Issue link: http://read.dmtmag.com/i/34759
GOOD TO KNOW A research report from Kate Evans, Washington State University, and Ines Hanrahan and Tom Auvil, Washington Tree Fruit Research Commission WSU apple breeding program’s fruit evaluation system ed in 1994 to provide Washington growers with a portfo- lio of new varieties with high consumer acceptance that are well suited for Washington growing conditions. How does the WSU apple breeding program achieve T this vision? Going back just a few years, apple breeders had few tools and little new science to assist the program. Today, Dr. Kate Evans, the program leader, collaborates with an international team of scientists working in tree fruit genetics, genomics, and breeding (GGB). Team members, working with WSU in Pullman and the U.S. Department of Agriculture in Wenatchee, Washington, are interna- tional leaders in their fields. They bring the latest technol- ogy to the program and help develop methods to implement the technology for the benefit of the breeding program. One of the first benefits of the genetics research is to be able to fully characterize the parent varieties using molec- ular markers that are linked to important traits and there- fore be able to make more informed decisions about he Washington State Univers - ity apple breed- ing program was establish - which two parents to combine in the crossing program. These markers can also be used to screen the seedlings to determine which have inherited the trait without having to grow a tree and wait for fruit. Seeds from the crosses are harvested and planted in the greenhouse. Some are tested for resistance to fire- blight, and any susceptible seedlings or those with severe mildew are discarded. As the effectiveness of the genetic markers identified has improved over the last couple of years, they are being used to screen the seedling popula- tion prior to planting outside in a nursery row. After plant- ing out, the seedlings are grown until the wood and buds are large enough to be used in budding onto precocious rootstocks (Malling 9 T337). Genotypes that have spines, indicating low yield potential, and severely mildewed trees are discarded. The trees are transplanted to the seedling orchard at a WSU research farm in year five after the cross is made. This is Phase 1 of the five phases in the breeding program. Phase 1 Selections are made from Phase 1 trees based on appearance and fruit quality. A series of instrumental and sensory tests are completed on fruit at harvest, and after two and four months of regular cold storage. The most promising genotypes are identified over the course of three to four fruiting cycles and are advanced to Phase 2. Phase 2 Phase 2 plantings are in three different climatic zones in Washington and are replicated for statistical evalua- tion. Industry standards such as Gala, Fuji, and Honey- crisp are included in the plantings. The best of the Phase 2 selections are placed into the commercial variety port- folio to evaluate their place in the commercial line-up. The decision to advance a genotype is made annually by Evans. If no genotype meets the requirements of the industry, none will be advanced. At least 23 commercial apple varieties, not including color or spur sports, are currently produced and sold from the state of Washing- ton. In order to improve the product line of our industry, the new products from the breeding program must be outstanding and fit within the existing variety portfolio. An Industry Advisory Council participates in the apple genetics, genomics, and breeding program in several ways. Ranking the importance of traits of apple is one activity. The GGB team prepares a list of traits that is fre- quently updated, and the advisory team and GGB team members vote on the importance of the traits listed (see current list in Table 1). Of the 21 traits rated, flavor out of 30 JULY 2011 GOOD FRUIT GROWER www.goodfruit.com