Normally Chapman Field – site of the U.S. Department of Agriculture’s Subtropical Horticulture Research Station at 13601 Old Cutler Road – is a quiet, private workplace for scientists specializing in subtropical fruits and ornamental plants.
One day a year, however, the Chapman Field research station holds an open house and welcomes the public. The 2011 event took place on June 4, attracting several hundred people to tour the facilities and view displays. Those who came were a plant-savvy lot, asking lots of detailed questions and expressing appreciation for the locally grown fruits that Chapman Field has helped to introduce to South Florida.
The visitors learned what’s behind the Chapman Field station’s perimeter fence that parallels Old Cutler Road between Coral Gables and Pinecrest: experimental groves and plantings of trees, shrubs, and grasses being tested for their adaptability to South Florida’s climate, soils, and other environmental characteristics. Those that thrive and have commercial appeal are eventually released for public use.
A gene bank
“We’re a gene bank,” explained Alan Meerow, a research geneticist whose specialty is tropical ornamental plants. “Instead of seeds, we collect and grow whole plants. It’s another way of preserving the genetic resources of important plants.”
The Chapman Field station is one of 22 national germplasm repositories. It houses national collections of cultivars (plant varieties with desirable characteristics) of mango, avocado, cacao, banana and plantain, Annona, Tripsacum, sugarcane and related grasses, palms, and some minor tropical crops.
In agriculture as in many other fields of endeavor, knowing what won’t work is every bit as important as knowing what does. On a bus trip around the station, Meerow pointed out many of the trees and plants growing there. He described the research being done with them, highlighting both successes and failures.
Avocados at risk
Of particular interest was a group of avocado trees with various combinations of colored rings painted around their trunks, testimony to the battle against the redbay ambrosia beetle. This exotic pest is believed to have entered the U.S. in 2002 through the Port of Savannah, Georgia, in a shipment of wood from China.
“The beetle bores into trees in the laurel family and farms a fungus inside the tree,” Meerow said. “In an effort at self-protection, the tree walls off its infected conducting tissue, eventually killing itself. It’s a serious problem, because many laurels are major rainforest canopy trees.”
Already the ambrosia beetle has attacked stands of red bay trees from Georgia down through Florida to the margin of the Everglades. Avocado, a major crop in Miami-Dade and Broward counties, also is in the laurel family and is at risk.
One protective measure being tested at Chapman Field is the fungicide Alamo, but Meerow cautions that it’s a “systemic” poison that enters the fruit, making avocados from Alamo-treated trees unfit for human consumption. A more helpful approach would be identifying avocado varieties with genetic resistance to the beetle and fungus, and making those resistant varieties readily available to growers.
Plant genes and fruit flies
Visitors also took guided tours of the station’s new two-story, 32,766-square-foot laboratory building. It houses sophisticated equipment that researchers use to extract DNA (deoxyribonucleic acid) from plants and identify their genes. Although this process has been known since the mid-20th Century, the early research was done using cumbersome hand-held equipment, often one sample at a time. Now, using automation and robotics, the scientists at Chapman Field can process hundreds or even thousands of samples in a single day, speeding up the pace of research.
In the building’s chemistry lab, equipment isolates and identifies chemicals attractive to the Mediterranean fruit fly, a notorious exotic pest that eats citrus and many other kinds of fruit. Chapman Field obtains sterile male fruit flies imported from a breeding lab in Guatemala.
In one series of experiments, staff member Rick Joseph cuts off the heads of living flies, attaches them to thin glass rods, and exposes them to various chemicals. A gas chromatograph-electroantennogram detector records the flies’ responses. “A severed head continues to react for about an hour,” he says.
The 2011 open house featured lychees, which seem to be all over town this year at farmers markets and front-yard stands as South Floridians enjoy a bumper crop. Nine different varieties of lychees grow at the research station: Bengal, Brewster, Calcutta, Hanging Green, Large Early Red, Mauritius, No Mai Ts’z, No Mai Tun, and Peerless.
The open-house planners intended to offer visitors a taste of each variety and then encourage them to fill out a survey to determine the three most popular varieties. The problem with their plan was that the lychees were pre-picked in advance and frozen until open-house day to keep them from spoiling.
The lychees in some of the buckets were so frozen that they weren’t amenable to peeling. Others could be peeled but were so cold that they had little or no detectable flavor. Many visitors who attempted to taste did not try all the varieties, and many didn’t fill out the survey forms. As a consequence, whatever results the survey yields won’t be particularly accurate or meaningful.
The open house also included plant sales, food vendors, and educational booths presented by state and federal agriculture agencies.
A long history
For more than a century, the Chapman Field research station and its precursors have been responsible for the introduction and development of many favorite South Florida plants and fruits.
It began as a plant introduction garden on a six-acre site near Brickell Avenue in 1898. In 1914, it moved to the Buena Vista area north of downtown Miami. In 1923, it relocated again to its present site at an Army Air Corps base named for Victor Chapman, the first American flier to die in France during World War I.
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