Trait diversity, heritability and genetic advance in selected germplasm lines of tef [Eragrostis tef (Zucc.) Trotter]

Abstract

The genetic improvement of the Ethiopian cereal, tef, Eragrostis tef (Zucc.) Trotter, depends upon the variability in the indigenous germplasm. A bi-replicated randomized complete block field experiment was, therefore, carried out at Debre Zeit and Alem Tena in Ethiopia during the 1996 main season to study the pheno-morphic and agronomic trait diversity in 320 tef germplasm lines. All of the 17 traits assessed showed substantial (p ≤ 0.001) variation among the lines. Genotypes and locations interacted significantly (p ≤ 0.05) on 11 of the traits. At about 50% similarity level, the tef lines grouped into six major clusters of nine to 243 lines. Five principal components (PCs) extracted about 71% of the entire variation of the lines. About 28% of the total variance explained by the first PC was due chiefly to variation in main shoot culm length, diameters of the two basal culm internodes, panicle length and grain yield/panicle. About 16% of the whole variance explained by the second PC originated mainly from variation in the length of the first and second basal culm internodes, grain yield/plant, and peduncle length. The third PC accounting for about 12% of the entire variance resulted largely from variation in harvest index and shoot phytomass yield/plant. Across traits, the phenotypic and genotypic coefficients of variation varied in that order from about 2% for grain yield/panicle to 58% for number of fertile tillers/plant, and from less than 1% for diameters of the two basal culm internodes and grain yield/panicle to 35% for panicle length. Estimates of broad sense heritability and genetic advance (as ratio of the mean) were highest for panicle length (71%) and number of fertile tillers/plant (21%), respectively. But both of these were lowest for the second basal culm internode diameter (< 1%). Overall, the study confirmed that tef is a highly versatile crop with broad trait diversity in the germplasm, and this offers ample opportunities for improvement through breeding.