Mild Winter Aids Blueberry 'Fake Chill' Research

By for CAES News

This winter's mild temperatures have blueberry farmers wondering if their plants will bear a full crop this year. But two University of Georgia scientists say the low chill hours could aid research that could greatly help future crops.

"Dormex is a plant growth regulator that can replace some of the chill hours blueberries need but don't get in many years," said Gerard Krewer, an Extension Service horticulturist with the UGA College of Agricultural and Environmental Sciences.

"We don't like having a low-chilling winter," Krewer said. "But it's been a great research year."

Blueberries, like most fruits, need a certain number of chill hours (below 45 degrees) to break their dormancy and produce flowers to make a crop.

Following a low-chilling winter, Krewer said, some blueberry varieties bloom and set fruit before leafing. Once the berries begin to grow, this further suppresses leaf bud development.

But the leaves are just as important as the flowers, said Scott NeSmith, a UGA research horticulturist at the Georgia Experiment Station in Griffin, Ga.

"If the plant flowers, it can set fruit," he said. "But without leaves, the plants can't photosynthesize and make energy to keep and support the berries."

NeSmith said Dormex "retrofits" many blueberry varieties "instead of forcing farmers to wait for new varieties with lower chilling requirements."

Developing new varieties can take upwards of 15 years and thousands of dollars, he said, for the research alone.

"For now, this is a good solution," NeSmith said.

For the most part, he said, Dormex will help assure growers of having blueberries when prices are higher. For shoppers, it means having the high-quality Georgia blueberries they want.

Dormex leaves no residue, either, Krewer said. It simply breaks down into fertilizer and water.

NeSmith, Krewer and a number of county Extension Service agents have been studying Dormex for 10 years. "Results on peaches have varied," Krewer said. "But blueberries have responded very well."

The Environmental Protection Agency has approved Dormex only for experimental use. But Krewer is optimistic farmers will be able to use the product during the 1999 season.

"This is just about a miracle compound for poor-leafing, early-season blueberries," he said.