«Eragrostis tef(Zucc.) Trotter Seyfu Ketema Biodiversity Institute Addis Abeba, Ethiopia 2 Tef. Eragrostis tef (Zucc.) Trotter The International Plant ...»
Promoting the conservation and use of underutilized and neglected crops. 12.
Eragrostis tef(Zucc.) Trotter
Addis Abeba, Ethiopia
2 Tef. Eragrostis tef (Zucc.) Trotter
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Seyfu Ketema. 1997. Tef. Eragrostis tef (Zucc.) Trotter. Promoting the conservation and use of underutilized and neglected crops. 12. Institute of Plant Genetics and Crop Plant Research, Gatersleben/International Plant Genetic Resources Institute, Rome, Italy ISBN 92-9043-304-3
Foreword Humanity relies on a diverse range of cultivated species; at least 6000 such species are used for a variety of purposes. It is often stated that only a few staple crops produce the majority of the food supply. This might be correct but the important contribution of many minor species should not be underestimated. Agricultural research has traditionally focused on these staples, while relatively little attention has been given to minor (or underutilized or neglected) crops,, particularly by scientists in developed countries. Such crops have, therefore, generally failed to attract significant research funding. Unlike most staples, many of these neglected species are adapted to various marginal growing conditions such as those of the Andean and Himalayan highlands, arid areas, salt-affected soils, etc. Furthermore, many crops considered neglected at a global level are staples at a national or regional level (e.g. tef, fonio, Andean roots and tubers, etc.), contribute considerably to food supply in certain periods (e.g. indigenous fruit trees) or are important for a nutritionally well-balanced diet (e.g. indigenous vegetables). The limited information available on many important and frequently basic aspects of neglected and underutilized crops hinders their development and their sustainable conservation. One major factor hampering this development is that the information available on germplasm is scattered and not readily accessible, i.e. only found in ‘grey literature’ or written in little-known languages. Moreover, existing knowledge on the genetic potential of neglected crops is limited. This has resulted, frequently, in uncoordinated research efforts for most neglected crops, as well as in inefficient approaches to the conservation of these genetic resources.
This series of monographs intends to draw attention to a number of species which have been neglected in a varying degree by researchers or have been underutilized economically It is hoped that the information compiled will contribute to: (1) identifying constraints in and possible solutions to the use of the crops, (2) identifying possible untapped genetic diversity for breeding and crop improvement programmes and (3) detecting existing gaps in available conservation and use approaches. This series intends to contribute to improvement of the potential value of these crops through increased use of the available genetic diversity In addition, it is hoped that the monographs in the series will form a valuable reference source for all those scientists involved in conservation, research, improvement and promotion of these crops.
This series is the result of a joint project between the International Plant Genetic Resources Institute (IPGRI) and the Institute of Plant Genetics and Crop Plant Research (IPK). Financial support provided by the Federal Ministry of Economic Cooperation and Development (BMZ) of Germany through the German Agency for Technical Cooperation (GTZ) is duly acknowledged.
Dr Joachim Heller, Institute of Plant Genetics and Crop Plant Research (IPK) Dr Jan Engels, International Plant Genetic Resources Institute (IPGRI) Prof. Dr Karl Hammer, Institute of Plant Genetics and Crop Plant Research (IPK) Promoting the conservation and use of underutilized and neglected crops. 12. 5 Acknowledgements The cooperation and support I received from friends and colleagues were very vital in producing this monograph. I am deeply grateful to all of them and acknowledge their contribution. I would like to express my thanks to Dr Joachim Heller first of all for initiating this work and subsequently for sacrificing his time to personally review and comment on the monograph as well as for arranging for Drs Geoffrey Chapman, Jan Engels and Melak Hail Mengesha to review it. I acknowledge that his comments and those made by the other reviewers were very valuable and have greatly contributed to improving both the content and quality of the monograph. I am grateful to Dr Tadesse Gebremedhin, General Manager and Dr Getinet Gebeyehu, Deputy General Manager of the Institute of Agricultural Research for allowing the work while I was staff of the Institute. I thank Dr Hirut Kebede, Dr Mehari Zewdie, Likyelesh Gugsa, Dawit Tadesse, Tesfaye Mengistu and Zerihun Tadele for providing me with useful information. My thanks also go to MS Linda Sears who had the final and difficult job of editing this work into its present form, and to Abebe Kirub for technical editing of the work and Kidanemariam Hagos for drawing the maps.
Seyfu Ketema Addis Abeba, Ethiopia 4 October 1996
Introduction For sustainable and stable food production, maintaining genetic diversity within and between crop types is increasingly being realized as the most appropriate and indispensable action. This is further emphasized by unpredictable human food needs, changes in taste, technological demand, and the biotic and abiotic production constraints that change with the environments.
Identifying, maintaining and using crop types that can grow under various stress and limiting conditions is essential. It is in this context that tef (Eragrostis tef (Zucc.) Trotter), a traditional crop that grows very well under various stress conditions and is extensively used in Ethiopia, but little known elsewhere, is the subject of this monograph.
Tef is an important cereal crop in Ethiopia. The area under tef cultivation is over one million hectares of land each year. During the 1994/95 cropping season tef occupied 32% of the cultivated land under cereals, while maize occupied 19%, sorghum 16%, barley 15%, wheat 13%, millet 4% and oats 1% (CSA 1995); this is similar to previous production years and clearly shows the importance of tef in Ethiopia.
