Genetic and Morpho-phenological Analysis of Redroot Pigweed (Amaranthus retroflexus L.) Populations from Jordan

Experiments were conducted to characterize the diversity of redroot pigweed populations collected from three sites in Jordan by evaluating morpho-phenological traits and by using amplified fragment length polymorphism (AFLP) analysis. Morpho-phenological evaluations conducted outdoors indicated that populations had similar phenological and morphological traits. The three populations had considerably similar diversity. However; one population was less diverse than the other two. Cluster analysis (Ward method) performed on all recorded morpho-phenological traits did not provide evidence of the presence of distinct biotypes in Jordanian redroot pigweed populations. AFLP electropherograms also were unable to define separate biotypes among the three populations. Apparently, the selection pressure imposed by herbicide applications on redroot pigweed populations is not extensive to create distinct biotypes.