WILD EMMER WHEAT IN JORDAN: I. ECOTYPES AND PHENOTYPIC VARIATION

ABSTRACT

Univariate and multivariate analyses and numerical taxonomy procedures were utilized on the standardized mean values of 17 quantitative traits in the base collection of wild emmer wheat, Triticum dicoccoides Korn., from Jordan, in an effort to identify ecotypes by trait measurements. Five ecotypes were identified on the basis of morphological, developmental, and productive traits. The five ecotypes exhibited different adaptive trait complexes as revealed by principal component and pairwise correlation analyses. It is postulated that particular environmental conditions across the distributional ranges of the species in Jordan resulted in the evolution of adaptive gene complexes which are conserved by genetic linkage or natural selection. The five ecotypes represented the marginal, peripheral, and central distributional range of the species in the country. Two extreme and three intermediate ecotypes were recognized. The extreme ecotypes represent the “grassy” and “robust” types recognized earlier. The three intermediate ecotypes differed markedly from the former two and from each other. They exhibited different patterns of trait associations. A gradual increase in Euclidean distances among these ecotypes was observed as their collection sites moved from marginal to peripheral, and then to central regions of the species' distributional range in Jordan.