by Seyfu Ketema

Center of origin and diversity

The fact that several endemic and nonendemic species of Eragrostis, some of which are considered the wild relatives of tef, are found in Ethiopia and, in addition, the fact that the genetic diversity for tef exists nowhere in the world except in Ethiopia, indicates that tef originated and was domesticated in Ethiopia. Vavilov identified Ethiopia as the centre of origin and diversity of tef. As with several other crops, the exact date and location for the domestication of tef is unknown. However, there is no doubt that it is a very ancient crop in Ethiopia, where domestication took place before the birth of Christ.

On the basis of linguistic, historic, geographic and botanical notes, tef is assumed to have originated in northeastern Africa. The current area of cultivation is probably not the initial one of domestication; domestication probably occurred in the western area of Ethiopia, where agriculture is precarious and semi-nomadic.

Geographic distribution

Most of the Ethiopian farmers use traditional landraces of tef and these are distributed all over the country. Local cultivars such as Gea­Lamie, Dabi, Shewa­Gimira, Beten and Bunign, which are early maturing varieties (<85 days), are widely used in areas that have a short growing period due to low moisture stress or low temperature. The same varieties are also used in areas with adequate rainfall and where double cropping is practiced. In the highly productive and major tef­producing regions of Gojam and Shewa, and in other regions where environmental stress is not severe, the local cultivars such as Alba, Ada and Enatit are used. Modern varieties are used in many regions but in very small areas within each region. In the regions of Gojam and Shewa, which are located in the central highlands of Ethiopia and are also the largest and major tef production areas in the country, modern varieties are used as well as traditional landraces and local cultivars.

Properties

The composition of tef is similar to that of millet, although it contains generally higher amounts of the essential amino acids. The amino acid composition of tef is excellent, its lysine content is higher than that of all cereals except rice and oats, it has good mineral content and its straw is nutritious.

Uses

In Ethiopia, tef is traditionally grown as a cereal crop. The grain is ground to a flour which is mainly used for making a popular pancake -- like the local bread called enjera -- and sometimes for making porridge. The grain is also used to make local alcoholic drinks, called tela and katikala. Tef straw, besides being the most appreciated feed for cattle, is also used to reinforce mud and plaster the walls of tukuls and local grain storage facilities called gotera. Tef grain, owing to its high mineral content, has started to be used in mixtures with soybean, chickpea and other grains in the baby food industry.

Enjera made from tef is traditionally consumed with wot, a sauce made of meat or ground pulses like lentil, faba bean, field pea, broad bean and chickpea. The traditional way of consuming tef with wot provides a well balanced diet.

Conservation

The Plant Genetic Resources Centre of Ethiopia (PGRC/E), now called the Biodiversity Institute, is actively engaged in collecting, conservation and characterization. Utilization of the germplasm for the tef improvement program is mainly done in cooperation with the Institute of Agricultural Research. Currently the PGRC/E has a total of 3842 accessions of tef out of which 187 accessions are repatriations, 357 selections, 1310 accessions collected by other institutes and 1988 accessions collected by the PGRC/E.

Breeding activities

Applied breeding work to improve tef included direct selection from the landraces and intraspecific hybridization, while at the basic research level, investigations were made in the area of biotechnology. The applied research attempts in the areas of mutation and interspecific hybridization programs have not yet contributed to the development of improved cultivars.

On the other hand, the direct selection from the landraces and the intraspecific hybridization program which was employed to effect gene recombination were successful in developing several improved cultivars of tef with desired traits. The improved cultivars developed include: cultivars that have high grain yield with wide or specific adaptation, cultivars with acceptable high grain quality, and early maturing, high-yielding varieties. All the improved cultivars were accepted by farmers and currently are in production. Direct selection from the landraces, mutation breeding and intraspecific hybridization were tried for developing lodging­resistant varieties. However, so far no success has been achieved.

Lodging is still one of the production constraints and therefore the breeding program has the development of lodging-resistant varieties as one of its objectives. Other production constraints are: low-yielding cultivars, low moisture stress resistance, waterlogging, frost, weeds, poor soil fertility, diseases and insects. Generally, the tef crop improvement program attempts to solve these production constraints through a multidisciplinary research approach. Specifically, the breeding program should overcome the problems of low grain yield, and also develop cultivars that are resistant to low moisture, waterlogging and disease as there is a wealth of genetic diversity within tef germplasm.

Ecology

Tef is adapted to a wide range of environments and is presently cultivated under diverse agroclimatic conditions. It can be grown from sea level up to 2800 m asl, under various rainfall, temperature and soil regimes. However, according to experience gained so far from national yield trials, conducted at different locations across the country, tef performs excellently at an altitude of 1800­2100 m, annual rainfall of 750­850 mm, growing season rainfall of 450­550 mm and a temperature range of 10°C­27°C. A very good result can also be obtained at an altitude range of 1700­2200 m and growing­season rainfall of 300 mm.

Agronomy

In Ethiopia, tef is cultivated in much the same way as wheat and barley. Depending on the location and maturity period of the cultivar, it is grown during the main growing season between July and November, and also during the small rainy season between March and June. It is mainly cultivated as a monocrop, but occasionally under a multiple cropping system.

Limitations of the crop

The small size of tef seed poses problems during sowing, and indirectly during weeding and threshing. At sowing, the very small seed size makes it difficult to control population density and its distribution. This remains true whether one broadcasts the seed by hand, uses a broadcaster or a seed driller.

The uneven plant stand after germination has an impact on nutrient use, efficiency of the crop and crop yield. Owing to the scattered plant stand, farmers find it difficult to use mechanical weeding implements and are forced to either hand-weed or to use chemical herbicides.

Landraces and current cultivars give low yield. At present the national average grain yield of tef is 910 kg/ha. Improved varieties of tef give a grain yield of 1700-2200 kg/ha on farmers' fields and 2200-2800 kg/ha on research­managed large farms. However, no comprehensive study has been conducted to assess the yield potential of the crop.

Prospects and research needs

Ethiopian farmers prefer to grow tef because of the following advantages:

• It can be grown in areas experiencing moisture stress.

• It can be grown in waterlogged areas and withstands anaerobic conditions better than many other cereals, including maize, wheat and sorghum.

• It is suitable for use in multiple­cropping systems such as double, relay and intercropping.

• Its straw is a valuable feed during the dry season when there is an acute shortage. It is highly preferred by cattle over the straw of other cereals and demands high prices in the markets.

• It has acceptance in the national diet, has high demand and high market value and hence enables farmers to earn more than with other crops.

• It is a reliable and low­risk crop.

• In moisture­stress areas, farmers use it as a rescue crop. For example, around Kobo and Zeway, which are areas with low and erratic rainfall, farmers first plant maize around April. If this fails after a month or more because of moisture stress or pest problems they plough it under and plant sorghum. If this also fails after a month or more then they sow tef as a last resort, which often survives on the remaining moisture in the soil and yields some grain for human consumption and straw for feed.

• It is not attacked by weevils and other storage pests and therefore is easily and safely stored under local storage conditions. This results in reduced post­harvest management costs.

• Compared with any other cereals growing in Ethiopia it has fewer disease and pest problems.

Seyfu Ketema, Biodiversity Institute, Addis Abeba, Ethiopia