When Washington State University weed scientist Tim Miller teamed up with fruit researchers in the United Kingdom last summer, he was hoping to learn how weeds affect the quality and nutritional value of raspberries. He will travel to the James Hutton Institute in Invergowrie, Scotland for a second year of berry trials May 14-23 and, when he returns, his findings may help growers produce a higher quality "superfruit.”
Miller developed the series of trial projects in order to find out whether weeds, or the herbicides used to control them, produce fruit with less of the vitamin C and other antioxidants and nutrients that make berries so healthful and appealing to consumers. His research complements that of UK researchers who have perfected the method for measuring the amount of many compounds in raspberry and black currant, two of the so-called superfruits that contain large amounts of antioxidants.
Antioxidants are vitamins, minerals and other nutrients that protect and repair cells from damage caused by free radicals that can impair the body’s immune system. Superfruits are believed to help fight damage by boosting the immune system, enabling the body to better ward off colds, flu and other infections.
"Since we both grow berries, it was a natural thing for a Pacific Northwest weed scientist and the small fruit breeders in the United Kingdom to team up and see what some of the factors are that affect berry quality,” said Miller.
For raspberries, one common factor may be how weeds are managed.
"Producers in the Pacific Northwest, as in Scotland, use herbicides to manage cane growth and control weeds,” Miller said. Their research may determine - for the first time - whether weed control also influences berry quality, sugar content, color and antioxidant level.
According to Miller, last summer’s initial results linked the presence of some hard-to-control weeds like broadleaf dock, fireweed and quackgrass to such negative impacts on berries as lower sugar and vitamin C content and reduced color and juice sweetness. He said this year’s trials will provide even more useful information for berry growers and consumers across the globe.
"A better understanding of the potential effects of management decisions will give growers one more tool to improve not only the yield of their fruit, but also how good those fruits are for consumers,” Miller said.
"Whenever you test living plants in the real world, you can expect some variation in the results from year to year,” he said. "If berry quality factors respond the same way two years in a row, it’s a good indication that you are looking at a true response rather than simply a response due to temperature or some other environmental factor.”
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