Central Washington Apple Breeding
On November 18, Dr. Kate Evans, a Professor of Washington State University, presented her research on DNA-informed apple breeding. Her seminar focused on the improvement of apple cultivars suited for the dry environmental conditions of Central Washington.
Dr. Evans divides her apple-breeding program into three phases in order to get an identifiable candidate for new cultivar release. DNA-informed apple breeding is the focus of Dr. Evans’s work. She looks at the genetic susceptibility of apples to certain diseases as well as consumer preferred apple appearance and eating qualities.
In phase one, she selects a potential new cultivar from crossing of two parental lines. The obstacles in this phase include limited fruit quantity leading to limited quality evaluation. The second phase involves vegetative propagation of the single candidate. Five trees of the new cultivar are then grown in three different Central Washington locations that are representative of variable growing conditions. Additionally, reference cultivars are also planted for comparison purposes. This phase makes it possible to evaluate fruits from several harvest dates. Finally, the third phase is the most extensive from the top selections.
In the third phase, the research group plants 50-75 trees from the original single candidate in up to four different field locations. They collect mature fruits and place them in cold storage for two months followed by non-cold shelf storage for one week. To quantify the traits of the new cultivar, sensory testing and instrument-based evaluations are conducted. Sensory testing includes the assemblage of experts who can assess fruit quality. The instrument-based evaluation involves utilization of lab technology in order to provide an unbiased testing procedure.
Quantitative parameters include repeatability, appearance, and eating quality . Repeatability looks at the varying genetic factors that influence a particular trait. Consumers mostly choose fruits that are appealing in appearance and eating quality. The texture or crispness of the apple is another key component of apple desirability. Other parameters are juiciness, sweetness, acidity, and aroma.
If a selected seedling passed all the described testing, breeders recommend this new cultivar to farmers. The cultivar becomes available to all apple farmers in Washington State. Brand placement becomes a key component of potential apple sales before release into stores. The drawbacks of the process are that apple enthusiasts must wait an extended period of time before a new cultivar becomes available for them to consume and enjoy.
Hardner C.M., Evans K., Brien C., Bliss F., & Peace C. (2016). Genetic architecture of apple fruit quality traits following storage and implications for genetic improvement. Tree Genetics And Genomes, 12(2). doi:10.1007/s11295-016-0977-z