Genetic diversity of Soybean Cyst Nematode (Heterodera glycines) populations in Southeastern Goiás state, Brasil

Heterodera glycines, also known as Soybean Cyst Nematode (SCN), is one of the phytosanitary issues that prevents high soybean yields (Glycine max) due to its dissemination capacity and high physiological race variability. The first step towards the proper and safe use of resistant cultivars lies on correctly identifying the physiological race of this nematode in the crop in order to avoid new breed-selection pressure. Thus, the aim of the present study was to genetically characterize the races of Heterodera glycines populations from soybean-producer counties belonging to the Railroad (Estrada de Ferro) Region (Goiás State, Brazil), as well as to investigate their molecular characterization based on RAPD markers. RAPD data were evaluated in a binary way, in which values (1) and (0) were attributed to the presence and absence of amplified bands for each primer, respectively. The binary matrix was used to estimate the genetic distance between populations, based on the Jaccard dissimilarity index. The clustering analysis was carried out based on the calculated genetic dissimilarity matrix, according to Ward’s method. Eight (8) different physiological Heterodera glycines races were found in the investigated counties. Only 10 out of 28 RAPD primers were polymorphic among SCN populations, whereas the remaining primers either did not amplify, or presented low amplification of the DNA fragment. Five genetically-different groups were recorded among H. glycines population accessions, which presented high genetic variability rate.