Conserving, promoting and improving crop diversity to enhance food security in a changing climate

October 17th, 2008

Swamp taro (cyrtosperma merkusii) in Pohnpei, Federated States of Micronesia (Mary Taylor)

Traditionally Pacific Islanders have used different ways to ensure food security, such as gardening, fishing, hunting and selling products or labour to provide an income. However with the increase in urbanization and cheap, poor quality food imports, local food production has been negatively affected. Climate change will also affect food production and other factors, such as health, infrastructure, ability of countries to import food and ability of households to purchase food. As a result food security will be threatened.

The Pacific region is already prone to floods and droughts. Water for agriculture is supplied almost entirely by rainfall, rather than by irrigation, therefore any changes in the frequency and intensity of rainfall events will have an impact. The prediction is for more rainfall in the summer, the traditional wet period, and less in the already dry months, highlighting difficulties for sustaining crops throughout the year. At the same time, rainfall events are likely to be more intense and possibly less frequent, with predictable implications for flooding and drought. Heavy flooding of the Wainibuka and Rewa rivers in Fiji in April 2004, for example, damaged between 50% and 70% of crops in the area. Increasingly extreme rainfall, coupled with ongoing deforestation and longer dry spells, may also affect soil fertility. In coastal communities the effects of erosion, increased contamination of groundwater and estuaries by saltwater incursion, cyclones and storm surges, heat stress and drought may individually or in combination undermine food production. Cyclones are a significant cause of lost agricultural production – Cyclone Ami, for example, caused over US$35 million in lost crops in Fiji in 2003. There is also the likelihood of increases and/or changes in pest and disease problems, and changes in the respiration/photosynthesis balance of crop plants resulting in reduced yields.

Traditionally Pacific Island communities have grown multiple crops, an agricultural practice which makes food supply resilient, as not all crops are affected by specific climatic extremes such as droughts or cyclones. However, with the influence of various factors, such as export markets, increased urbanization, the diversity and intensity of local production in most countries has weakened. This situation has been further highlighted by the current food crisis. Many Pacific Island countries are very reliant on imported foods and so are vulnerable to any changes in the production and supply of those foods. Increasing local food production is one way in which to buffer these external shocks, but the influence of climate change cannot be ignored, if any increase in local food production is to be sustained.

Alocasia collecting in Tonga (Mary Taylor)

Alocasia collecting in Tonga (Mary Taylor)

Climate change places demands on the crops that we grow – crops and varieties are required to withstand unpredictable biotic stresses, such as drought, salt, high temperature and water-logging. Farmers in the Pacific need to be able to plant crops/varieties which they know will be productive despite the vagaries of the growing season. Different crops and varieties, provides them with a “toolkit of diversity” with which to plan for, and react to the changes in the climate

We do have in the Pacific region, crops and crop varieties, with known tolerance/resistance to these biotic demands, such as some aroids (Xanthosoma, Alocasia and swamp taro). In addition some varieties of the Pacific’s major crops, such as taro, sweet potato, banana and cassava have been recognized as having drought and/or salt tolerance. However, access to them by farmers, often in the country in which they exist, and in other Pacific island countries, is not guaranteed. In some cases, the fact these crops/varieties have these desirable traits is not widely known, the result, generally, of poor documentation. Availability of planting material is also a constraint – many of these crops/varieties are not in a central location to facilitate distribution and, there are usually problems with the supply of planting material.

Establishing a “climate ready” collection in the Centre for Pacific Crops and Trees
The Secretariat of the Pacific Community Land Resources Division (SPC LRD) hosts a regional genebank, the Centre for Pacific Crops and Trees (CePaCT), where collections of the major food crops in the Pacific are conserved in vitro. The CePaCT is recognized internationally for its unique taro (Colocasia esculenta) collection of over 760 accessions, and its work with other crops, such as yams. The CePaCT is working with partners in the member countries to identify crops and varieties with tolerance to extreme conditions, for the establishment of a “climate ready” collection, in vitro. After virus testing this collection will be accessible by all SPC member countries.

Xanthosoma collected from Tonga

Xanthosoma collected from Tonga

SPC is also in the process of establishing an agreement with the Secretariat to the International Treaty on Plant Genetic Resources for Food and Agriculture (ITPGRFA) to place all of its ex situ collections into the Multilateral System (MLS) of the Treaty. As such, SPC is currently seeking approval from its member countries to do this, and assuming countries are in agreement, the placing of all of CePaCT’s ex situ collection in the MLS, would mean that the “climate ready” collection would be globally accessible.

As well as accessing genetic resources from within the region, CePaCT is also looking outside the region, mainly to the International Agriculture Research Centres (IARCs) to import new, improved varieties for farmers of the region to evaluate. In establishing a “climate ready” collection, CePaCT will link with relevant IARCs to obtain crops and varieties with greater tolerance to stresses such as drought and heat. The IARCs have the capacity to use advanced molecular techniques, enabling them to identify and select for genes controlling stress tolerance. These techniques are especially important for successfully transferring desirable traits from crop-related wild plants into commercial varieties of domesticated species. For example, researchers at the International Tropical Agriculture Institute (IITA) in Nigeria are evaluating cassava in the semi-arid regions of East and West Africa to determine what mechanisms enable the crop to withstand dry spells. Using the tools of molecular biology, the genes for this trait can be identified, which will further enhance the drought tolerance of cassava.

The main focus areas in establishing the “climate ready” collection are as follows:

  • Collecting in the countries of crops and varieties of the more-known crops, such as taro, yams and bananas, with desired “climate-ready” traits, such as drought, salt, high temperature, water-logging tolerance: this collecting activity will be linked to a prior consultation with the countries to discuss which crops and varieties are “eligible” for this collection.
  • Under-utilized species and wild relatives will also be considered. Under-utilized species offer much potential for managing climate change and ensuring food security either through domestication and local food production and/or niche markets. SPC has carried out some work in this area with a small study on a local fern in Fiji. There is much concern globally for the capacity of wild relatives of crop species to survive climate change. These same wild relatives could hold the resistant traits we require in our cultivated plants. There is no strategy in the Pacific to conserve and evaluate the wild relatives of our major crops, which exist mainly in the Melanesian countries, and are already under threat of erosion by activities, such as logging. Such wild relatives could be very used in either conventional or modern breeding programmes, and as such, need to be identified, conserved and evaluated.
  • The CePaCT distributes plants to the SPC 22 Pacific Island countries and Territories (member countries), all with specific quarantine regulations. Prior to any distribution and evaluation, plants have to be virus tested.
  • The CePaCT will make every effort in the consultation process through the Pacific PGR network (PAPGREN) to only bring into CePaCT crops and varieties where desired traits have already been identified. However as the collection will exist of material obtained from different Pacific Island countries and territories, as well as from the International Agriculture Research Centres, evaluation in the countries will also be required. This will be carried using existing networks and programmes, such as the participatory farmers’ group in the Taro Improvement programme in Samoa. The CePaCT has recently held discussions with the Ministry of Agriculture in Fiji to embark on a programme for screening Fijian crop diversity on a nearby atoll.


Mary Taylor (Dr)
Genetic Resources Coordinator/Centre for Pacific Crops and Trees Manager
Secretariat of the Pacific Community
Private Mail Bag
Suva – Fiji
Tel No: (679) 3370733 Ext 271
Fax No: (679) 3370021