Introduction

The maintenance of health by means of various techniques and substances is almost as old as the history of human evolution itself. Although the resources available were easily drawn from the natural environment, their efficacy for solving problems which reduce life expectancy was established only through rigorous trials over a considerable period of time, often involving Man himself as subject of the experiment.

Our ancestors, and millions of people in modern Africa, have relied heavily on plants, animals and minerals to ward off pathogens and to maintain the functional balance of each organ. Many species of plants had to be tested and retested in the endless search for drugs that could prolong life or, it was believed, even confer immortality. Many plants have been found to possess the desired effects as a result of well planned experiments, while some discoveries were just a product of serendipity. Many sacrifices had to be made, however, not only in terms of money and time, but also in terms of human lives.

Until a generation or two ago plants were the primary source of health care for entire populations in most African countries and such plants still remain important sources of drugs for nearly 80 per cent of the population in contemporary Ethiopia. In spite of this we still know very little, whilst many Africans who receive their education abroad believe that imported drugs are always superior, even if these are unaffordable to the large majority of the population.

Introduction

The quantity and complexity of the information acquired by the Plant Genetic Resources Centre/Ethiopia (PGRC/E) through active collecting, donation and repatriation of germplasm require comprehensive and efficient data management systems. Plant genetic resources can only be successfully utilized if detailed and reliable data on each accession are available to genebank users, breeders, research workers and policy makers.

In 1979, a proposal was made to base such a documentation system on edge-punched cards (Engels, 1979) and this manual system was used until 1982, by which time the amount of data had reached such proportions that the system was overcharged and it became necessary to computerize the documentation activities (Engels, 1985).

At present the documentation system at PGRC/E is based on electronic data processing technology and this has greatly facilitated the handling of the enormous amount of data currently being generated at the centre.

Information sources and descriptor development

The major sources of information in PGRC/E are:

1. – exploration and collection;

2. – germplasm introduction and accessioning;

3. – temporary storage (at +4°C and 30–40 per cent RH);

4. – field genebanks;

5. – multiplication and rejuvenation;

6. – characterization and preliminary evaluation (in field and laboratory);

7. – seed processing;

8. – seed testing;

9. – seed storage (base and active collection at –10 °C);

10. – germplasm flow;

11. – further evaluation;

12. – utilization;

13. – miscellaneous activities.

Further details are presented in Table 1 and can also be found elsewhere in this volume (Chapters 14, 16, 19).

Introduction

The amazing variety of incense, perfumes and other aromatic materials gained our interest and attention when we collected spices in the marketplaces of Addis Ababa and its surroundings.

Aside from incense and myrrh very little is generally found in research literature about the use of plants as perfumes and aromatics in Ethiopia. In this paper those plants and plant products will be treated, which were found in markets in central Shewa, the administrative region around Addis Ababa and in the capital itself. Some plant products have also been reported from the Bale administrative region.

The subject will be treated in three sections: the first will deal with incense and myrrh and will consider their importance in international trade since ancient times. The other two sections will cover aromatic plant materials of different uses and perfume plants, respectively.

Incense and myrrh

From time immemorial the fragrant smoke of burning resins and the aromatic odours of ointments and balms have been used by Man in religious rituals.

In the ancient Mediterranean civilizations incense (or frankincense, as it is also called) and myrrh were considered, at times to be more precious than gold (Gauckler, 1970). The importance of incense in those days is documented by the fact that the first great trade route in history is called the ‘incense road’, covering a distance of about 5000 km from the kingdoms of southern Arabia (‘Arabia Felix’) to the cultural centres to the east of the Mediterranean Sea.

Introduction

Barley (Hordeum vulgare L.), one of the oldest of cultivated plants, has been grown in Ethiopia for at least 5000 years (Harlan, 1969; Doggett, 1970). Generally, Ethiopia is considered as a secondary gene centre, or a centre of diversity, for barley and not as a centre of origin (Tolbert et al., 1979). However, in recent studies some evidence has been presented to suggest that Ethiopia might be a centre of origin (Bekele, 1983b; Negassa, 1985) as was originally suggested by Vavilov. The diversity in Ethiopian barley germplasm accessions has been presented in a number of studies (Ward, 1962; Tolbert et al, 1979; Bekele, 1983a,b; Negassa, 1985) which were based mainly on discrete (non-continuous) characters. In studies on disease resistance in Ethiopian barley it was found that Ethiopian barley germplasm possesses resistance genes for almost all major diseases (Moseman, 1971; Lehmann, Nover & Scholz, 1976). In addition, high protein and lysine contents have been found in some Ethiopian genotypes (Munck, Karlsson & Hagberg, 1971).

