumer products, candies and medicines. The fungal disease Verticillium wilt has been the biggest challenge to mint production in the Pacific Northwest for decades.

Today’s mint has been cultivated – for flavor, yield and many other attributes. Today, breeders are looking to mint’s wild relatives for help in breeding types of mint that are still flavorful, but that are resistant to Verticillium. The wild relatives of cultivated mint may have genes responsible for conferring the wilt resistance trait. Introducing a new cultivar with fungal resistance will help create a more sustainable mint industry.

By Shawn Mehlenbacher (hazelnuts), Shaun Townsend (hops), Kelly Vining (mint), Oregon State University

About us: This blog is sponsored and written by members of the American Society of Agronomy and Crop Science Society of America. Our members are researchers and trained, certified, professionals in the areas of growing our world’s food supply while protecting our environment. We work at universities, government research facilities, and private businesses across the United States and the world.

Categories: Crop breeding

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