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Screen Shot 2014-05-02 at 4.38.13 PMChances are, what you as a fruit grower know about the science of fruit has been discovered in the last 40 years, thanks to the work of just a few ­researchers.

Early this spring, a half dozen of these key researchers—tree fruit physiologists—came together for a special Cornell University In-Depth Fruit School in Geneva, New York. They spent a full day talking to fellow scientists and about 160 growers from several states about what they’d learned by their work.

The event was organized by Cornell pomologist Dr. ­Terence Robinson, who realized, he said, “We are coming to the end of an era. This could be a unique occasion—once in a lifetime—to salute the accomplishments of men who are coming to the end of their careers.

“They have really been leaders,” he said. “They have really moved fruit growing forward.”

Robinson conceded that he didn’t apply a scientific process to choosing the six people who spoke that day. “I’m the one who picked them,” he said. “I picked people I’ve looked up to all my career— mentors from the class ahead of us,” he said.

At the end of the day, Robinson posed one question to each of the scientists that turned out to be the capstone of the day. “Each of these growers have paid a hundred bucks to hear what you have to say,” he told them. “Can you give them a summary sentence, a nugget, they can take home with them?”

DeJong’s nugget

The first to answer was Dr. Ted DeJong, the University of California, Davis, researcher who has spent his career helping growers understand peach ­production. He offered three nuggets.

• It is truly the end of an age. “For the first 15 years after I started, I had fully paid staff. That allowed me to do things no researcher will ever be able to do again. We had enough resources, enough money. Now I have no paid staff other than what I can raise the funds to support.”
Researchers today spend much of their time writing grant proposals, many of which don’t become funded, he said. That diverts their time from actual research, and staff shortages still further reduce their capacity to discover. Technology—computers and dataloggers—has helped. “Technology will never take the place of human resources,” he added.

• Trees are collections of organs—shoots, leaves, roots, and fruit—all of which make “decisions” that affect the tree’s performance, and the tree is basically just a structure that holds the organs, he said.
“People think differently about trees now than they did in the past,” he said. “Genes function at the organ level, and each organ makes decisions. Trees don’t decide to shed fruit. The fruit gives up.”

• Fruit growing should be regarded as more of a science than an art. “There are a lot of scientific principles involved in ­growing fruit, and we know many more of them now than we once did,” he said.

Johnson’s nugget

Dr. R. Scott Johnson

Dr. R. Scott Johnson

Dr. R. Scott Johnson earned his doctorate from Cornell in 1982, working with Dr. Alan Lakso, and then spent 31 years as an extension specialist at the University of California, Davis. He retired recently.

A colleague of DeJong and farm advisor Kevin Day, he worked on peach and other stone fruit nutrition and water uptake, exerting total control over water and nutrients by growing trees in pure sand in large ­containers inside a large weighing lysimeter.

During the last two years of his career, he developed a website summarizing his years of research.

“You have the ability and the technology to identify and sort out the fruit that gives consumers the quality eating experience they want each time they consume a piece of fruit,” he said.

That, in the final analysis, is the reason for all the science and the learning and the orchard work. For growers, the key question is, Can we have high yields and high eating quality? Johnson thinks they can.

Greene’s nugget

Dr. Duane Greene, the University of Massachusetts tree fruit physiologist whose career has been devoted to understanding plant hormones and plant growth regulators, focusing on fruit thinning and helping growers do it more effectively, said, “We all came along at a very unique time.”

Like DeJong, he said fruit growing has been elevated from an art to a science. “Everything happens for a physiological reason,” he said.

Lakso’s nugget

Dr. Alan Lakso emphasized that point as well. Lakso, who recently retired after 40 years of work at Cornell University, spent his career finding out how apple trees and grapevines use sunlight to capture carbon and distribute it among trunks and limbs, roots, leaves, and fruit in the partitioning process.

“Try your best to understand the principles behind what you’re doing,” he said. “The tree behaves consistently with the principles that control it. The principles remain the same. The outcomes that occur in different orchards in different places may be different, but the principles remain the same.”

Palmer’s nugget

After a long career investigating how light is captured by trees and used for growth and fruit production, Dr. John Palmer told growers that fruit growing had not been reduced to a simple recipe.
“Don’t forget the power of your eye,” he said. “If you want to understand your trees, use your eyes. Observe. See what your trees are doing, then make the changes you need to make.”
In future issues, Good Fruit Grower will provide more reports on discoveries made by these leading scientists. •