Outside Ethiopia there is a growing interest in using tef. For example, smallscale commercial production of tef has begun in a few areas of the wheat belts of the USA, Canada and Australia. Tef has been introduced to South Africa and cultivated as a forage crop, and in recent years cultivated as a cereal crop in northern Kenya.
Promoting the conservation and use of underutilized and neglected crops. 12. 7 1 Names of the species and taxonomy Tef (Eragrostis tef (Zucc.) Trotter) belongs to the family Poaceae, subfamily Eragrostoideae, tribe Eragrosteae and genus Eragrostis. The genus contains about 300 species (Costanza 1974).
Accepted synonyms of Eragrostis tef (Zucc.) Trotter, Bull. Soc. Bot. Ital. 1918 no.
4 (1919) 62, are presented below (Costanza 1974):
E. pilosa (L.) P. Beauv. var. tef (Zucc.) Fiori, Nuov. Fl. Anal. Ital. 1: 123.1923;
E. pilosa (L.) P. Beauv. subsp. abyssinica (Jacq.) Aschers et Graebn., Syn. Mitteleur.
Fl. 2(1): 374.1900;
E. abyssinica (Jacq.) Link, Hort. Berol. 1:192.1827;
Cynodon abyssinicus (Jacq.) Rasp., Ann. Sci. Nat. 5:302.1825;
Poa cerealis Salisb., Prodr. Stirp. 20.1796;
P. abyssinica Jacquin, Misc. Austr. 2:364.1781;
P. tef Zuccagni, Diss. Istoria di una piante panizabile. 1775.
The common vernacular name of the crop in Ethiopia is tef. It is also known by the vernacular names tafi in Oromigna and taf in Tigrigna.
According to Ponti (1978), “several wild species of Eragrostis are used in Africa today for food and other purposes. In West Africa, Dalziel(l937) notes the use of E. cilianensis, E. pilosa, E. gangetica, E. ciliaris and E. tremula as cereals, the first species regularly and the others in time of scarcity Gast et al. (1972) describe the importance of E. pilosa to nomads of the Central Sahara: these people harvest grains from plants growing on ants’ nests, and they even pillage the ants’ grain reserves within the nests. E. pilosa grains have apparently been harvested by tribes of the Eastern Sahara since the 12th century AD (Haudricourt 1941). Many species of Eragrostis, then, are obviously attractive food plants: they produce abundant seeds; they are freethreshing; and, above all, they are weeds, inhabiting land disturbed by human activity. The transition from gathering seeds of a selection of readily available weeds to encouraging and cultivating them seems an easy and logical process.” During drought years when food scarcity prevails, tefe tafo (Eragrostis tenella) is collected and used for food in Ethiopia. According to Costanza (1974); Streetman (1963) stated: “Species of Eragrostis were first introduced into the United States in the early 1930s and several of these have been used extensively for reseeding the arid and semi-arid range lands of the southwest. The species of particular interest are E. chloromelas Steud., E. curvula (Schrad.) Nees, E. lehmanniana Nees and E. superba Peyr. Most of the lovegrasses are prolific seed producers, a characteristic almost indispensable for successful range revegetation. Their ability to green up earlier in the spring and remain green in the fall later than the common native grasses also enhances their usefulness.” 8 Tef. Eragrostis tef (Zucc.) Trotter Fig. 1. Eragrostis tef (Zucc.) Trotter. (a) Inflorescence, (b) branch of panicle with floret. (drawing: R. Kilian in Schultze-Motel 1986, reprinted with permission of the Gustav Fischer Verlag, Jena).
Promoting the conservation and use of underutilized and neglected crops. 12. 9 2 Brief description of the crop Tef is a C4, self-pollinated, chasmogamous annual cereal. It has a fibrous root system with mostly erect stems, although some cultivars are bending or elbowing types.
The sheaths of tef are smooth, glabrous, open and distinctly shorter than the internodes. Its ligule is very short and ciliated while its lamina is slender, narrow and nearly linear with elongated acute tips. It has a panicle type of inflorescence showing different forms – from loose to compact, the latter appearing like a spike (Figs. 1 and 2). Its spikelets have 2-12 florets. Each floret has a lemma, palea, three stamens, an ovary and mostly two, in exceptional cases three, feathery stigmas. The caryopsis is 0.9-1.7 mm in length, and 0.7-1.0 mm in diameter, which is very small, and its colour varies from white to dark brown (Tadesse 1975).
Tef is an allotetraploid plant with a chromosome number of 2n =40 and the basic chromosome number of the genus Eragrostis is x =10 (Tavassoli 1986). This is based on a genetic study that resulted in disomic inheritance patterns for different characters of tef (Tareke 1981) and supporting cytological evidence that showed regularity of meiosis in both the pure lines and the intraspecific hybrids which formed 20 bivalents in metaphase I (Tavassoli 1986). In a karyotype study made on 15 Eragrostis spp. it was shown that the chromosomes of tef are very small even by the standards of the genus. When two accessions of tef were observed, measurements of the largest chromosome were 1.6-2.9 µm and of the smallest were 0.8-1.1 µm. The range within each measurement was attributed to differences in condensation (Tavassoli 1986).
Fig. 2. Types of panicles(very loose, loose, semi-loose, semi-compact, compact).