In this chapter a detailed analysis is presented of the phenotypic diversity in the barley germplasm collection of the Plant Genetic Resources Centre/Ethiopia (PGRC/E), which possesses considerably more accessions than have been used in earlier diversity analyses. The results of previous studies on Ethiopian barley germplasm will also be summarized, particularly the ones on diversity indices.

Importance of wheat in Ethiopia

Wheat has been and continues to be one of the most important cereal crops in Ethiopia in terms of both area under cultivation and production. In 1983, the area under wheat production was estimated at 625 590 ha with an average production of 1065 kg/ha (Central Statistics Office, 1984). The demand for wheat as a staple food grain is increasing, especially in the urban areas, while its utilization will be high even in the rural sector in the near future. At present, consumer demand for wheat as a staple food grain is increasing, especially in the urban areas, while its utilization will be high even in the rural sector in the near future. At present, consumer demand far exceeds domestic production and wheat imports are costing the country millions of dollars in foreign exchange. Wheat constitutes a large portion of the daily diet of the population and contributes significantly to the calorie and protein intake. It is consumed in several different forms such as leavened bread, pancakes, macaroni and spaghetti, biscuits and pastries. The most common of the Ethiopian recipes are dabo (Ethiopian home-made bread), hambasha (home-made bread from northern Ethiopia), kitta (unleavened bread), injera (thin bread, part of the national dish and prepared mainly from teff), nifro (boiled whole grains, sometimes mixed with pulses), kolo (roasted whole grains), dabo-kollo (ground and seasoned dough, shaped and deep fried) and kinche (crushed kernels, cooked with milk or water and mixed with spiced butter).

Introduction

It will have become evident from the previous chapters in this book that the crop genetic resources of Ethiopia are very diverse and constitute an invaluable base for plant breeding both within and outside the country. Ethiopia is one of the world centres of diversity, identified by N. I. Vavilov some 60 years ago. Not only does it possess important diversity in crops domesticated elsewhere, such as wheat, barley, grain legumes and several oil plants; it also has developed its own indigenous cultigens, such as teff, sorghum, niger seed (noog), ensete, Ethiopian mustard and coffee, many of which are now of great international importance. Ethiopian breeders have taken full advantage of the crop genetic diversity in their own country, combining it with useful genetic characters brought in from other regions.

Clearly, the importance of Ethiopian crop diversity has not gone unnoticed amongst world breeders. Vavilov, who visited Ethiopia in 1927, pointed out the value, particularly to wheat and barley breeders, of the Ethiopian landraces and their extraordinary morphoagronomic variation (Vavilov, 1931).

In this final chapter we shall attempt to summarize the value of Ethiopian crop genetic diversity both nationally and internationally.

Wheat

Ethiopia is unique in containing a very wide diversity of tetraploid wheat, but very little hexaploid wheat diversity; this latter was probably introduced in recent times.

Introduction

Konso is the name of a relatively small area (approximately 500 sqkm) situated in south-west Ethiopia at a latitude of 5°15’ N and a longitude of 37°30'E, which is populated mainly by the Konso people. The topography is characterized by rugged and stony highlands, cut by deep valleys that enter into the heart of the country. The main agricultural area ranges in altitude from 1400 to 2000 m above sea level and the climate is of the dry montane type with temperatures ranging from below 15 °C at night to 32 °C during the day at the hottest time of the year. The Konso Highlands run across the Rift Valley in an east-west direction and are situated in the dry belt of Ethiopia with an unreliable rainfall not exceeding 800 mm per year. There are two rainy seasons: the big rains are concentrated in March and April and the small rains fall around October and November. In general, the rains come in the form of violent thunderstorms which seldom last more than two hours (Hallpike, 1972). The Sagan River forms the eastern and southern borders of Konso, while to the north the great plains of Gomida and Lake Shamo and, more to the west, the Gidole mountains and the Woito Valley form natural boundaries.

The Konso are a small tribe of about 60000 people (Minker, 1986). Their language belongs to the East Cushitic group (Hallpike, 1970).

Introduction

It is generally accepted that Ethiopia is an important domestication and genetic diversification centre of crop species (Purseglove, 1968; Mooney, 1979). Likewise, it is instinctively felt that it must have a rich flora. But this is not known quantitatively, partly because efforts at documenting Ethiopian plants have been sporadic (Friis, 1982) and as a result, many plants remain unrecorded. On the other hand, hasty recording has often meant that a species goes by different names, causing double counting. The situation is made more confusing because the plant specimens collected from Ethiopia are scattered in various herbaria, mostly in Europe. The information published on them is equally scattered and in numerous European languages (Cufodontis, 1953–72). Compiling information on Ethiopian plants is thus a daunting task.

