One in 8000!

From ‘Sun-Diamond Grower’, written by Jamie K. Hartshorn

HGA newsletter, January 2004

That’s about how many hazelnut seedlings Oregon plant breeders must go through before one is worthy of release.

It pays to be patient if you’re a plant breeder. Take scientists at Oregon State University’s Agricultural Experiment Station for instance. Their quest for a new hazelnut variety for the kernel market took some 17 years from initial trials to final release. Many thousands of seedlings later, along came ‘Willamette’, introduced in 1990. “The new variety has shown both positive and negative points,” says Dr. Shawn Mehlenbacher, associate professor and plant breeder with OSU’s Hazelnut Breeding Program. The largest planting to date is a 40 acre block that went in last Spring, “but most growers are taking a wait and see attitude,” he says.

“Willamette’s biggest problem is that it doesn’t fall completely free of its husk at maturity, and because of that, nuts fall to the ground a week later than ‘Barcelona,’ the industry’s mainstay since its beginnings in the 1890’s.

While there have been no named introductions since ‘Willamette’, there are some promising numbered selections on trial in Corvallis. This spring there will be more than 40 in yield trials –all aimed at the kernel market. But because the oldest going through yield trials date back only to 1990, researchers won’t have the information needed to make a new release for several more years.

Each year the program plants 4000 new seedlings – 160 from each of 25 crosses, each genetically different. Throughout an eight year cycle, these thousands are winnowed to 3600, then to 2400, 1000, 100 and then 20. Of these, the best selections are used as parents in the next breeding cycle, and the evaluation process begins anew. Since the breeding program began in 1969, researchers have planted more than 60,000 seedlings (to 1995). 

When a seedling in a block does show promise, it is propagated employing a traditional and commonly used technique called tie-off layerage. The resulting trees are used according to these priorities:

  • Establish replicated yield trials.
  • Expose potted trees (13 of each) of the same selection to eastern filbert blight. The degree of susceptibility to EFB is determined by counting and measuring cankers 21 months later.
  • Establish observation blocks in grower orchards.

The OSU hazelnut-breeding program was launched in 1969. It’s actually two programs: one to breed for EFB resistance, the other to develop new varieties for the blanched kernel market. For the latter, breeders look for resistance to big bud mite; round nuts of medium size; high percentage of kernels; precocity and high yield; easily blanched kernels; few defects; early maturity; and free-falling nuts. 

Dr. Mehlenbacher concludes, “No matter what we do to speed up the process, it will still take 15 to 17 years from the time a cross is made until we have the information we need to justify releasing a new cultivar. We’re still trying to figure out the best way of simultaneously testing and increasing new selections.”