PCR zum halbquantitativen Nachweis von Rübenzystennematoden

Increased crop yield of nematode resistant sugar beet varieties compared to non-resistant varieties is dependent upon density of the sugar beet nematode, Heterodera schachtii, being below a certain threshold level. Therefore there is a requirement for an inexpensive quantitative laboratory test for H. schachtii. Currently the standard method to determine nematode densities relies on extraction of cysts from soil samples and their subsequent enumeration which is time-consuming. The method described in this article involves the extraction of nematodes obtained by a technique inducing the hatching of juveniles. Hatching of larvae is induced by incubation of the soil sample with “Acetox” followed by a Baermann funnel extraction. Instead of a visual estimation of nematode densities using a microscope, H. schachtii larvae are identified by a molecular diagnostic. The aim of this study is to distinguish between the three threshold infestation levels by comparing the intensities of PCR products derived from samples containing known numbers of target H. schachtii.