A Manila dwarf coconut palm on the grounds of the Tropical
Agriculture Research Station in Mayaguez, Puerto Rico.
Mayagüez Lab Helps Farmers in the
Mario Solar stands on his toes, reaching for a 100-pound banana bunch
hanging from a plant on his farm at Salinas, in the southern coastal area of
Puerto Rico. He cuts away the blue plastic bag that covers the bunch to
minimize insect damage and increase yields. Then he pulls off five light-yellow
bananasfour for his visitors and one for himself.
We are standing in what seems like a banana tree forest, dried leaves
crunching under our feet, thankful for the shade under the foot-wide banana
plant leaves in the 90° F air. The ground is dry, except where water has
trickled from drip irrigation tubes, creating slippery puddles of mud.
It seems like a strange place to eat a banana: the morning breakfast table
is a more familiar setting. But here we are, surrounded by plants so heavy with
fruit they are tied to each other with orange twine to keep them from
collapsing under their own weight. Here and there, a tree has toppled over
We each peel our bananas and take a bite as Soler awaits our opinion. The
fruit is soft, sweet, and warmthe same temperature as the tropical air.
We nod our approval.
"All my life I've been farming. I love it," Soler says, standing
amid his 100 acres of fruits and vegetables, an agricultural oasis in an
otherwise brown landscape.
Bananas are readied for shipment at a Puerto Rican packing
In this semiarid south coast region, the average rainfall is only 30 to 35
inches a yearabout half the average for Puerto Rico as a whole. Most of
the rain in this area falls during a 3-month period from August through
October. Now it is early June and the rain-fed riverbeds are dry.
That Soler and other farmers in Puerto Rico can grow a profitable crop in
this dry region is largely due to their own hard work. But Soler is quick to
give some of the credit to the man standing next to him. "Any problem I
have, I call him and he helps me," says Soler of Heber Irizarry, an
Agricultural Research Service horticulturist.
Irizarry points to the rows of Solers Grande Naine banana plants,
which he and his colleagues in Puerto Rico introduced from Honduras in 1982.
"You can see the uniformity of the bunches. It looks like a factory."
On this day we are seeing some of the best of Puerto Rico's food
"factory," whose production has been driven by people like Irizarry
and his colleagues at ARS' Tropical Agriculture Research Station in Mayaguez.
Since 1902, scientists there have been providing a research foundation for
tropical agriculture, helping farmers more effectively grow bananas, plantains,
sweet potatoes, yams, cassava, beans, grain sorghum, and other foods, such as
tanier, or taro root.
They have introduced or developed improved varieties of these crops and have
initiated and promoted efficient farming practices such as fertilization, drip
irrigation, bunch pruning, bagging, and the management of banana plant shoots,
called ratoons, that give growers an additional crop without replanting.
Scientists at the station have packaged these practices so that farmers like
Mario Soler can produce a profitable crop.
"We try to give the farmer a crop and a system by which to grow
it," explains station director Antonio Sotomayor-Rios.
Grande Naine is one of these success stories. In dry areas like the one
where Soler farms, drip-irrigated Grande Naine plants can yield 56 metric tons
of bananas per hectare (about 25 tons per acre). Growers are paid from $4.50 to
$6.50 for a 40-pound box of high-quality bananasmeaning an acre could
yield up to 1,250 boxes, or from $5,625 to $8,255 in gross revenue.
"There's no doubt that if they manage their crop carefully and
irrigate, they can make a profit, even with the cost of installing a drip
irrigation system," Irizarry says.
PlantainsA Major Crop
We are on our way to Isabela, in northwestern Puerto Rico, with
Sotomayor-Rios and agronomist Francisco "Paco" Vazquez, who leads the
station's germplasm project. In Puerto Rico, plantains are the second most
important crop after coffee, with a farmgate value of just under $44 million.
Plantain fruits look like large bananas, but the pulp is not as soft. Green
or ripe plantains can be fried, baked, or boiled, providing people on the
island and other areas of the Tropics with a valuable source of carbohydrates
A plantain called Maricongo accounts for about 90 percent of the crop grown
in Puerto Rico. Although a high-quality plantain, Maricongo has inconsistent
yields. By late 1995, Irizarry plans to release Superplatano, a plantain
thatif managed properlycan have at least a 20 percent higher yield
"Superplatano has great potential for export markets because its yields
are consistent, and the size of the fruit is uniform if some of the lower hands
of the bunch are pruned," he says. "It also has a softer fruit pulp
than Maricongo, and it ripens like a banana."
Davis Haden mango
We see our first fruiting Superplatano plants at Modesto Canabal's farm near
Yauco in the southwestern region of the island. Most of the area, once in
sugarcane, is now covered with bananas and plantains. Canabal is the first
farmer on the island to grow Superplatano in test plantings. He is now
harvesting fruit on 3 acres. And in early 1995, he plans to harvest an
additional 12 acres that are under drip irrigation.
Irizarry believes the station's plantain research has been instrumental in
increasing crop yields in Puerto Rico from 20,000 fruits per acre in the early
1970's to more than 40,000 today.
"In the 1970's, we pioneered the use of clonal selection in plantains
and proposed techniques to overcome the problem of yield instability," he
says. "From this program we released five superior clones after testing
them all over the island, and these had an immediate impact on increasing
yields and fruit quality."
