VARIATION AND INTERRELATIONSHIPS OF AGRONOMIC TRAITS IN ETHIOPIAN TETRAPLOID WHEAT LANDRACES

Sixty tetraploid wheat (Triticum turgidum L.) landrace agrotypes colle cted from the central highlands of Ethiopia and one commercial check c ultivar (Boohai) were evaluated at Akaki experimental station for grai n yield and 11 other component traits. The objectives were to estimate phenotypic (PCV) and genetic (GCV) coefficients of variation, broad-s ense heritability (H) and genetic advance (GA), and to determine the i nterrelationships among the various traits. Genotypic differences amon g the agrotypes were highly significant for all the traits considered. Compared to Boohai, the landrace agrotypes were later in days-to-head ing (DTH) and maturity (DTM), and had shorter grain filling period (GF P), lower fertility (KS) and lower 1000-kernel weight (TKW). By contra st, they were superior to Boohai in tiller number (TN), biological yie ld (BY) and grain yield plant(-1) (GYP). Intermediate to high order es timate combinations of GCV, H and GA (as % of the mean) were observed for TN, GYP, number of kernels spike(-1) (NKS), harvest index (HI) and TKW. GYP showed a moderate heritability which was higher than GFP, BY and Plant height (PHt). DTH and DTM were strongly correlated, but bot h were negatively associated with the rest of the traits except PHt. T he negative correlation of DTM with GYP was largely indirect via other characters. PHt had either a weak or negative association with the ot her traits. TN and TKW were positively correlated with GYP, and had hi gh and intermediate direct effects, respectively. These two traits, ho wever, were negatively correlated and showed a substantial counter-bal ance effect via one another. It appears that, for the short-term, impr ovement of the Ethiopian wheat landraces may be possible through indir ect selection for TN and TKW or direct selection for grain yield per s e. In the long-run, crossing programmes between indigenous and introdu ced germplasm may be necessary.