Broccoli doesn't like the hot summers of the eastern United States.
The plant uses cool nights as a signal to form flower buds. On the East Coast, the summer nights generally don't cool down enough.
Current varieties need the temperature to get down into the low 60s. If that doesn't happen, broccoli will produce rough, deformed heads due to the uneven size of the buds.
"We call these ugly heads," says Thomas Björkman, an associate professor of vegetable physiology at
On the flip side, parts of the East Coast where it is cool enough to raise broccoli during the summertime, like northern Maine, are too cold for most of the year.
The crop grows best in California, which produces 90% of the nation's broccoli. The rest comes from Arizona.
This means the vast majority of broccoli must be trucked to the East Coast, where it lands on grocery store shelves about one week after it leaves the farm.
Even with the best handling practices (very careful measures are taken to make sure broccoli is stored at the right temperature and doesn't arrive bruised or discolored), you end up losing some of the vegetable's fresh quality over its five- to six-day journey across the country. Shipping is expensive too, not to mention the strain that exhaust from the transportation puts on the environment.
That's why a team of agricultural scientists, led by Björkman, was tasked in 2010 with breeding a heat-tolerant broccoli that can survive in different growing conditions in the East, from northern Florida to Maine.
The Eastern Broccoli Project, supported by a $3.2 million grant from the Department of
Recent work from scientists at growing sites in Maine, New York, Virginia, North Carolina, and South Carolina are making this vision possible, in addition to Björkman's previous research.
In 1998, the Cornell professor and his colleague Karen J. Pearson pinpointed the stage of development when broccoli was most sensitive to high temperatures. The finding, described in a paper published in the Journal of Experimental of Botany, provided the "basis for a technique that plant breeders can use to screen for heat tolerance."
"It had been unproductive to just select the broccoli that looked good," explains Björkman. Most broccoli still appeared healthy because they had not yet experienced the stress, or heat, that prevents the plant from making a flower. To create new, more resilient broccoli varieties, breeders start by selecting plants, or parents, that show a strong resistance to "ugly head" defects even when grown under heat strain.
These plants are then cross-bred in a greenhouse and the offspring is crossed again until scientists create a broccoli variety that brings together all the traits needed to grow in the Eastern region.
Many hundreds of crosses have been tried over the last several years, but only five varieties of eastern-grown broccoli have made it to market so far. In the process of adapting broccoli for Eastern growers, breeders are also looking at ways to improve broccoli's taste, color, resistance to disease, and nutritional value. The stage has been set for creating the world's best and freshest broccoli.
The project's creators hope that building a regional network for broccoli could lay the framework for other specialty crops, too, and boost the local
The biggest remaining hurdle is setting up a way to distribute the seeds to the farmers who need them and then getting consumers to accept the eastern varieties. "Our goal is to have Eastern consumers eat more broccoli," said Björkman.
For that to happen, the project has joined with three major seed companies, including the controversial agriculture giant Monsanto. For those concerned about the consolidation of control of fruits and
The next step will be to see how consumers respond to eastern broccoli. The new varieties look similar to normal broccoli, says Björkman.
And flavor-wise? "The freshness makes a difference," he said.