New Agriculturist: Focus on - Agrobiodiversity challenges in the Pacific

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Agrobiodiversity challenges in the Pacific

Agrobiodiversity challenges in the Pacific

CePaCT supports a breeding programme for taro that is helping to get new varieties growing again in Samoa
SPC

The Pacific islands face some unique challenges, and this is certainly true when it comes to agrobiodiversity. Across the world's biggest ocean, 22 island states comprise at least 20,000 islands, and each has its own distinct growing conditions. The crops that are grown today are mostly descendants of those that arrived by canoe with early colonisers - taro, yam and bananas were carried as roots or suckers, in much the same way as these crops are propagated today. But, going west to east, diversity of these crops falls markedly, as fewer migrants reached the more remote easterly groups. And, because they are mostly vegetatively propagated, there was little scope to increase genetic diversity once the crops had arrived.

The ocean barrier which has limited the spread of biodiversity offers an amount of protection to its island ecosystems; yet when that barrier is breached, the fragility of these ecosystems is revealed. Whether taro leaf blight arrived in Samoa on the wind or by ship in 1993, all taro varieties proved susceptible and the islands' entire crop was destroyed, along with the livelihoods of thousands of smallholders and the country's main agricultural export industry. This graphically illustrates the risk that low agrobiodiversity poses.

"With agricultural intensification, and especially the focus on supplying markets, crop diversity is being further eroded," says Dr Mary Taylor, who has worked with genetic resources in the Pacific region for the last 20 years. "We need to build resilience of island communities by increasing crop diversity. The pest and disease threat is one issue, as Samoa demonstrated - climate change is another. Adapting to rapidly changing climate conditions is going to need all the diversity we can muster."

CePaCT - a regional gene bank for the Pacific

CePaCT holds unique collections of regionally important crops
SPC

Increasing crop diversity depends on genetic resources being both available and accessible, and this has been the focus of Taylor's work, as manager of the Centre for Pacific Crops and Trees (CePaCT), the regional gene bank. "In the past, many Pacific island countries had their own, mainly field, gene banks. But because resources were limited these weren't always maintained, and they were also vulnerable to pests and diseases and to extreme weather. Many collections have been lost over the years." The regional gene bank was set up in 1998, and September last year saw the opening of a new state-of-the-art facility in Fiji. "The new genebank provides a repository for the entire region's collections, and also facilitates access to that diversity, both within and outside the region," says Taylor.

CePaCT holds a unique collection of 878 accessions of taro, as well as other regionally important crops such as yam, sweetpotato, banana, breadfruit, cassava, kava, aibika and black pepper. As well as safely conserving the region's genetic resources, CePaCT is working with country partners on crop improvement programmes, and promoting sharing through partnerships and networks. The Centre is the first outside the Consultative Group on International Agricultural Research (CGIAR) system to obtain long-term funding from the Global Crop Diversity Trust, specifically for the taro and yam collections.

Sharing within the region

"Perhaps more than any other region, the Pacific islands need to cooperate over genetic resources," explains Taylor. "Few island states have the personnel or other resources to manage their own collections. And if an island loses a whole crop, as in Samoa, then it needs to look outside for new genetic resources to start again."

Tissue culture plants are the safest way of sharing of genetic resources
SPC

CePaCT supports a breeding programme for taro that is helping to get new varieties growing again in Samoa, as well as across the region. The programme has generated crosses between Asian and Pacific taro, bringing new genetic diversity to the previously narrow taro genetic base in the Pacific.

Tissue culture has been a key technology in the sharing of genetic resources in the region. Used with effective virus testing methodologies, tissue culture plants are the safest way to transfer planting material from one country to the next. "Countries rightly protect their crops with strict quarantine laws," says Taylor. "With tissue culture we can guarantee virus-free status, and can import new genetic diversity into countries safely." Tissue culture also facilitates multiplication and distribution of new varieties.

Beyond the region

The Secretariat of the Pacific Community (SPC), which hosts CePaCT, has been instrumental in building trust between Pacific island nations to facilitate sharing of genetic resources. But the urgent need for increased crop diversity means going beyond the region and sharing globally. In June last year, the CePaCT collections were placed under the International Treaty on Plant Genetic Resources for Food and Agriculture. "The Pacific islands can benefit enormously from access to worldwide genetic resources," says Taylor. SPC and CePaCT are providing support to Pacific countries to implement the Treaty, so that the region will indeed be able to muster all available crop diversity as it faces the future.

Written by Anne Moorhead

Date published: March 2010