Another plantain, called Lacknau, was found to have resistance to the corn
weevil, a major banana and plantain pest.
We reach the lab's farm at Isabela and board a pickup truck that takes us
into a field where workers are digging up sweet potatoes. There are several
piles of roots on top of the soil. Their colors range from cream to dark
"The purple variety, called Viola, averaged 38 metric tons per hectare
(17 per acre) after 135 days in the fielda higher yield than any other
sweet potato testedbefore it was released in 1990," says station
agronomist Edmundo Rivera.
Next to Viola is a pile of the cream-colored variety called Ivoire.
Agronomist Francisco Vázquez checks immature jackfruit
from the exotic fruits collection.
This is the final field trial of Ivoire before its release in 1995. Rivera
says that aside from its high yieldcomparable to Viola'sIvoire has
an unusual quality for a sweet potato: It isn't sweet. It is suitable for
anyone who doesn't like the sweetness of a sweet potato but wants a good source
of fiber and carbohydrates.
Nearby, Vazquez is growing yam plants on trellises, much like a backyard
gardener would grow pole beans. Yams are tuberous vegetables, and the poles
provide support for the heavy plant vines. But the trellises are also an added
expense for farmers.
"Yams are usually grown on trellises in raised bedsmeaning higher
labor and materials costs." Vazquez says. "But our field experiments
show that we can get 60 metric tons per hectare (27 per acre) on hilly land
without trellises," he says.
At the Isabela experiment farm, station director Antonio
Sotomayor-Rios (right) and agronomist Salvio Torres-Cardona evaluate the growth
of forage peanuts.
Sotomayor-Rios says that "yams offer perhaps the greatest potential to
offset food shortages in the Tropics, because some cultivars can be grown with
no fertilizer." The station now has 24 yam cultivars from Southeast Asia,
including two outstanding onesBinugas and Gunung--that have high yields
and resistance to leaf spot diseases, soil nematodes, and the tuber weevil.
Two tropical root crops, cassava and tanier, have also gotten a boost from
ARS research at Mayaguez. Vazquez says that in the last 5 years, the station
has screened more than 50 cassava varieties for yield and culinary quality.
Three varieties that average 28 metric tons per hectare (12 per acre) without
fertilizer are slated for release in 1995.
Tanier production is often plagued by disease, poor management, and other
problems, according to plant physiologist Ricardo Goenaga. By properly managing
soil, fertilizer, and drip irrigation, he says, growers can get 40 metric tons
per hectare (18 per acre). One grower using Goenaga's methods is Carlos
Hernandez, who planted 30 acres of tanier on his farm in Santa Isabel. Goenaga
says growers like Hernandez can have a gross income of about $ 10,000 an acre
using these production methods.
Other crops that have benefited from ARS research at the Mayaguez station
- Sorghum. One recent variety of forage sorghum released by the
station is called Millo Blanco. It will grow up to 12 feet high and produce
about 7 metric tons per hectare (3 per acre) of high-quality dry forage over a
2-month period. This is twice the yield of comparable varieties, Sotomayor-Rios
says. It was developed for growing during both short and long days.
In cooperation with Texas A&M University, station researchers have
released 533 converted sorghum lines through the Sorghum Conversion Program.
Through breeding, researchers convert plants that are sensitive to day
length into ones that produce high yields, even when shorter winter days mean
- Beans. More than 40 dry edible bean lines have been released from
the Mayaguez station, making a major impact on bean production in the Tropics,
says Phillip Miklas, a plant geneticist. One variety, Arroyo-Loro, is the
leading bean grown in Puerto Rico. It is also a parent of Mayflower, which is
grown on about 80,000 acres in Michigan alone. Miklas is now using genetic
marker technology to transfer disease-resistance genes in bean germplasm.
- Cacao. In a cooperative project with the American Cacao Research
Institute, Irizarry is evaluating 40 grafted clones selected from 5 hybrid
families. The initial goal is to obtain a three- to four-fold increase in
yields. He says it may be possible to intercrop cacao with plantains, since
plantains can be grown side-by-side with young cacao plants, providing
temporary shade for them and additional revenue for the farmer.
- Tropical fruit. Jackfruit, mangosteen, mango, avocado, lychee,
mamey sapote, and carambola are some of the tropical fruits that Vazquez says
have potential as alternative crops in Puerto Rico and elsewhere in the
Tropics. One of the most promising of these fruits, mangosteen, is known as
"the most delicious fruit in the Tropics," but can take from 8 to 15
years to bear fruit. Scientists at the station developed a way to graft it onto
rootstock, allowing the tree to produce fruit within 3 to 5 years. By
Sean Adams, ARS.
Goenaga is at the USDA-ARS Tropical Agriculture Research Station, 2200 P.
A. Campos Ave., Suite 201, Mayaguez, PR 00680-5470, phone (809) 831-3435, fax
(787) 831-3386; and
Miklas is at the Vegetable and Forage Crops Research Laboratory, 24106 N
Bunn RD, Prosser, WA, 99350-9687, phone (509) 786-9258, fax (509) 786-9277.
"Mayagüez Lab Helps Farmers in the
Tropics" was published in the
January 1995 issue
of Agricultural Research magazine.