Caryo-phenotype relationships in Ditylenchus dipsaci

Abstract

The relationship between polyploidy and body size in Ditylenchus dipsaci (Kuehn) Filipjev was studied by Sturhan (1970) who found that German populations of the nematode had a chromosome number 2n = 24, but populations originated from Vicia faha and Plantago maritima, which had a longer body size, had also a chromosome number 2n = 54. He postulated that these larger sized populations could belong to the giant race of D. dipsaci reported from Algeria by Debray and Maupas (1896). The basic aploid number of 12 was confirmed for populations from southern Italy (Grimaldi De Zio et al., 1975). However, studying chromosome number of populations of D. dipsaci from various geographical origins it was noticed that different caryotypes occurred within this species (Grimaldi De Zio et ai., 1980). Aim of this study was to determine chromosome numbers in various populations of D. dipsaci to investigate any possible influence of the caryotype on the phenotype, and to observe when the biometrics could be affected by some factors such as sex, host and geographical origin.