“Genetic analysis of greenbug populations from Argentina and Chile based on an enzyme analysis”

COLLADO M., CASTRO A.M. AND A.F.G. DIXON

PESQUISA AGROPECUáRIA BRASILEIRA

Lugar: San Pablo; Año: 2008

0100-204X

A high of enzyme polymorphism was found in twenty-nine Schizaphis graminum (Rondani) population and sixty clones collected from different regions of Argentina and Chile. The enzymatic structure was descripting for the esterase system, founding nine different loci. In addition, the latitudinal trend in this system was determined and populations were assigned to one of three groups. The first group consisted of aphids collected from 26º 50´ SL to 31 40´ south, the second 31º 52´ to 35º 30´ south and the third 37º 08´ to 43º 28´south. Observed heterozygosity was lower than the expected because populations consisted mainly of homozygous individuals. According to the Fsr values the alleles in no group were fixed; group one had a slight heterozygous excess, whereas the others two groups had homozygous excess. According to Frt values the third group had the highest gene flow. There were three populations that could not be assigned to groups.The a-carboxyl-esterase was always present, indicating that the insecticide resistance is wide spread throughout the Argentinean and Chile. There was not relationship between the enzymatic patterns and the biotype, or specie of host plant.