Crumb Trail
     an impermanent travelogue
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Saturday, January 14, 2006

. . . them Kazak apples.

Forsline explains that central Asia—Kazakhstan and Kyrgyzstan in particular—is likely the ancestral home of familiar domestic apples (Malus x domestica) such as Red Delicious, Golden Delicious, and McIntosh.

“We tapped millions of years of adaptations to improve today’s apple,” he says.

Forsline went on seven of the trips, including four to central Asia, to collect apple material, conserve it, and, after evaluation, distribute it to breeders and geneticists worldwide. Other trips were to Sichuan, Russian, and Turkish sectors of the Caucasus region, and Germany. . .

He says the trips resulted in “at least a doubling of the known genetic diversity of apples. It turns out that this gene pool is much more diverse than we had originally thought. And what we’ve found may help make the trees stand up better to diseases.”

Among all this material, it is the Kazak samples that have become the apple of Forsline’s eye, so to speak. Especially noteworthy are accessions collected there of M. sieversii, an important forerunner of the domestic apple. (See Forum in this issue of the magazine.) . .

“Silk Road traders and their predecessors started the spread of apples from there to other parts of the world,” he says. “But the seeds they carried likely represented a narrow genetic sampling. That’s probably why today’s American domestic apples have a fairly narrow genetic base that makes them susceptible to many diseases.”

Forsline says that many of the Kazak apples lack the size and flavor needed for commercial success. “But it’s the trees’ ability to resist diseases that sets them apart. Breeders will be able to cross them with palatable varieties.” . .

Forsline says the Kazak trees showed significant resistance to apple scab, the most important fungal disease of apples, whose outbreaks blemish fruit and defoliate trees. “Twenty-seven percent of the Kazak accessions were resistant to it,” he says. “This makes sense, because the tree co-evolved with the disease, through natural selection.”

In addition, he led a project in which the popular Gala apple variety was crossbred with seven Kazak accessions. “This produced 7 populations of 250 seedlings each,” he says. “In one of these populations, we achieved a 67-percent resistance rate against apple scab. . .

“Also, about 30 percent of samples inoculated with fire blight resisted that disease,” he adds. Fire blight destroys apples, pears, and woody ornamentals in the Rosaceae family. . .

And it is in rootstocks that Fazio, director of PGRU’s apple rootstock breeding project, also sees great potential—especially with crosses between Kazak apples and elite American material. “This is the future of the apple industry,” he says. “Give it 5 to 7 years.”

hmmm, I guess Johnny Appleseed didn't have a lot of variety, but he continued a very old tradition.

posted by back40 | 1/14/2006 10:29:00 PM


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