The Ethiopian Flora Project, supported financially by both the Ethiopian Government and the Swedish Agency for Research Cooperation with Developing Countries (SAREC), was launched to meet this challenge. The project is therefore building a reference herbarium and library so that, in some years’ time, information on Ethiopian plants will be found organized at one reference point in Ethiopia. The project is training young Ethiopian taxonomic botanists so that this information can be continually augmented, managed and updated. It is also writing a Flora of Ethiopia, covering the whole country, so that plant identification, both in the field and in the herbarium, becomes possible.

Introduction

Based on the concept of gene centres, developed by N.I. Vavilov in the 1920s, Ethiopia represents one of the eight centres in the world where crop plant diversity is strikingly high and where some of the crops concerned became domesticated. The concepts of centres of origin and diversity have evolved considerably since Vavilov's days as shown for instance by Harlan (1975) and by Hawkes (1983). Nevertheless, some of the basic characteristics which apply to the majority of the world's gene centres generally hold also for Ethiopia though varying from one crop to another. The highly dissected highland of Ethiopia includes natural barriers formed by mountains (up to approximately 5000 m above sea level) or ravines (sometimes more than 1300 m deep) where crop plants would have evolved in isolation under primitive agricultural conditions. To this must be added the ancient and very diverse cultural history of its people, thus providing many thousands of years of artificial selection within the landrace populations since the early days of agriculture. However, several crops which possess an extremely high diversity in Ethiopia do not follow all the basic principles required for a centre of origin in a given crop. In the case of barley, for instance, no wild relatives are known within the country nor is there any archaeological evidence to indicate early cultivation or domestication.

Introduction

Wheat (Triticum spp.) covers 12 per cent of the total area of about 6 million hectares of land, producing approximately 7 million tonnes of food grain, in Ethiopia. Both tetraploid and hexaploid wheats are important in the farming systems; the former takes more than 50 per cent of the share. Comprehensive wheat improvement programmes for durum and bread wheat have been developed to contribute to the overall effort of increasing food grain production in the country.

Diseases are among the major constraints limiting wheat production. The wheat rusts (Puccinia spp.), Septoria diseases and Fusarium spp. are the economically important diseases that therefore require resistance breeding programmes. In particular, with the increase of bread wheat acreage under the management of state farms, the potential danger of yellow rust epidemics (caused by P. striiformis) in Arsi and Bale highlands in southern Ethiopia warrants a well organized breeding programme.

This paper deals with the approaches in breeding for disease resistance with particular emphasis on the use of indigenous and exotic germplasm resources in the bread wheat breeding programme in Ethiopia.

Guiding principles

Considering the complexity of the biotic and abiotic environments of the Ethiopian agro-ecosystems, three guiding scientific principles have been essential in planning and implementing the wheat breeding programme for disease resistance. These are (a) care-ful consideration of the genetic variation phase of the breeding programme; (b) critical analysis of the crop ecosystem; (c) proper evaluation of the pathosystem.

Introduction

In the past, collecting activities have concentrated on particular species or on certain genetic characters which plant breeders were seeking. At present, because of the rapid rate of genetic erosion of crops in most parts of the world, exploration trips are now becoming ‘rescue operations’ in which as much diversity as possible is being collected. The concept of ‘now or never’ is in the forefront of the collectors’ minds.

The methodology of collecting and the scientific basis of sampling have also received considerable attention. Whereas some 30 years ago it was thought sufficient to collect a few seeds from a single plant, write one or two words on a label and put them all into a bag, this method is now thought to be most unsatisfactory.

The genetic resources collector is looking for diversity. Whereas the botanical or horticultural collector was content to collect a few herbarium specimens and a small packet of seeds, to serve as a representative for a species in a particular area, the genetic resources collector needs not uniformity, but diversity. How is this to be accomplished?

Studies of the population genetics of wild species by Allard (1970) and his colleagues showed that more sophisticated methods were needed if a reasonable amount of the genetic diversity of a species was to be captured.

