Synthèse bibliographique sur l’étude morphologique et pathogénique du Fusarium oxysporum f.sp.ciceris.

Abstract

In the work presented we have studied the vascular Fusariose of chickpea, a serious disease caused by Fusarium oxysporum f. sp. ciceris situated in Algeria and a lot of other countries. The research presented in this thesis consist of doing a bibliographical synthesis on the morphology and the pathogeny of the fungus that is responsible of the disease. The morphological identification is based on the similarities of the observable morphological characters which is important because it allows the characterization of the isolats of different regions. As for the taxonomy of the type Fusarium, the form of macronidia is the first important character for the identification of the species. However, there are also other morphological characters like the microconidias, chonidiophores and the chlamydospores. The knowledge of the pathogenicity of the parasite allows a better see of the strategies of fight againt the disease. The determination of the distribution of racec of F. oxysporum f. sp. Ciceris is fundamental for elaboration of appropriate ways against the disease according to different regions. The bibliographical Synthesis shows that the F.o.c present an optimal temperature of growth 25°C.the size of the conidias variable depending on the region of the prospected world and sometimes also depending on isolats. After 5 to 7 days of incubation in a temperature of 25°C, we have noted that in the shape of mycelia there is the existence of 4 mophotypes: cottony, fluffy, mucous flush, aged culture. The bibliographical synthesis that we carried out also shows that the pathogenic study based on the reaction of a differential host range compound of ten cultivars, the F. o. c. shows a pathogenic variability in the parasite, which is distributed on eight physiological races: 0, 1A, 1B/C, 2, 3, 4, 5 and 6 (Kapoor & al., 1992). The eight races of F. oxysporum f.sp. ciceris are also different depending on their pathotypes and their geographical distribution all around the world.