Root Crops in South East Asia and Oceania

The underutilized root crops of South East Asia and Oceania have much potential in terms of processed and fresh products. These crops are consistent with maintaining fragile ecosystems and have a potentially high output per hectare compared with other vegetables, particularly on marginal land. They are often highly relevant to agro-climatic conditions as well as to small farm production. In addition, they play a major role in the food security of this region.

Root crops have been traditional staples for thousands of years, and even today form the mainstay of many economies. Their vital contribution to people’s welfare and countries’ GDP has never been questioned, but efforts to conserve the wealth of germplasm and improve the crops for subsistence and commercial potential have been largely unfulfilled.

New approaches to the conservation and use of germplasm are being developed for the endemic root crops of South East Asia and Oceania. The question is how countries, with modest research capabilities, can take advantage of the root crop germplasm available through the development of regional crop networks.

Two regional rootcrops networks are now supported by the European Union INCO-DC Programme (DG XII):

1 - the Taro Network for South East Asia and Oceania: TANSAO

2 - the South Pacific Yam Network: SPYN

The overall objective of the network is to enhance the competitive position of taro in cropping systems of Southeast Asia and Oceania and to select varieties with high commercial potential, as a table food and when processed. This will be achieved by improving quality and resistance to pests and diseases, and by increasing the efficiency of production.

The member countries:

• Indonesia msprana@indo.net.id
• Malaysia tcyap@pop4.jaring.my
• Papua New Guinea dsingh@datec.com.pg
• the Philippines pardales@mozcom.com
• Thailand manoch@doa.go.th
• Vietnam vietvasi@hotmail.com
• Vanuatu lebot@vanuatu.com.vu

working in collaboration with Wageningen Agricultural University, The Netherlands, Herman.vaneck@USERS.PV.WAU.NL and CIRAD, France, is coordinating the project lebot@vanuatu.com.vu

In many parts of Asia, taro remains an important vegetable, although no longer a staple food. Large collections exist, but they are not being utilised to make improvements in disease resistance, productivity and quality needed to promote the use of the crop. Mechanisms for sharing germplasm and information do not exist, and the biotechnolgies required facilitating crop improvements are not available to scientists. By describing and comparing collections, selections will be possible from an area of extensive genetic diversity, rationalisation will be possible making conservation easier, and by including Papua New Guinea as a partner, crosses will be made between cultivars from two distinct genepools.

TANSAO objectives are:

• to characterise approximately 1,700 taro accessions and analyse the genetic diversity using morpho-agronomic traits and molecular markers, both isozymes and AFLPs (all countries and Wageningen Agricultural University);
• to make available 170 genotypes by in vitro exchange, to broaden the genetic base of national breeding programmes (all countries);
• to identify sources of disease resistance for use in targeted crosses (not more than 50 crosses in each participating country);
• to assess the genetic diversity of Phytophthora colocasiae using isozymes and RAPDs markers (CIRAD);
• to study the physicochemical characteristics of starch from 170 selected genotypes (CIRAD);
• to identify and overcome barriers to progress in taro breeding and develop adequate breeding strategies based on data obtained from molecular and agronomical studies (all countries;
• to coordinate TANSAO efforts to enhance cooperation between participating countries and to establish an efficient means of sharing information (CIRAD, lebot@vanuatu.com.vu).

Yam (Dioscorea alata) is a crop of considerable socio-economic importance in Pacific Island countries, in particular those of Melanesia. A wealth of genetic resources exists, but attempts to conserve the germplasm and use it to solve production problems have not been successful. If solutions are to be found, they will come only through a collaborative approach and through the use of modern biotechnologies to assist in the identification of cultivars, virus indexing and in vitro conservation.

Yam has potential for increased commercial exploitation. However, several problems are limiting its development. Tuber shape is often irregular making harvest time-consuming and labour-intensive, anthracnose disease, caused by the fungus Colletotrichum gloeosporioides, is always a threat, and staking is expensive and demands materials that are often in short supply. In addition, the lack of information on starches hinders the potential utilisation of yam as a high quality vegetable. As a first step, a thorough evaluation of genetic resources of the crop is required.

SPYN, a four-year project, has been formed to enhance the competitive position of yam in traditional cropping systems of five Pacific Island countries:

• Fiji, vakabuajn@is.com.fj
• Papua New Guinea nariwll@datec.com.pg
• the Solomon Islands ibsram@welkam.solomon.com.sb
• Vanuatu lebot@vanuatu.com.vu
• New Caledonia lebot@vanuatu.com.vu

Cultivars will be selected for desired agronomic characteristics, exchanged between participants and evaluated in diverse agro-ecological environments.

Participating Pacific Island countries are joined by specialists in yam pathology from the University of Reading j.c.peters@reading.ac.uk, the Natural Resources Institute, UK and University of GreenwichL.Kenyon@gre.ac.uk &Lebas@gre.ac.uk, the SPC tomO@spc.org.fj, and CIRAD as project coordinator lebot@vanuatu.com.vu.

SPYN is presently:

• reviewing yam genetic resources in five Pacific Islands countries (New Caledonia, Vanuatu, Fiji, the Solomons, and Papua New Guinea), collecting, characterising and evaluating the germplasm to rationalise collections and to select cultivars of interest (CIRAD, Vanuatu and New Caledonia, and all countries);
• developing a computerised database containing morphological and molecular descriptors on at least 1,250 cultivars, allowing comparison and rationalisation of collections, and the selection of 150 cultivars for compact tuber shape, unstacked cultivation, tolerance to anthracnose and acceptable cooking and processing characteristics (CIRAD, Vanuatu, and all countries);
• investigating in vitro chemotherapy of yams to remove virus infections SPC and Natural Resources Institute);
• developing methods to extract DNA from yam varieties to fingerprint the core sample (University of Reading);
• surveying Pacific Island countries for yam viruses to develop indexing procedures (UNITECH, Papua New Guinea) to allow international movement of germplasm (Solomon Islands and Papua New Guinea);
• surveying Pacific Island countries to collect Colletotrichum isolates from yams, intercrops and weeds for DNA analysis to determine sources of anthracnose inoculum (Solomon Islands and Papua New Guinea);
• conserving germplasm in the Regional Germplasm Centre by active in vitro culture and cyopreservation (CIRAD, France and SPC).

The project builds on the results of work previously carried out on yams in Pacific Island countries, aiming to solve the problems which still exist by developing regional collaboration and by using modern biotechnologies developed by specialist European institutions.