A New Look at an Old Nut

Together with one of his students, Thomas Molnar, Funk brought many types of nut-producing trees to Rutgers—including walnuts, chestnuts, almonds, hazelnuts and pistachios—to test their viability as farm crops. His goal was to develop a breeding program focused around the two or three nut species that did best here. From that program would come new cultivars and, with them, a new industry. Hazelnuts stood out as having great potential. Molnar, now assistant professor of plant biology at Rutgers and a plant breeder at the Rutgers New Jersey Agricultural Experiment Station, focused his research on developing hazelnut trees that can thrive in New Jersey.

The American hazelnut, native to much of the eastern United States, produces nuts that are small and protected by a thick shell. This makes them unsuitable for commercial production. Hazelnut production in this country, which is limited to a small area in the Pacific Northwest, is based on a few European cultivars that have been selected to produce meaty nuts with thin shells. But unlike our native hazelnuts, European cultivars are susceptible to eastern filbert blight, a fungal disease that can kill hazelnut trees within a few years of planting. The goal of the Rutgers breeding program is to develop hazelnut trees that are resistant to blight and consistently produce a high volume of high-quality nuts.

“Through breeding, I can take this Italian tree, which has excellent nuts, cross it, grow out the offspring and find one that’s got good nuts and is resistant,” explains Molnar. “That’s what we have been doing here for the past 12 years or so—crossing the good ones with the resistant ones and looking for a combination of the two.”

The first step in the breeding program was to gather a broad array of diverse genetic material from cultivated and wild hazelnuts in hopes of finding those rare plants that are blight resistant. Funk and Molnar planted European cultivars, American-European hybrids and hybrids of Turkish tree hazels. And they planted hazelnuts, which are the seeds of the hazelnut tree. For ten years running, Funk sent Molnar on nut-collecting trips that included areas of Russia, the Ukraine, Belarus, Moldova and the Baltic countries. There Molnar collected nuts from the wild and from other research institutions. He also purchased hazelnuts from roadside stands, bazaars and small markets.

Collecting nuts is the easiest way to capture a wide spectrum of genetics. The nuts Molnar purchased in those markets and bazaars were often harvested from backyard trees. Such trees likely developed over generations from localized selection—offering the Rutgers team genetic material that differed from the common commercial cultivars. And, because hazelnuts are wind pollinated, the pollen that fertilizes fl owers even on cultivated trees can come from anywhere—including the wild hazelnuts that still thrive on the hillsides in these regions. This mixing of wild and domesticated trees increases the genetic diversity in the resulting nuts.

Thousands of hazelnut trees have been planted at Rutgers and intentionally exposed to blight, their ranks then thinned to include only those that survive the exposure. Years of crossing the surviving trees has yielded many sources of resistance, so that blight is no longer the biggest obstacle to developing hazelnuts for New Jersey. Molnar’s focus now is on improving the yield and quality of nuts. “The betterquality nut I can develop for our trees, the better price future farmers will get for them,” he says.

To guide his assessment of hazelnuts in the lab, Molnar uses quality standards from Ferrero, the world’s largest purchaser of hazelnuts and maker of Nutella and Ferrero Rocher chocolates. Companies like Ferrero pay a premium for quality, especially if it approaches the quality of the Tonda Gentile delle Langhe—a premium hazelnut grown in northern Italy that is prized for its superior fl avor, bright white color and roundness, and the ease with which the nuts shed their skin after roasting.

Given a growing demand for hazelnuts and a shortage of highquality hazelnuts in the world market, Molnar believes that our farmers will benefi t greatly if New Jersey becomes a center of hazelnut production. Still, he is cautious about moving too quickly to get his experimental varieties onto farms. Hazelnut orchards can be productive for 60 years, so it is crucial to have trees that will perform well over time. Molnar predicts that within fi ve years he will be ready with plants, but even then, he wants farmers to start slowly by planting only one or two acres.

Once the quality and yield are established, Molnar knows that hazelnuts will appeal to New Jersey’s sustainably focused farms (see sidebar). Compared to most annual crops, their water needs are small and they require little in the way of inputs such as fertilizers. Hazelnuts grow well on slopes not suitable for cultivation, providing income from previously unused or misused land. As a perennial, hazelnuts don’t require annual plowing, and they don’t need particularly rich soil. They develop an extensive root system that can stabilize soil to prevent erosion, capture rainwater to recharge groundwater and prevent fl ooding, and sequester carbon, which may help to slow climate change. And they create windbreaks and habitat for wildlife.

New Jersey’s small size and dense population require that we make good use of our land, both economically and ecologically. To that end, Molnar shares J. Russell Smith’s vision of benefi ting humanity and the environment by integrating more nut crops into our farms and landscapes. “What really inspired me when I fi rst started working with Dr. Funk,” says Molnar, “was the idea that, when you look across a suburban landscape, you see all of these trees that could be nutproducing trees, like improved hickories or pecans, that have good nuts, provide shade, and have other ecological properties.” The widespread planting of improved hazelnuts will be a signifi cant—and tasty—step toward realizing that dream.