June 5, 2008
The time is ripe for an apple that tastes like berries and one that doesn't brown
Mention an apple and most people will immediately associate the word with a crisp, juicy, sweet-tart red fruit. But ask Cornell fruit geneticist Susan Brown about apples, and she'll share visions of deep red flesh or skin patterned like feathers on a bird's back, of flavors like anise, berries or roses. She'll talk of apples loaded with cancer-preventive antioxidants or as much vitamin C as an orange, that don't brown when cut or go soft in storage.
At the New York State Agricultural Experiment Station (NYSAES) in Geneva, N.Y., these apples already exist, and new possibilities -- whether exotic, delicious, kind of weird or just plain awful (think gasoline, nail-polish remover or soap) -- are literally endless.
Every seed holds a mystery
Apples are as infinitely variable as the number of seeds they produce the world over, and planting a seed will never produce a tree just like the one it came from. Though a tree confers the same qualities on all the apples it bears, the five to 10 seeds inside each apple are all unique offspring.
The only way to replicate a desirable apple is to graft a cutting from the tree that produced it onto some sturdy rootstock, explains Brown, the Herman M. Cohn Professor of Horticultural Sciences. The trees that yield the varieties popular with consumers are all clones of solitary originals that, in the old days at least, probably grew by chance in a cider orchard or wilderness.
Though chance and intuition will always play a role in the birth of some great apples, creating superior new varieties that will catch on with consumers involves a heavy dose of science.
The apple-breeding program at NYSAES dates back 125 years and has reaped 63 cultivars, including the Empire, Macoun, Jonagold and Cortland.
"When I came into the program in 1990, I realized that a lot of our varieties were based on McIntosh or Empire because they are ideally suited to our location," Brown says. But she was concerned about the lack of genetic diversity in commercial apples. "I have really sought to save traits that I think will add to our knowledge of genes and how they can be deployed. The rootstock breeding program also does this."
Brown arrived at Cornell just as revolutionary advances in molecular genetic technology were sparking the College of Agriculture and Life Sciences-led Genomics Initiative, now known as the New Life Sciences Initiative.
"In 1990 there were probably only 28 families of genes," Brown recalls. "A family of genes would be, for example, several genes for scab resistance. We didn't have a lot that we could use to make more efficient what was admittedly a long, expensive process. But now we have genetic markers that we can use. I can show you a small seedling and tell you whether that little seedling, when it grows up, is going to have red or yellow fruit, or have a gene for disease resistance or not. I can get scab resistance without any problem at all."
Brown also hopes to make the apple business more profitable for the state's 674 growers. She works closely with New York stakeholders, both to find out what improvements they would like to see in apples and to have their help with grower trials of promising new varieties. "We have fruit in grower trials pretty much all throughout New York," she says.
She also works to create trees that not only produce well but successfully resist multiple insect pests and pathogens, and do it all while beautifully enhancing a variety of landscapes.
Apple trees, it turns out, don't have to look like a trunk with upward, out-spreading branches. Brown has fruit-bearing trees that are perfectly columnar, others that weep and some crosses of these types that are both columnar and weeping. Her favorite type looks like a bush, with dense, upward-thrusting branches of uniform length. "All the branches stop at almost the same point," she notes. "We spend a lot of time pruning trees, trying to bring them down so that growers can get in there with ladders." She even has one that is only a foot high and already bearing fruit.
With so much of the apple's enormous potential yet to explore, she and her colleagues are excited about beefing up Cornell's tree-fruit genomics program with three new genomicists, the first of which will be an expert in the genetics of tree architecture.
"Our goal is to establish a center in tree fruit genomics," she says. "We have the USDA germplasm repository, with more than 2,000 accessions of apple, my breeding program, the rootstock breeding program, and the USDA grape group in the next building is a center of excellence in grape genomics," she says. In addition, "Every year we harvest at least 10,000 seeds. We have 33 acres of seedlings, which is a huge amount, and we have to evaluate them for many characteristics. We're one of the largest programs in the world."
Another goal for Brown is to create an apple that can convert a new generation of children to eating fruit. She got an idea about what might work when she put crabapples in her kids' lunches as a joke and they came home raving about how good they were. "Kids like more fully flavored apples with higher acidity -- that's how Granny Smith became popular," she says. "My goal is not to get kids to eat crabapples but to develop large varieties that are really powerful. I want to make apples that are really desirable to the younger market, because if they don't eat them now, then they're never going to eat them."
And if they don't eat them, there's no end to what they'll be missing.
This article has been abridged from College of Agriculture and Life Sciences News.