Jan 3, 2011
Finding right genes could speed up apple breeding

In the last decade or so, apple varieties – even traditional varieties like Red Delicious – have gotten better. Traits like taste and pressure have improved. Tools that weren’t available even 10 years ago – 1-MCP, Retain, CA storage – along with a greater understanding of the best ways to grow, harvest and store fruit, have increased the quality of apples in general, said Todd Fryhover, president of the Washington Apple Commission.

As helpful as those new tools have been, they haven’t managed to speed up the breeding process. It still takes years for a breeder to learn if an apple variety has the right characteristics for the marketplace. Even if it does, decades can go by before the variety is ready to be marketed and sold. From the first cross to the final release, the entire process can take up to 30 years. Growers and retailers don’t want to wait that long.

As a cherry breeder for Michigan State University, Amy Iezzoni is familiar with the frustrations and long waits apple breeders experience. If there were some way to test a variety for its commercial potential beforehand, instead of waiting years for seedlings to grow, it would save a lot of time and money. Such testing would allow a breeder like Iezzoni to concentrate her resources on more promising varieties, and pump those out faster than has happened in the past.

The secret to speeding up the breeding process most likely lies within the apple’s genes. The genetic approach is new to apple breeding, but Jim McFerson, manager of the Washington Tree Fruit Research Commission, expects to see more of it in the next few years.

So does Iezzoni, who’s also director of the RosBREED project. RosBREED is a collaborative effort to speed up the development of fruit in the Rosaceae family. Apples, peaches, cherries and strawberries are part of that family and share many genetic traits.

USDA provided $7.2 million to fund RosBREED – matched by in-kind funding from participating institutions and organizations, for a total budget of $14.4 million. Twenty-seven people from 12 universities are participating in the project, which is in the process of surveying breeders, growers, packers, shippers and everybody else in the chain about what kind of traits they’re looking for in rosaceous fruit. It will take some time for all the data to be compiled, but the end result should give breeders better direction in the future. Some of the data will be ready by the time RosBREED participants meet in East Lansing, Mich., in March, Iezzoni said.

Of great help to apple-breeding efforts: The apple genome (the totality of its genetic information) was just recently sequenced. This breakthrough will “allow scientists to more rapidly identify which genes provide desirable characteristics to the fruit and which genes and gene variants provide disease or drought resistance to the plant,” according to Washington State University.

There’s still a huge gap, however, between sequencing the apple genome and the practical application of that knowledge. Iezzoni and others are starting to close that gap, looking for the “jewels in the genome” – genes that control traits like flavor and texture, she said.

Of course, genetically modifying fruit is not without controversy. Some people are “freaked out” by the idea, considering it unsafe, but attitudes seem to be improving. The genetic approach has so much potential, it’s not something that can be easily discarded, said Kate Evans, the head of Washington State University’s apple breeding program.

David Bedford, an apple breeder with the University of Minnesota, said the apple varieties currently in the marketplace represent only a “tiny bandwidth” of the potential in the fruit’s germplasm. We might see some very interesting apples in the future, he said.

Matt Milkovich

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