Diversity among a Heterodera glycines field isolate and derived inbreds based on RAPD analysis and reproduction on soybean genotypes

A field population of Heterodera glycines was inbred by a combination of co ntrolled male-female matings and inoculation of soybean with second-stage j uveniles (J2) from single cysts. The initial and four F-o inbred population s were subjected to random amplified polymorphic DNA analysis and were also tested for their ability to reproduce on race differentials. The RAPD patt erns of the inbred populations had a lower number of total bands and a lowe r percentage of polymorphic bands among individual cysts than the initial p opulation. The estimated number of polymorphic loci detected by RAPD analys is was about 25% for the initial population and 4% to 7% fur the inbred lin es. Reproduction of H. glycines decreased for 6 of 24 inbred-soybean combin ations. In particular, reproduction of three inbred populations on PI 90763 was greatly reduced. Inbreeding did not decrease variance of cyst number o n soybean genotypes. The inbreeding coefficient calculated from RAPD data w as greater than that derived from the known inbreeding pedigree.