There has been a growing interest for the analysis of genetic diversity of species Conyza bonariensis, C. canadensis and C. sumatrensis, popularly known as horseweed or motorboat, which in recent years have caused losses in several crops, mainly soybean, in Brazil and worldwide. The purpose of this study was to estimate the genetic samples of C. sumatrensis from northwestern state of Paraná. Isozyme analysis in the tissue of C..sumatrensis leaves was performed to estimate the genetic variability within populations and among different populations to recommend a uniform or differential treatment for the control of these weeds in that region. Four enzymatic systems (ACP, GPI, MDH and PGM) were analyzed and 10 loci with 10 alleles detected, showing no genetic diversity within and between the populations analyzed, as shown by the presence of only homozygotes. The enzymes examined in this study indicated that the plants from the three regions are genetically uniform and that the uniformity observed for these genetic loci is a previous indication that equivalent doses of glyphosate can be applied to control the growth of these biotypes.
isozymes; polymorphism; fleabane; Conyza; genetic diversity
