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An Eye on Plants: Breadfruit (Artocarpus altilis)

As a University of Hawaii graduate student in the early 1980s, Dr. Diane Ragone became captivated with the most important food-producing tree crop in the Pacific. That tree — breadfruit — changed Diane’s life, while she transformed people’s understanding of what breadfruit could do.

dr. diane ragone studies breadfruit at national tropical botanical garden

In her quest to collect, study, and curate what would eventually become the world’s most extensive living collection of breadfruit varieties and closely related Artocarpus camansi (breadnut) and A. mariannensis, Diane recognized that achieving breadfruit’s full potential was limited by seasonality, prompting her to seek an answer to the question: Is it possible to have year-round breadfruit production?

Overcoming the Short Breadfruit Growing Season

While long-lived and easy to grow, depending on the variety, breadfruit typically has one longer fruit-bearing season followed by a shorter season over a four to six month period, leaving six to eight months of the year without fresh breadfruit.

Called ulu in Hawaiian, breadfruit has sustained people for centuries, but its lack of year-round production has been a limiting factor in achieving a reliable, steady supply and greater commercial viability. Traditionally, Pacific Islanders have prolonged the availability of breadfruit through preservation methods such as drying and fermentation.

Diane knew seasonal scarcity could also be addressed by the careful selection of diverse varieties which would better enable breadfruit to serve as a reliable staple for reducing hunger in the tropics.

The seasonality of tree crops like apples, pears, citrus, nuts, and legumes has been studied by land-grant universities and farmers for decades, but the same was not true for breadfruit, largely because it wasn’t possible to get adequate quantities of good quality, uniform planting material.

The Breadfruit Institute 

That changed as Diane curated and built the breadfruit collection at Kahanu Garden on Maui and established the Breadfruit Institute (BFI) which, thanks to its efforts in partnering with Cultivaris (Global Breadfruit), and the University of British Columbia Okanagan, to name but a few, have been able to advance the pursuit of year-round production.

In 1996 Diane embarked on a ten-year study of 150 varieties represented by 200 trees growing at Kahanu Garden. Five years into the study, Diane graphed dates for male flower production, five stages of fruiting, and yield estimates.

She examined which varieties were producing fruit month by month over the course of each year. Closely studying production peaks (between September and December in Hawaii) and dips, Diane focused on the varieties that provided fruit when others didn’t.

Genetic Diversity May Hold the Key to Overlapping Breadfruit Production

Drawing on years of records and field notes she’d recorded throughout the Pacific, Diane selected a group of 20 varieties to capture the maximum genetic diversity in order to achieve overlapping production. Each variety was examined intensively for nutritional value and other characteristics. That group was then pared down to around 10-12 varieties to be targeted as candidates for mass micropropagation and global distribution.

The Breadfruit Institute was the first to conduct such a study and today shares its methodology and offers data collection recommendations to other institutes and researchers. Additional breadfruit seasonality studies have since been conducted in New Caledonia, Fiji, Kiribati, and currently at the University of Hawaiʻi for which Diane has served as an advisor and provided trees through the Plant a Tree of Life project.

Today, as scientists report the grave environmental threats resulting from the global loss of biodiversity in the wild, after working with breadfruit for over 35 years, Diane has demonstrated the value of collecting, studying, and preserving agricultural biodiversity in order to overcome the limitations of seasonality, proving how diversity in crops can greatly enhance food security and provide environmental benefits as well.

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By: Jon Letman, NTBG

This story originally appeared in The Bulletin – NTBG's quarterly magazine for members. Support plant conservation. Click here to become a member now.

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