High-throughput Technologies Get Fruit Breeders’ Juices Flowing
Scientists in Washington State University’s horticultural genomics program are the first to routinely provide DNA information to their colleagues in tree fruit breeding programs to assist with the development of new apple varieties. The genes associated with desirable traits have traditionally been comparable to needles in a haystack, but marker-assisted breeding techniques make the search a lot more manageable.
The process begins when leaf samples are plucked from greenhouse seedlings, placed in individual clear tubes half-filled with small silica beads, and delivered to lab technician Terry Rowland. Using state-of-the-art technology, Rowland looks for indicators within the DNA that predict the cultivar’s flavor, texture, size, disease resistance, health-benefiting properties, or other profit-bearing characteristics. To speed up the procedure, he uses high-throughput machines to test extracted DNA from about 800 leaf samples at a time.
He then runs the DNA tests on about 2,000 samples a day and delivers the results to breeding programs. Last year, Rowland conducted an estimated 8,000 DNA tests during a three-month period.
With apple and cherry season quickly approaching, Rowland will soon be a busy man again. “Sweet cherry and apple seedlings have already germinated and are eagerly offering up their first leaves,” program leader and assistant professor of horticulture Cameron Peace said.
Pinpointing specific traits before the fruit trees mature results in substantial financial savings. The service allowed researchers to more efficiently use $87,000 for the apple and cherry breeding programs in 2010 alone. Rowland said that an unexpected discovery was some seedlings that have three sets of chromosomes instead of two–just one example of the type of marker-indicated information that breeding programs can use. Kate Evans, director of the WSU apple breeding program, said the extra set of chromosomes usually results in a larger tree with bigger fruit and leaves.
Once a new cultivar is developed, growers need to be convinced it is worth adopting. Genetic information can be used to help describe which other cultivars can be compatibly planted to ensure a good fruit set, as well as the potential to produce high quality fruit and be self-fruitful (capable of setting a crop of self-pollinated fruit).
“The idea is that if growers know which new cultivars are genetically superior, they are more likely to produce the fruit commercially,” Peace said.
The breeding programs use the genetic information to determine what qualities to keep in their apples or which to pair with another trait for better taste, texture, or storability. Rowland said this information ultimately enables consumers to choose from consistently high quality fruits. “When you pick up two pieces of fruit that are of the same variety you are going to know that both are of the same high quality,” he said.
Peace and Rowland will continue focusing on identifying and applying the markers that indicate sweetness and fruit quality retention after storage. “To know that I’m a part of something bigger than just what we do here [in the lab] makes it that much sweeter,” Rowland said.
By Rachel Webber, WSU CAHNRS MNEC intern
Learn more about WSU’s interdisciplinary research efforts to breed new fruit varieties by visiting http://bit.ly/efQFhR.
A Tree Grows in D.C., Thanks to WSU Expertise
Fourteen hundred years ago, or so the story goes, the emperor of Japan planted a cherry tree in the village of Neo. That tree still stands, now at over 50 feet tall and 30 feet in diameter. The ancient usuzumi (“light gray”) flowering cherry tree has survived earthquakes, typhoons, and an ant invasion. A little more than a decade ago, the people of Neo decided to share their tree’s beauty deserved a wider audience, so they presented the United States with cuttings.
Those cuttings were propagated to create many of the flowering cherry trees that today line the National Mall in Washington, DC.
Before the Neo cherry cuttings took root in the US Capital grounds, they were sent to WSU’s Irrigated Agriculture Research and Extension Center in Prosser. Bill Howell was the operations manager for IR-2, a predecessor of the National Clean Plant Network for Fruit Trees. “When it came to us, the cuttings were in pretty bad shape,” Howell said. “The budwood sticks were dry and shriveled. But somehow we got them to grow.”
Tests indicated that the trees were infected with at least two viruses. “We had to clean the viruses out of the trees before we could release them to be propagated,” said Howell. That meant putting the trees through heat therapy. It took another three years for the trees to get a clean bill of health. Eventually the trees were planted along the Potomac River near the Roosevelt Memorial.
On a recent visit to Washington D.C., Howell took some time to visit the trees. “My kids like to call them ‘Dad’s trees,’” he said. “But it’s the kind of research and science our people do every day at the NCPN-FT and they should get the credit.”
Those people include Jan Burgess, who conducts heat therapy on plants; James Susaimuthu, who analyzes plants undergoing virus indexing; Elmer Wilcowski, who bud grafts the trees needed for indexing; and Shannon Santoy, who runs molecular diagnostics for plant diseases.
The whole crew works together to make sure growers can get fruit trees without viruses. And occasionally, they see to it that our nation’s capitol is graced with healthy flowering cherry trees.
“We’ve cleaned viruses out of a lot of new fruit tree varieties planted in orchards all over the world,” Howell said. “But the usuzumi flowering cherry — that really shows what we can do for flowering trees.”
By Terri Reddout, WSU IAREC
Learn more about the National Clean Plant Network by visiting http://bit.ly/gkO1Rt.
$1 Million Grant Funds WSU Extension “Healthy Gardens, Healthy Youth” Project
WSU Extension is the lead institution on a new “Healthy Gardens, Healthy Youth” project funded by a $1 million grant from the USDA Food and Nutrition Service. The grant was announced today by Agriculture Secretary Tom Vilsack. Aimed at reducing childhood obesity and improving nutrition, the pilot project spans four states, will serve an estimated 2,800 students at 70 elementary schools, and will engage low-income students in the physical activity involved in growing food and learning life skills. The Cooperative Extension Services of Iowa State University, Cornell University, and the University of Arkansas are collaborating with WSU Extension on the project.
“School gardens hold great promise for educating our kids about food production and nutrition,” said Vilsack. “Learning where food comes from and what fresh food tastes like, and the pride of growing and serving your own fruits and vegetables, are life-changing experiences. Engaging kids in our efforts to end childhood hunger and curb childhood obesity is critical if we are going to succeed.”
“Across the nation, communities are facing the interrelated problems of obesity and chronic diseases associated with poor nutrition and lack of physical activity, which are often linked to poverty, food insecurity, lack of access to or utilization of open or green spaces, and limited understanding of the role of nutrition and physical activity play in overall health,” said Brad Gaolach, the project’s lead scientist and director of Pierce and King County Extension.
The project will utilize WSU Extension educators’ expertise in 4-H, gardening, and nutrition programs. Additionally, Extension researchers in all four states will assess both the process of implementing gardens in low-income schools and the nutritional outcomes of the project. King County is a nationally recognized nexus of efforts to improve local nutrition and confront health problems through gardening and other outdoor activities.
“We’ve been working in this arena for at least 10 years,” said Gaolach. “To me, the exciting thing is that this grant validates the value of the land-grant university system. We are, I think, the only organization that has programs in gardening, youth development, and nutrition; is capable of disseminating and implementing this project on a national scale; and can also conduct the outcome assessment.”
Read more about the “Healthy Gardens, Healthy Youth” project, including a list of participating Washington schools, at http://bit.ly/dNU8W5.