1. ABSTRACT INTRODUCTION Introduced in Morocco in the early 40s, bananas were initially confined to small open field plantations in a few locations with a suitable microclimate along the Atlantic Coast, North of Agadir. Since the first successful attempts to produce this crop in plastic greenhouses in the early 80s, the expansion was accelerated by government finance support, which reached 70 % of the total investment cost. Today, the valley of Souss-Massa, in the Agadir region, is the main area of banana production in the South of Morocco. The introduction of intensive cultivation systems has resulted in an increase in the importance of plant-parasitic nematodes as a limiting factor of banana production in Morocco. The most widespread and damaging nematodes associated with banana in Morocco are Meloidogyne javanica, Helicotylenchus multicinctus, and Radopholus similis (Ferji and De Waele, 1998). Despite the presence of these nematodes in Morocco and the damages and yield loss they cause in bananas, we lack detailed studies on their distribution in relation related to the soil factors. This present study aims to map the geographical distribution of the predominant nematode species in the most important banana growing areas and to determine the relationship between abiotic pedological parameters (environmental conditions) and plant-parasitic nematode species. RESULTS & DESCUSSION Nematological and soil factors analysis Soil factors analysis - The performed PCA shows that the horizontal axe gives a particles sizes gradient and opposes sand with positives coordinates to clays and silts which are highly correlated (Figure 1A). The second axe is linked to some chemicals gradients (Fe, Cu, Zn, Mg and NO3). The copper (Cu) and iron (Fe) ions have a positives coordinate whereas, the zinc (Zn) nitrogen are in the opposite side. - Fields projection (Figure 1B) shows a clear separation of the fields according to their origin aerea. Massa fields are characterized as sandy soil. In contrast, located, fields in Ouledteima has a high content of silts, clays and limestones. Lahmar fields an intermediate position with a a loamy soil texture but rich in zinc (Zn) and nitrogen (N.NO3). Nematological analysis -In the factor map of the second PCA (Figure 1C) on the nematological data, the first factor shows that Meloidogyne spp. and Tylenchorynchus spp. is placed in the right part of the map with positives coordinates, while Longidorus spp. Helicotylenchus multicinctus, Radopholus simulis and Creconema curate are in the opposite side with negative coordinates. -The second axis opposes Creconemella mutabula with positives coordinates to Tylenchorynchus spp., Tylenchulus spp. and Helicotylenchus pseudorobustus. - The projection of most Massa fields in the right of first axe reveals its high infestation by Meloidogyne spp. whereas the position fields from Ouledteima shows a high infestation of Radopholus simulis. Nematode-soil factors relationship for banana crop -both factor maps established from fauna and soil data were approximately similar to those of the PCA. The factor map derived from the nematological data (Figure 2 C, D) rotated around the horizontal axis to reinforce some relationships and the gradient of soil particle size (texture) presented by the first axe was conserved. -This confirmed the link between the sandy soil located in Massa and the presence of Meloidogyne, whereas Helicotylenchus multicinctus and in particular, Radopholus similus were associated with the fields on Ouledteima, which are rich in clays and silts. -In contrast, Tylencorynchus, Tylenchus and Helicotylenchus pseudorobutus which position in center indicate that they are independant on soil texture and seem to be linked weakly to the limestone gradient. CONCLUSION -The phytoparasitic nematodes associated to banana crop in the south of Morocco are very closely linked to soil texture especially concerning Meloidogyne spp. and H. multicinctus. -H. multicinctus occurred mainly in loam to loam-clay soil whereas Meloidogyne spp. was present in all areas surveyed but with an important link to sandy soil. -Further studies are needed concerning the relationship between this most important phytoparasitic nematodes and other abiotic and biotic factors to built an agro- ecological management strategies. MATERIALS AND METHODS A total of 53 farms from three main bananas growing areas in Agadir region were surveyed: Souss- Massa, Ouled taima and Lahmer. From each farm 10 mats were sampled in one (homogenous) hectare. Roots and soil were collected from an excavation extending outward from the corm of recently flowered plants. Soil texture, the use of nematicide and crop histories was recorded. Soil texture and chemical analysis was determined in the laboratory of soil science at the Hassan II veterinary and Agronomic Institut in Agadir. To characterize the nematodes species and soil parameters relationship, the two table data were coupled by coinertia analysis Computations and graphical displays were made with the ADE-4 software (Thioulouse et al., 1997). The pertinence of coinertia analysis was tested by Monte Carlo permutation test. Figure 2: Factor maps (F1 x F2) of the co-inertia analysis on soil parameters (A, B) and banana parasitics nematodes species (C, D) fields maps of the coinertia on banana nematodes abundance. On the factor maps, the fields are grouped according to the region to which they belong on the south of Morocco; Cr.c : Creconema curvata, C.mu : Creconema mutabile, Hel.m : Helicotylenchus multicinctus, Hel.p : Helicotylenchus pseudorobustus, Mel: Meloidogyne spp., Rad.s : Radopholus simulis, TyLr: Tylenchorynchus, Tyl : Tylenchus spp.. Figure 1: Correlation circle and factor maps (F1 x F2) of the PCA on pedological parameters for banana fields (A and B) and on on banana nematodes abundance (C and D); Cr.c : Creconema curvata, C.mu : Creconema mutabile, Hel.m : Helicotylenchus multicinctus, Hel.p : Helicotylenchus pseudorobustus, Mel: Meloidogyne spp., Rad.s : Radopholus simulis, TyLr: Tylenchorynchus, Tyl : Tylenchus spp. A nematode survey conducted in a banana plantation in plastic greenhouses located in the region of Agadir, South of Morocco, leads to a study to determine the relationship between abiotic pedological parameters (environmental conditions) and the important plant-parasitic nematode species. About Five hundred and thirty root and soil samples were collected from the most important producing areas and were examined for plant parasitic nematodes in comparison to the analysis of soil chemical composition and texture. To identify the main factors that influence the spatial repartition of the nematodes we performed a co-inertia analysis by R software. Among the eleventh prospected genera of nematodes identified, only the most important phytoparasitic nematode to banana crop, Helicotylenchus multicinctus, showed a correlation with soil factors, in particular the texture of the soil. This nematode was found mainly in loam to loam-clay soil. By contrast, Meloidogyne spp. was found in all areas surveyed but with a close association to sandy soil. Radopholus similis was mainly found in loam-clay soil, however, its distribution was found to be also associated with the transplantation of infected suckers. Key words: Phytoparasitic nematodes, banana, soil factors, co-inertia. REFERENCE Ferji, Z., De Waele, D. 1998. Occurrence, abundance and distribution of nematodes on banana grown in plastic greenhouses in south Morocco. 24th International Symposium European Society of Nematologists. Dundee, Scotland, 5-8 August 1998. Thioulouse J., Doledec S., Chessel D., Olivier J. M., 1995. ADE software: multivariate analysis and graphical display of environmental data. In: Guariso, G., Rizzoli, A. Eds., Software perlambiente. Patroneditore, Bologne, pp. 5762. A B CD