Horticulture Student has Fruitful IDEA

Mark Brand, left, professor of plant science and landscaping, and Nathan Wojtyna '16 (CAHNR) look over grafted Aronia mitschurinii plants at the Floriculture Greenhouse on May 1, 2015. This project was funded by an IDEA grant. (Peter Morenus/UConn Photo)
Undergraduate Nathan Wojtyna is pursuing an IDEA grant project under the guidance of horticulture professor Mark Brand to make Aronia plants commercially viable by grafting the bushes at a height of 2 feet, so that all the fruit can harvested mechanically. (Peter Morenus/UConn Photo)


You may not have heard of it yet, but demand for Aronia berry, also known as chokeberry, is on the rise. Recent research shows the edible fruit and supposed “superfood” is extremely high in antioxidants and contains a myriad of health benefits. It’s also a native plant that grows well in North America and could command a high price for farmers. But there’s a problem.

Aronia mitschurinii grows on a bush, similar to blueberries, but the fruit gets so heavy that the branches droop low to the ground. Because of their size, mechanical harvesters that clear huge tracts of land miss everything below a 2-foot threshold – about a third of the fruit on an Aronia bush.

“That’s one-third of your profits sitting in the field, so that just makes it unrealistic [to grow Aronia berry commercially],” says Nathan Wojtyna ’16 (CAHNR).

Mark Brand, left, professor of plant science and landscaping, and Nathan Wojtyna '16 (CAHNR) look over grafted Aronia mitschurinii plants at the Floriculture Greenhouse on May 1, 2015. This project was funded by an IDEA grant. (Peter Morenus/UConn Photo)
Mark Brand, left, professor of plant science, and Nathan Wojtyna ’16 (CAHNR) inspect grafted Aronia mitschurinii plants at the Floriculture Greenhouse. (Peter Morenus/UConn Photo)

At the beginning of his junior year, when Wojtyna asked horticulture professor Mark Brand if there were any interesting research projects he could take on, Brand told him about the emails he had received from growers in the Midwest who wanted help figuring out how to make growing Aronia economically feasible.

Wojtyna, a horticulture and resource economics major, was awarded a UConn IDEA grant in fall 2014 to pursue the project.

The IDEA grants program is designed to provide undergraduates in any major a stipend of up to $4,000 to develop innovative, creative, and personally meaningful projects. While the ideas don’t have to be tied to a major or minor field of study, they do need to be guided by a student’s academic goals and plans for the future.

Wojtyna, who came to UConn planning to study pre-med before shifting gears and studying plants on a molecular and cellular level in plant science professor Gerald Berkowitz’s lab, eventually realized he wanted to perform practical research that could be applied to improving farming processes.

To solve the Aronia problem, Wojtyna and Brand decided to implement a concept found in nature called grafting, where the tissues of two plants essentially fuse together to create a new connected plant. One plant forms the rootstock, and the other the scion – the part that produces the shoots. The technique is used to create plants like weeping cherry trees, vineyard grapevines, and apple orchard trees.

Nathan Wojtyna '16 (CAHNR) grafts Aronia mitschurinii plants at the Floriculture Greenhouse on May 1, 2015. This project was funded by an IDEA grant. (Peter Morenus/UConn Photo)
Nathan Wojtyna ’16 (CAHNR) peels away the bark prior to grafting Aronia mitschurinii to another species of tree in order to control the height at which the fruit begins to grow. (Peter Morenus/UConn Photo)

“We literally graft them together – take one plant, peel the bark away. It’s kind of like when you heal a cut, and your body stitches it up,” says Wojtyna. “We do the same thing. Wound both of them, and then attach them together. Plants, if they’re close enough [species], have a cool thing where they actually knit together and function as a single plant.”

Aronia grows from the ground, with all the shoots and trunks meeting in one spot, so it can’t be pruned like a tree to ensure all fruit-bearing branches are above the threshold, according to Wojtyna. The rationale of the project is to graft the bush at a height of 2 feet, so that the researchers control where the fruit-producing plant starts to grow. That way, all of the fruit should be able to be collected by the harvesters.

Wojtyna and Brand chose to try grafting Aronia to five different species of trees: Sorbus aucuparia (mountain-ash), Sorbus alnifonia (alder-leafed whitebeam), Crataegus laevigata, Crataegus monogyna (two types of hawthorn), and Pyrus communis (Bartlett pear).

They suspected the Sorbus species would work best because Sorbus and Aronia can pollinate each other. “Genetically, they already work together,” Wojtyna says. A commercial plant that’s a combination of the two called Sorbaronia already exists.

The other trees were included in the study to determine whether there was a more cost-effective option, Wojtyna says.

In the initial phase of the experiment, Sorbus aucuparia was the most successful. Scions grew from 61 percent of those grafted at the 6-inch point, and 53 percent at 2 feet. The Sorbus alnifonia grafts failed 50 percent of the time, something Wojtyna attributes to seasonal timing and shipping problems rather than incompatibility.

“The results are promising, although the process will need to be perfected to a 90 percent success rate before we can recommend this to the industry,” he says. “But this seems very feasible, considering the information we now have from this experiment.”

The Crataegus and Pyrus trials were less successful, with scions growing in 15 percent and 20 percent of the attempts, respectively, and many failing to graft at all.

The shoots on the Sorbus aucuparia grafts grew an average of 45 centimeters in a single season.

Now, the plants that worked are growing in a pit-house, partially in the ground and covered by a roof to protect them from their first winter. Then they’ll be planted in a field, where Brand will continue to study their growth and potentially repeat the experiment – Wojtyna is set to graduate in May.

“We need to see how it actually grows in the field, because you can’t tell a grower, ‘Cut down your acres of blueberry and put this in’ without having watched it grow in the field for a couple years and making sure it still works,” Wojtyna says.

If the plants succeed, Wojtyna and other researchers predict Aronia berries could become as ubiquitous as cranberries have in recent years.

Brand is also working with a nutritional researcher. Like cranberries, the antioxidants make the berry tart and difficult to eat. But, says Wojtyna, “sugar will make Aronia berries go a long way, along with ‘nutraceuticals,’ and what we understand about the healthy components of food.”

Wojtyna, who plans to pursue his Ph.D. in tree-fruit production systems at Cornell University starting this fall, hopes to continue solving similar problems for farmers. He plans to one day work as a university researcher who consults for the farming industry.

He says he is grateful for how the IDEA grant process has helped him learn to run his own research project, something that is a rare experience for an undergraduate.

“It has been extremely helpful in allowing me to understand a) how to write a grant, and b) how to work with and shape and follow through on the grant,” Wojtyna says. Previously, he had worked in private research companies where the projects were already set up.

“But this one being exclusively free-floating, figure-it-out — it was a whole new ballgame,” he says, “which was really great.”