Species Diversity in Wheat Landrace Populations from two Regions of Ethiopia

Abstract

Wheat (Triticum spp.) landrace populations in Ethiopia are mostly species mixtures. However, no quantitative data is available with regard to their species components. We studied here 32 wheat landrace populations originating from two regions (Bale and Wello). A total of 2559 individual plants, 45-110 plants representing each population, were classified into their species components. Five tetraploid (2n ¼ 4x ¼ 28) and one hexaploid (2n ¼ 6x ¼ 42) wheat species were found in mixtures of varying proportions. These included the tetraploids Triticum durum Desf., Triticum turgidum L., Triticum aethiopicum Jakubz., Triticum polonicum L., Triticum dicoccon Schrank and the hexaploid Triticum aestivum L. Also found, however in a rare frequency, in two populations from Wollo was T. durum Desf. convar. durocompactoides Flaksb. (Triticum pyramidale Percival), which is a very dense spiked durum. Discriminant analysis using seven qualitative traits revealed 91.5% correct classification of the wheat species, beak awn and awn length with the most significant importance. Single species were found in eight of the populations; six were for T. durum and two for T. aethiopicum. Two to three species-combinations were the most frequent; a maximum of four species was recorded in one population. The highest diversity index (H¢) observed was 0.44. T. durum was the most predominant species. The hexaploid T. aestivum was found in nine of the Wollo populations and, in one population, its frequency reached up to 35.5%. On altitudinal basis, no clear trend of clinal variation was observed both from the frequency distributions and H¢ estimates. The results confirmed that Ethiopian wheats, despite the morphological overlaps, could be classified into their species components with high degree of certainty. For the future, therefore, genetic diversity estimations should be dissolved into their species components for more expeditious utilization and conservation of this important genetic resource.

On-Farm Diversity and Genetic Erosion of Tetraploid Wheat Landraces in Ambo and Dandi Districts, West Shewa, Ethiopia

“…Tesemma et al (1993) stated that Ethiopian wheat landraces are usually mixtures of different agro-types having wider gene pools within one population that can buffer the change of climatic and edaphic factors. Eticha et al (2006) also reported mixtures of five tetraploid wheat landraces and hexaploid wheat in varying proportions in one population of germplams collected from Bale and Welo regions. The species mixtures/agro-types might have an advantage for the farmers when grown in the same field: to add variety to the diet and, on the other hand, to carry diverse genes for disease and pest resistances and adaptability to changing climatic factors (Bekele, 1984).…”

An Evaluation of the Variation in the Morphometric Parameters of Grain of Six Triticum Species with the Use of Digital Image Analysis

“…The evaluated lines of Polish wheat were characterized by high RSD values of most shape and color descriptors. High intraspecies variation can be attributed to the low commercial interest in this species; therefore, conscious efforts to narrow down the gene pool of Polish wheat were not made throughout the centuries [53]. A comparison of the variations in the lines of the analyzed wheat species suggests that rarely farmed ancient species are characterized by a larger gene pool and consequently, greater variations in phenotypic traits [54].…”

Cultivated emmer wheat (Triticum dicoccon Schrank), an old crop with promising future: a review

“…Emmer wheat is cultivated in marginal lands in almost all regions of the country (Gonder, Gojam, Welo, Tigray, Shewa, Bale, Arsi, Hararge, Sidamo and Gamu Gofa), in altitudinal ranges of 1,800-3,000 m (Institute of Biodiversity Conservation of Ethiopia, unpublished). It is one of the major cereal crops in the Bale zone of south eastern Ethiopia (Demissie and Hailegiorgis 1985) and is consciously grown in mixtures with other tetraploid wheats and bread wheat by farmers from Bale and Welo (Eticha et al 2006). This practice allows gene flows between wheat species, reduces the risk of breakdown due to diseases or other stresses, and increases the nutritional value of the production (Bekele 1984; Worede 1997).…”