Species identification of cyst and root-knot nematodes from potato by electrophoresis of individual females.

To carry out rapid and reliable species identification of Globodera and Meloidogyne specimens, two electrophoretic methods were modified and adapted for an automated electrophoresis system (PhastSystem, Pharmacia). Proteins of individual Globodera cysts were identified using isoelectric focusing and a sensitive silver stain. Proteins of young single Meloidogyne females were separated using polyacrylamide gradient gels and stained for the isozymes esterase and malate dehydrogenase.

A genetic map of potato (Solanum tuberosum) integrating molecular markers, including transposons, and classical markers.

A genetic map of potato (Solanum tuberosum L.) integrating molecular markers with morphological and isozyme markers was constructed using a backcross population of 67 diploid potato plants. A general method for map construction is described that differs from previous methods employed in potato and other outbreeding plants. First, separate maps for the female and male parents were constructed. The female map contained 132 markers, whereas the male map contained 138 markers. Second, on the basis of the markers in common the two integrated parental maps were combined into one with the computer programme JoinMap. This combined map consisted of 175 molecular markers, 10 morphological markers and 8 isozyme markers. Ninety-two of the molecular markers were derived from DNA sequences flanking either T-DNA inserts in potato or reintegrated maize transposable elements originating from these T-DNA constructs. Clusters of distorted segregation were found on chromosomes 1,2,8 and 11 for the male parent and chromosome 5 for both parents. The total length of the combined map is 1120 cM.