GENETIC VARIABILITY AND ASSOCIATIONS AMONG YIELD AND YIELD RELATED TRAITS OF TEF [ERAGROSTIS TEF (ZUCC.) ROTTER] GENOTYPES IN CENTRAL ETHIOPIA

Tef is one of the most important crops widely cultivated throughout Ethiopia as a staple cereal crop. Assessment of genetic variability in crop species is one of the major activities of plant breeding which helps to design breeding methods to meet the diversified goals. Therefore, a field experiment was conducted to estimate genetic variability, associations of traits, and to determine the direct and indirect effects of yield components on grain yield of tef. The experiment was laid out in 7x7 simple lattice design at two locations (Bishoftu and Akaki) in central Ethiopia during the 2021/22 main cropping season. Analysis of variance for individual locations revealed highly significant (P≤ 0.01) and significant (P≤ 0.05) differences among the genotypes at Bishoftu and Akaki, respectively. The combined analysis of variance over locations also showed significant difference between locations and among genotypes for most of the traits. The genotype x location interaction effect was significant for grain filling period, number of spikelets per panicle, number of florets per spikelets, number of total tillers per plant, lodging index, above ground biomass, grain yield and harvest index. Phenotypic coefficients of variation (PCV) ranged from 3.62% for days to physiological maturity to 18.42% for number of primary panicle branches per main shoot, while the genotypic coefficient of variation (GCV) ranged from 2.96% for day to physiological maturity to 15.82% for number of primary panicle branches per main shoot. Broad sense heritability and genetic advance as percent of mean ranged from 14% (number of total tillers per plant) to 88.67% (day to heading) and 2.43% (number of total tillers per plant) to 28.03% (number of primary panicle branches per main shoot), respectively. High heritability coupled with high genetic advance as percentage of mean was recorded for number of spikelets per panicle, number of primary panicle branches per main shoot and panicle length. The highest positive direct effect was exerted by number of primary panicle branches per main shoot, above-ground biomass and harvest index on grain yield at both genotypic and phenotypic levels. The path coefficient analyses revealed that, the dominant component traits determining grain yield are number of spikelets per panicle, number of florets per spikelet, above-ground biomass and harvest index. Cluster analysis based on Unweighted Pair Group Method with Arithmetic Means (UPGMA) from Euclidean distances matrix resulted in five clusters of the 49 tef genotypes. Principal components analysis revealed that four principal components with Eigen-values greater than unity accounted for 75% of the variation in tef genotypes. Generally, the variation observed among the tested genotypes confirmed the possibility of improving tef genotypes for better yield through selection and hybridization.