Morphological and molecular studies were conducted to characterize the specific identity of 36 isolates of potato cyst nematodes (PCNs) recovered from soil samples collected in several potato producing areas of Algeria. Morphometric data revealed that 44% of isolates contained Globodera pallida alone, 28% contained Globodera rostochiensis alone and 28% mixtures of the two species. Morphometric values of cysts and second-stage juveniles were generally distributed with slight differences in the expected ranges for both Globodera species. Inter- and intraspecific morphometric variability in nematode isolates was noted. Molecular analysis using conventional multiplex PCR with species-specific primers and TaqMan real-time PCR confirmed the morphological identification. In addition, the distribution of both potato cyst nematode species throughout various parts of the country was investigated. In the central areas, the isolates of G. pallida alone dominate, whereas isolates of G. rostochiensis alone are more frequent in the southern areas. In the eastern regions, mixed isolates are more representative. Most isolates examined in the western areas are mixtures of the two species or G. rostochiensis alone. Comparatively, G. pallida remains the most widely distributed species in its geographic range. This study confirms the presence of two PCN species, G. pallida and G. rostochiensis, in Algeria and provides additional information on their biogeographic distribution.

The potato cyst nematodes (PCN) Globodera rostochiensis and Globodera pallida are considered as being redoubtable pests of potato crop and are subject to strict quarantine regulations in several countries. In Algeria, the potato crop is the most important food crop widely cultivated in different agricultural areas. In this investigation, the response of three potato varieties; Kondor, Spunta and Desiree to the evolution of populations of Globodera spp. was studied. Final population of cysts, eggs and juveniles / kilogram of soil increased significantly in the variety Desiree compared to the initial population. A significant decrease was noticed in the variety Kondor. However, the variety Spunta did not show significance between the final and initial nematodes population. The effect of these nematodes on the tuber yield of various potato varieties was also studied. Variety Kondor produced the best yield while Desiree gave the least. The variety Kondor presented the best results in terms of resistance and yield. It is important to use this variety to control these pests.