Evaluation of Tef [Eragrostis tef (Zucc.)Trotter] Genetic Diversity Using Morphological Characters and Microsatellite Markers

Abstract

Tef (Eragrostis tef) is a cereal crop of great cultural and economic importance in Ethiopia. Even though Ethiopia is the center of origin and diversity; exploiting the genetic potential of the crop has been a challenge because of the limited information available regarding the diversity state of the germplasm accessions in the Gene Bank. Assessment of the genetic diversity of these accessions using morphological and molecular markers is one of the primary tasks in tef breeding. Enhancing its breeding using markers requires a systematic and continuous evaluation of the genetic diversity of the crop species. Therefore, this study was conducted to assess the genetic diversity of tef accessions obtained from the Gene Bank using 12 morphological and 10 SSR markers. Sixty four tef accessions were planted in completely randomized design at DZARC during the 2019 cropping season. Analysis of variance for quantitative traits showed significant variation (P < 0.05) among the tested accessions. Cluster analysis of quantitative traits revealed that the accessions were grouped in to eight distinct clusters. The first five principal components explained 62.62% of the total variation. The analysis of molecular variance showed highly significant (P<0.001) variances; 56% and 39% of the total variability could be attributed to differences within and among tef accessions, respectively. Lowest Fst value (0.05) was recorded among the studied tef populations. A total of 914 alleles were detected with an average 14.5 alleles per locus. Polymorphic Information Content (PIC) ranged from 0.06 (CNLTs2) to 0.9 (CNLTS6), with a mean of 0.8 suggesting sufficient discrimination power of the markers to discriminate the tested accessions. The mean value of major allele frequency and number of effective alleles were 0.33 and 3.32 respectively. The mean value of gene flow (Nm) and Shannon’s information index (I) 4.74 was 1.65 respectively. The highest numbers of private alleles (1.0) were recorded from West Gojjam populations. The Nei’s genetic distance value ranged from 0.63 to 0.91.Three major groups were created by cluster analysis by merging accessions from different populations, which may imply the existence of gene flow. The PCoA analysis showed that accessions from different collection sites often clustered together. Therefore, attention should be given for these areas in any improvement and conservation programs. The result from these studies suggests that possibilities for identification of tef accessions superior for yield related traits, indicating the need for the initiation of a planned breeding and conservation programs.