Réaction de quelques lignées de pois chiche (Cicer arietinum L.) vis-à-vis des pathotypes I et III de Ascochyta rabiei (Pass.) Labr., agent causal de l’anthracnose et effet du parasite sur la teneur en flavonols, en azote et en chlorophylle.

Abstract

The work presented in this document contributes to the study of the anthracnose of chickpea (Cicer arietinum L.), disease caused by Ascochyta rabiei, present in Algeria and in several countries of the world. The reaction of four chickpea lines belonging to ICRISAT (Flip 09-320C, Flip 09-387C, Flip 09-430C, Flip 9393C) was studied with respect to two pathotypes of A. Rabiei, pathotype I (weakly aggressive) and pathotype III (highly aggressive). Two techniques are used: technique of inoculation of whole seedlings and technique of detached leaves. The results confirm the existence of pathogenic variability in Ascochyta rabiei and a difference in susceptibility in the inoculated chickpea lines, whether it is the technique using whole seedlings or detached leaves. The technique of inoculation of the whole seedlings shows that all the tested lines are very sensitive to pathotype III (attack index equal to 9, on the rating scale of Singh et al., 1981), where as two lines are sensitive (Flip 09-320C and Flip 09-387C) and two resistant (Flip 9393C and Flip 09-430C) to Pathotype I. The detached leaf technique does not show any difference between the lines inoculated with pathotype I, but it confirms the results obtained by the technique of whole seedlings, the sensitivity of all the lines to pathotype III . After inoculation of two weeks old seedlings with a pathotype III isolate, measurements of three parameters (nitrogen, chlorophyll and flavonols) were carried out on the ventral surface and the dorsal surface of a leaflet per seedling, according to a kinetic over time (5, 7 and 9 dpi). The analysis of variance shows a highly significant difference between the two faces of the leaflet for all the parameters studied and the notations performed over time. A highly significant difference is noted between the lines for chlorophyll and flavonol parameters. There is also a highly significant difference between the control and the inoculated for the nitrogen parameter. The nitrogen content decreases in the inoculum in a highly significant manner compared to the control.