Tracing Mangoes’ Family Tree

MIKE WINTERSTEIN (D1098-1) introductions to Florida date back to around 1880. Historically, mango has been highly revered in southern Asia, and it’s been referred to as “the king of fruits.” Among Hindus, its leaves are ritually used for flo- ral decorations in religious ceremonies and marriages. Today it is cultivated in tropical and warmer subtropical climates in Asia, Africa, Australia, and the Americas. With more than 1,000 known cultivars, it’s been said to be the most commonly eaten fresh fruit worldwide. Ripe mango is best known for its very sweet and unique taste, and its high water content makes it refreshing to eat.

At the ARS Subtropical Horticulture Research Station in Miami, Florida, geneticist One Shoot or Two? Raymond Schnell evaluates early flowering in a mango seedling selection. Mango cultivars are classified based on the type of embryo that develops from the seed. Monoembryonic cultivars produce a single shoot, while polyembry- WILHELMINA WASIK (D1099-1) onic types germinate multiple shoots. The highly esesteemedteeme traditional early mango introductions to Florida were crop inin IndiaIndia anda Southeast mostly from the West Indies and India. AsiaAsia forfor centuries,centur mangoes Cultivars from the West Indies flowered A havehave alsoalso bbecomeecom well estab- and set fruit well under Florida conditions lished in tropicaltropic regions of but had a poor flavor. For instance, one of CentralCentral and SouthSo America the most widely grown early West Indies overover the past 500 years.years. In the United introductions was nicknamed “Turpen- States,States mangoes are grown in Florida and tine” because of its flavor; there are trace , as well as in Puerto Rico. amounts of turpentine found in some rare Introduction of mangoes into Florida varieties. and later development of a unique Florida On the other hand, the early Indian group of mangoes have been thoroughly mango cultivars were fine-flavored, but reviewed by ARS Subtropical Horticul- they flowered and set fruit poorly under ture Research Station (SHRS) geneticist south Florida conditions. So, through Ray Schnell in Miami over the past hybridization, cultivars were developed dozen years. In 1980, SHRS was formally that embody desirable traits of Indian named a clonal repository within the Na- cultivars (mainly monoembryonic) and of tional Plant Germplasm System (NPGS) Southeast Asian cultivars (mainly polyem- with primary responsibility for collecting bryonic) and are suitable for production and preserving mango and other subtropi- under Florida’s subtropical conditions. cal crop species. Mangoes belong to the genus , Charting Mangoes’ Diversity which comprises about 30 species of trop- To efficiently develop improved mango ical fruiting trees in the flowering plant cultivars, it is first important to understand family Anacardiaceae. The mango tree Fruit of the Florida cultivar Tommy genetic relationships among current Flor- is referred to as . While Atkins is just one of several hybrids that ida cultivars as well as their relationships earliest plantings of mango germplasm produce dependably over a range of to both Indian and Southeast Asian races. at SHRS occurred in the 1920s, the first environmental conditions. Schnell has been working with SHRS

14 Agricultural Research/April 2008

438956.indd 14 3/6/08 2:09:59 PM WILHELMINA WASIK (D1100-1) colleagues—geneticists Steve Brown, Cecile Olano, David Kuhn, and Alan Meerow—to use microsatellite markers to evaluate the genetic diversity in the large collections of mangoes maintained at SHRS and at the Tropical Bo- tanic Garden, also in Miami. This will help identify the genes involved in mangoes’ wide adaptation. Leaf material used in this study, The Florida maintained at the SHRS germplasm cultivar repository, was broadly categorized into produces large groups by geographic origin: Florida, fruit that tends India, Hawaii, Central America, South to be pale green to pink and more America, Africa, Israel, and the Pacific. of an elongated Plants originating from Cuba, Puerto shape. Rico, Haiti, Jamaica, Trinidad, and the West Indies were considered West Indian. The Southeast Asian group included WILHELMINA WASIK (D1101-1) plant material from Borneo, Burma, Fruit of the Indonesia, Philippines, Vietnam, Australia, Florida cultivar , a Cambodia, Laos, and Thailand. monoembryonic mango whose Closer to India characteristics DNA extraction and analysis performed include fine flavor, bright on the leaf tissue led to findings suggest- colors—such as ing that Florida mango cultivar types are red and orange— more closely related to Indian types than and a round to Southeast Asian types. Interestingly, shape. Haden is in the pedigree the Florida types were not found to be of most of the genetically more diverse than either of the Florida mango originating parental groups. cultivars. But the Florida mangoes are unique, and a subset of them has proven to have an unusually high level of production stability and environmental adaptability. Among these productive, adaptable man- goes are Keitt, , Haden, , and , all of which produce dependably over a range of environmental conditions. “Understanding this valuable genetic This research is part of Plant Genetic There was a marked difference that architecture—how it arose, its mode of Resources, Genomics, and Genetic Im- clearly separated M. indica populations— inheritance, and which mangoes have the provement, an ARS national program so much so that it separated Southeast highest rate of production and adaptabil- (#301) described on the World Wide Web Asian cultivars from all others. There was ity—will be of the utmost importance,” at www.nps.ars.usda.gov. a close relationship between the Florida, said Schnell. “It’ll be important both for Raymond J. Schnell is with the USDA- Hawaii, and Israeli clusters—which future mango breeding efforts and for ARS Subtropical Horticulture Research was anticipated by the SHRS scientists, commercial production of mango, not only Station, 13601 Old Cutler Rd., Miami, because much germplasm has been ex- in Florida, but anywhere in the world with FL 33158; phone (786) 573-7074, fax changed between plant breeders in the a similar climate.”—By Alfredo Flores, (305) 969-6410, e-mail ray.schnell@ars. three areas. ARS. usda.gov. ✸

Agricultural Research/April 2008 15

4438956.indd38956.indd 1155 33/6/08/6/08 22:10:06:10:06 PPMM