Variation and inter‐relationships of quantitative traits in tef (Eragrostis tef (Zucc.) Trotter) germplasm from western and southern Ethiopia

摘要

Tef, Eragrostis tef (Zucc.) Trotter, is amongst the principal cereals of Ethiopia. Its grain provides about two-thirds of the daily dietary protein intakes of most Ethiopians (Ethiopian Nutrition Survey 1959). With yearly average estimates of 2.11 million hectares and 1.68 million tons (Central Statistical Authority 2000), tef accounts for about 31?% of the total acreage and 22?% of the gross grain production of all the seven major cereals grown in the country. The sustained extensive cultivation of tef by the Ethiopian peasants can presumably be attributed to the broad adaptation of the crop with reasonable tolerance to both high and low moisture stresses, its preference for staple consumption, fodder value of its straw, and high market prices of both the grains and straw (Ketema 1993; Assefa et al. 1999).In spite of its supreme importance in the Ethiopian agriculture, the productivity of tef is very low. The national average grain yield is about 0.8 t/ha (Central Statistical Authority 2000). On the other hand, Ethiopia is the center of both origin and diversity of tef (Vavilov 1951), and the cultivation of the species for human consumption of the grains has hitherto been little known elsewhere in the world. This, therefore, implies that the primary source of variability for the genetic improvement of the crop rests primarily upon the indigenous germplasm resources available in the country.Field evaluation of 125 single panicle collections taken from Ethiopia in USA showed considerable diversity in most of the characters assessed (Mengesha et al. 1965). Upon studying collections from different parts of Ethiopia, Ebba (1975) identified and described 35 distinct tef cultivars based mainly on plant vigor, phenology, pigmentation of floral bracts, and kernel coat color. Other subsequent studies (Tefera et al. 1990; Bekele 1996; Assefa et al. 1999, 2000, 2001a,b) revealed considerable diversity of the germplasm in many of the traits studied.Recently, there has been renewed initiatives in the acquisition, conservation and utilization of tef genetic resources. As part of these efforts, 60 tef germplasm populations each represented by 50 random panicle samples from farmers’ fields were collected from six regions in the western and southern parts of the country in the 1998/99 main season. The total of 3000 single panicle-derived lines were evaluated on pellic Vertisols at Debre Zeit Agricultural Research Center during the 1999/2000 main season. The objectives were to assess the extent and pattern of variation of the germplasm and to study the inter-relationships of 17 quantitative pheno-morphic and agronomic traits with respect to regions and altitude zones of origin.