“Just a bunch of briars, but some sophisticated ones at that,” John R. Clark likes to say about the blackberry varieties developed in the breeding program he directs for the University of Arkansas System’s Division of Agriculture.

But these briars have pedigrees and are in demand around the globe, which has led to partnerships between the Arkansas breeding program and companies in Chile and England, with more to come.

In 1997, Clark, a horticulture professor based on the university’s Fayetteville campus, inherited a unique collection of blackberry germplasm and continues to improve it in a fruit breeding program that also includes grapes, peaches, nectarines and blueberries. His predecessor, Distinguished Professor Emeritus James N. Moore, started the collection in 1964.

Moore started patenting UA varieties with the Reliance grape in the early 1980s and Clark has continued to do so. Royalties for the propagation of plants are paid to the university.

Clark says he realized that, while the germplasm collection exists to benefit Arkansas fruit growers, “we couldn’t keep it to ourselves if we wanted to.” Protecting a plant worldwide with plant breeders’ rights available in over 60 countries and strictly enforcing this protection is difficult, he says. Others can legally use patented varieties for breeding with no return to the university.

“Our testing of Arkansas breeding lines and varieties in other states and countries revealed opportunities to maximize genotype by environment interactions,” Clark says. “Some of our germplasm that doesn’t do well in the heat and humidity of our summer does great in a more moderate climate.”

Clark recognized that there were lines in the program — also in the grape, blueberry, peach and nectarine breeding programs — that likely would be discarded in Arkansas but might have use in other locations.

So, starting about 2002, Clark began broadened testing and breeding relationships with partners in various locations such as South America, Australia and South Africa in the southern hemisphere, where the growing season occurs during Arkansas’ winter, and the United Kingdom, where fresh fruit is not likely to be produced and marketed in competition with Arkansas producers.

The partnerships were developed to strengthen the program on behalf of Arkansas growers by generating royalty income for research.

One partner is Hortifrut, one of the world’s largest fruit growing and marketing companies based in Santiago, Chile. Another is Hargreaves Plants, a nursery company in Spalding, Lincolnshire, United Kingdom.

“Our partners pay for access to our material for use in the cooperative improvement programs, and if a variety is developed that is commercialized the university receives royalties,” Clark says.

Other partners are interested in simply growing already patented Arkansas varieties of blackberries, grapes, peaches, nectarines and blueberries. One of these is Eurafruit, which is testing Arkansas varieties on its farms in South Africa for production and shipment of fruit to Europe. Ozeki Nursery in Japan is licensed to propagate and market a variety of Arkansas blackberry plants.

“Blackberries are hot, right now,” Clark says, “and fortunately, for our purposes, it is mainly a fresh market crop with limited storage time compared to frozen berries.”

However, he adds, Arkansas growers could benefit from an expanded “market presence” over a longer period of time to strengthen consumer demand for blackberries if berries from other areas find there way into local stores.

Come June, Clark says, the deal-making goes on hold while he attends to his main chore of tasting berries and evaluating plants from this year’s almost 9 miles of seedlings at the Division of Agriculture’s Fruit Research Station on Red Lick Mountain near Clarksville. He’ll select plants for further crossbreeding and maybe one or two from advanced lines for consideration as new, patented varieties.

The Arkansas breeding program has produced some of the world’s most widely-planted blackberry varieties, including several that are thornless, and planting is on the increase in the U.S and other countries. Unlike the wild blackberry briars, the Arkansas varieties have erect canes rather than vines and are easier to manage. Named for Native American tribes, the most popular are Navaho and Ouachita.

The program achieved a major breakthrough in the late 1990s when the first “primocane fruiting” types were selected. Primocanes are first-year canes that normally don’t bear fruit. Blackberries normally are borne only on second-year canes. Thus, only about half of the canes on each plant produce berries. This new type of plant can provide options for growers in time of ripening and management of plantings.

Primocane-fruiting raspberries became commercially important about 25 years ago. They produce high-quality berries on plants that can be managed for production for longer periods, particularly into the fall season.

The Division of Agriculture has released two primocane varieties, “PrimeJim” and “PrimeJan,” named for James Moore and his wife. But they are not well-adapted to Arkansas conditions. Clark sees potential to license the primocane fruiting material to other breeding cooperators to help generate funding for research to combine primocane fruiting with other traits needed for Arkansas growing conditions.

“Science works best when scientists share information,” Clark says. Hybrid seedlings grown in Chile or England, for example, might generate a primocane fruiting plant that would be perfect for those locations or for Arkansas, he says.