Genetic erosion and changes in distribution of sorghum (Sorghum bicolor L. (Moench)) landraces in north-eastern Ethiopia

Abstract

Ethiopia is believed to be the centre of origin and domestication for sorghum, where sorghum remains one of the main staple crops. Loss of biodiversity is occurring at an alarming rate in Ethiopia and crops, including sorghum, have long been recognized as vulnerable to genetic erosion. A major collection of sorghum germplasm was made in 1973 by Gebrekidan and Ejeta from north-eastern Ethiopia. A new collection of landraces was made in 2003, and these were field evaluated at Sirinka in 2004 along with representative samples from the 1973 collection. Farmer surveys and soil and climate surveys were also performed. Preliminary analysis demonstrated that some important landraces have disappeared either locally or regionally in the past 30 years and many other landraces have become marginalized. Landraces which are less preferred in terms of agronomic value and end use, and introductions, have become increasingly important. Late maturing landraces were found to be particularly vulnerable, with a number disappearing altogether. Farmers have become more risk averse, and factors such as declining soil fertility, more frequent drought and unreliable rainfall, and increased pest infestation have contributed to a change in farmer landrace selection. Data are presented on the variability and unique characters of some of the Ethiopian landraces, and implications for conservation are discussed.

Geographic patterns of phenotypic diversity in sorghum (Sorghum bicolor (L.) Moench) landraces from North Eastern Ethiopia

“…Consequently, landraces with 50% or more grain covered with glume were not important among the landraces evaluated. This result is in line with previous observation in farmers' fields (Shewayrga et al, 2008). Such landraces were not widely grown and most of them were small seeded (1000-seeds weight) with brown color and often with very loose or open panicle.…”

“…The analyses for quantitative traits revealed wide variability among the landraces. Previous studies (Teshome et al, 1999;Seboka and van Hintum, 2006;Shewayrga et al, 2008) reported that farmers purposely maintain and grow many landraces to address various needs as well as risk aversion strategy, and the landraces vary in maturity, yield potential, stress tolerance, end-use quality and other agronomic traits. Diversity studies in NE Ethiopia have also shown high diversity for other crop landraces including tef (Assefa et al, 2001;Kefyalew et al, 2000), barley (Abebe et al, 2010;Mekonnon et al, 2015) and durum wheat (Eticha et al, 2005;Mengistu et al, 2015).…”

“…The high lysine sorghum lines came from Welo collections (Singh and Axtell, 1973). The majority of sorghum production in the country in general and NE Ethiopia in particular depends on landraces (Gebrekidan, 1973;Worede, 1992;Seboka and van Hintum, 2006;Shewayrga et al, 2008). These landraces are good sources of genepool for sorghum improvement program to develop high yielding and farmer preferred improved varieties.…”

DNA markers reveal genetic structure and localized diversity of Ethiopian sorghum landraces

“…The low to moderate geographic differentiation could be attributed to frequent gene flow among fields as a consequence of seed exchanges among farmers, and/or to restriction of the intensity of genetic drift due to a high effective population size (Dje et al, 1999). Earlier observations (Shewayrga et al, 2008) showed that many landraces with the same local name are grown in two or more zones attributed to the existing farmers' seed system. Seeds are shared through gift, exchange in kind, and purchase.…”

“…The majority of sorghum production in the country in general and NE Ethiopia in particular depends on landraces (Gebrekidan, 1973;Worede, 1992;Teshome et al, 1997Teshome et al, , 1999Seboka and van Hintum, 2006;Shewayrga et al, 2008). The sorghum grain is mainly used for Injera, a fermented flat bread and staple Ethiopian dish.…”