Introduction

Ethiopia is an area rich in germplasm of many plant species and was considered as a primary centre of crop diversity by Vavilov (1951). Among the most important plant genetic resources of the East African region, and indeed of all of Africa, are forages and especially forage grasses (Zeven & Zhukovsky, 1975). Large areas of Africa are covered with tropical savannah with a great diversity of grasses which are vigorous and polymorphic (Clayton, 1983). Tropical forage legumes and browse species are also endemic. In particular, Africa has been described as the centre of diversity of the browse shrubs of the subfamily Caesalpinioideae (Williams, 1983).

The genetic resources of forages are usually found in wild populations since they have only been cultivated on a commercial scale for about 50 years and no landraces are available (Williams, 1983). This is very different from crop species and therefore the collection strategies for forages differ to accommodate the population structures found in the wild. Marshall & Brown (1983) have defined the objective of forage plant exploration as the collection of material with the maximum amount of useful genetic variability within a strictly limited number of samples. The strategy of the International Livestock Centre for Africa (ILCA) is to collect representative population samples from the wild, although in some cases only a few plants can be found growing together as a population and sampling is therefore limited (Lazier, 1984).

Introduction

The Ethiopian Government attaches a high priority to plantation forestry. Through institutions like the State Forests Conservation and Development Department, the Soil Conservation and Community Forestry Development Department and the revolutionary mass organizations, more than 40 000 ha of degraded lands annually are put under some kind of forest-like vegetation cover, partly as pure stands, partly in combination with other land uses such as agriculture or grazing.

This is an effort that requires the introduction of suitable trees, growing from seeds of known origin, if the forests (or agroforests) are to fulfil their objectives: erosion control and production of fodder, fuelwood, construction wood and timber. Tree species suitable for plantation forestry should have a maximum adaptability to a wide spectrum of prevailing (and sometimes rapidly changing) environmental conditions. In order to meet this requirement, the forester must be able to select from natural or planted tree populations, which must have a certain degree of genetic diversity.

Unfortunately, the Ethiopian natural tree populations have been, and still are, subject to indiscriminate destruction. Shifting cultivation and traditional grazing have been practised for centuries in Ethiopia. This, and the relentless cutting for fuel and building needs by a dense and rapidly growing population, have led to an almost complete deforestation of the Ethiopian highlands today.

The remaining forests are very unequally distributed.

Introduction

Genetic conservation has arisen as a solution to some of the problems caused by Man in his social and agricultural relationship with the environment (Simmonds, 1979). Unwise exploitation of nature has caused an irreversible loss of variability and has become the major cause of worldwide genetic erosion. The seriousness and rapid expansion of the problem has created a universal need to collect and conserve genotypes that would no longer be available if not conserved today. This can best be achieved by maintaining a wide range of plant materials covering the maximum variability existing at present.

Taking into account these needs, and being aware of the enormous diversity of crops in Ethiopia, the Plant Genetic Resources Centre (PGRC/E), is currently working on the conservation of both orthodox and recalcitrant crops. At present, the centre holds 40000 accessions of 78 different species, including the germplasm material preserved in field genebanks.

Facilities, personnel and organization of the Conservation Division

The longevity of any conserved material depends upon the system of conservation used and this, in turn, is affected by the facilities existing at any given genebank and the quality of technical knowledge available. The inadequacy of the infrastructures for the maintenance and utilization of plant genetic resources remains the major limiting factor in the establishment of a genebank in a developing country. Storage facilities require large inputs in terms of construction, equipment and maintenance costs, as well as capable technicians and a reliable electricity supply.

Introduction

Ethiopia is the only country that produces teff as a cereal crop. Teff occupies the largest area of cultivated land under cereal production in Ethiopia, and as such it is the most important crop. According to the statistical information of five years' average from 1979–80 to 1983–4, teff was cultivated each year on 1.385 million hectares, followed by barley 0.851, wheat 0.609, maize 0.780 and sorghum 0.994 million hectares. The national average grain yield of these cereals for the same five-year period was 9.1 quintals per hectare (q/ha) for teff, barley 11.83, wheat 11.26, maize 17.35 and sorghum 14.57q/ha (Central Statistics Office, 1984).

Teff is mainly cultivated as a single crop. However, in a few areas it is cultivated under a multiple cropping system. In such cases it is usually grown as an intercrop with Brassica carinata, Carthamus tinctorius or Helianthus annuus. It is also relay cropped with Zea mays and Sorghum bicolor.

Teff is mainly used for making a pancake-like bread called ‘injera’. In some cases it is used to make porridge and native alcoholic drinks called ‘tella’ and ‘katikala’. Its straw is highly valued and is used as feed for cattle. In addition, the straw is incorporated with mud to reinforce it and used for plastering walls of houses.

Teff is on average as nutritious as any of the major cereals.