ICARDA Caravan 4

(GPS) receiver, used to establish exact position from satellites.

The hunt is on, scanning the environment for appropriate ecosystems. A stop and search all too often ends in disappointment. A sixth sense must be cultivated. Sometimes a chat with the local inhabitants will reap rewards. Even though they might not know the scientific name, they will sometimes recognize the plant from a picture and point you in the right direction. A wise collector will also inspect a few areas which do not correspond to his or her idea of the characteristic habitat, just to make sure that s/he is on the right track and that the ecological preference of the species is no less specific than originally thought.

Shrieks of delight erupt as one of the team spots a fragile lentil. Closer examination in the immediate environment usually reveals a few more plants, occasionally a couple of hundred, but usually in a very restricted location. If the team is in luck the pods won't have shattered, and the seeds will be easy to collect; otherwise they will be down on their hands and knees with a pair of tweezers, looking for soil-colored seeds of no more than 4mm in diameter. Fortunately there is no problem in keeping the seed viable until the end of the collection mission, as there is with some other species; the seeds of wild lentils are adapted to survive the summer months at very low moisture content. But, with such small populations, the collector must be careful. Excessive sampling from a small population may endanger its very existence. After finding the population, the collectors may have to leave empty-handed!

A site number is allocated, and a unique identifier known as the collector number which will accompany the seed sample when it is distributed to users around the world. Exact site location is recorded, as well as a site description including the slope, the soil depth, aspect, soil texture and the nature of the parent rock. The size of the population, the area over which it is distributed and an indication of the threat to the population such as the proximity of agricultural activities and the grazing pressure are also recorded. All this is known as the passport data. Soil samples are taken for analysis, an entire plant is flattened in a plant press for the herbarium, a Rhizobia root nodule is carefully stored in silica gel for culture and inclusion in the Rhizobium collection. Then, with no time to waste, the team is back on the road, scanning the environment, searching for that ecosystem. A typical expedition usually last a couple of weeks, and will include moments of both depression and delight.

Before the mission leaves the host country, the seed is divided. Half will remain in the national genebank, and half will be taken back to ICARDA for international distribution. Back at ICARDA, the seed is inspected by the Seed Health Laboratory for insects and diseases, and a part of the original seed is planted for multiplication in a quarantine area. The new accession is given an ICARDA identity number, and the passport data collected on the expedition is entered into a database. Eventually some of the multiplied seed is dried to a low moisture content of 5-6%, vacuum-sealed in a fabricated aluminum foil packet and placed in the base collection at -20°C. Here they can be stored for 50-100 years. The rest of the seed will be maintained in the active collection at around 0°C and 15-20% relative humidity, and used for distribution.

Over the following few growing seasons the material will be characterized and evaluated for traits of interest.

Germplasm is maintained under the auspices of the Food and Agriculture Organization (FAO), and, under the requirements of the Convention of Biological Diversity, make it freely available for all bona fide users with the restriction to recipients that they do not take out variety protection rights nor will patent any naturally occurring genes from germplasm provided, without the consent of the country of origin. The common heritage of humanity is thus conserved for future generations.

Morag Ferguson was an associate researcher at ICARDA until becoming a lecturer at Southampton University, Britain, in September 1996.

Her work at ICARDA was sponsored by Britain's Overseas Development Agency (ODA).

ir Joseph Banks (1743-1820) was president of the royal

gardens at Kew, and an intrepid plant collector who sailed with Captain Cook. He spoke of the "dedication required for plant hunting, the single-mindedness, the stamina and cheerful indifference to discomfort and to continuous disappointment." Less polite variations of these words ring in the ears of ICARDA plant collectors as they grapple through bushes and entangled undergrowth day after day, battling with snakes and potentially rabid dogs in their quest for their elusive treasure--genetic diversity. And that includes the wild relatives of lentils.

Lentils provide a valuable source of protein and calories for millions of people in South Asia, West Asia and North Africa. They are thought to have been brought into cultivation somewhere in southeast Turkey or northern Syria near the Tigris and Euphrates rivers. The crop was domesticated from a wild lentil species which grows naturally in the area (L. culinaris subsp. orientalis). This wild progenitor still exists in the region and further afield. There are currently three additional wild taxa which are also closely related to the lentil and share the same genus. They are L. odemensis, L. ervoides and L. nigricans. Together they contain a huge reservoir of genetic variability which can be used in lentil-improvement programs. These wild species are, however, at risk from genetic erosion, primarily through habitat destruction. It is essential that these genetic resources are collected and conserved. There is no way of telling what tomorrow's needs will be, and what genes may be required to meet them. The problem is finding them!

Detective work is needed, and a bit of luck. Preparation must start well in advance of the expedition. A target area and a target species must be decided upon. This could be based on: a known area of high genetic diversity; or unique genetic diversity; an area which is under-represented in the collection; a need for a particular attribute, such as salt tolerance or cold tolerance; a region in which a species is particularly at risk; or a particular request from colleagues in other institutions or governments.

The collection team must be appointed and an agreement signed with the appropriate national program. Once this is done, the plant collector must gain as much information as possible about where and when to find the target species in the selected area. This largely centers around determining the characteristics of the preferred ecological environment of the species and includes information on soil type, topography, geology, temperature range, water relations, its ability to withstand grazing pressure, and information regarding other species with which it is likely to be associated. Information can be gleaned from floras, past expedition reports, from existing passport data (see below) and from climatic and vegetation maps.

Timing is crucial. The seeds must be ripe for collection. This is particularly important in the case of wild lentils, as the pods shatter to disperse their seed. The expedition must be timed to catch the pods just before they shatter. This is never easy, as the time varies from year to year and site to site. To fix it, the collectors need up-to-date weather reports from the region right up to the date of departure. It may even be necessary to carry out an initial survey to locate the populations in a specified area prior to collection.

The collector must also have a sampling strategy in order to maximize the genetic diversity that is collected. This should be based on a knowledge of the genetic structure of the population, how much genetic variation exists between seeds of a single plant, between seeds of different plants, and between populations.