Résumé
The effect of a composite endomycorrhizal inoculum, native to the rhizosphere of the olive tree, was studied on the growth of leek plants (Allium porrum L.). Inoculation of leek plants was carried out by contacting the root system of leeks with the inoculum endomycorrhizal derived from the olive tree rhizosphere. After five months of inoculation, a significant effect is observed on the growth of the inoculated plants according to witnesses. Indeed, the average values of the aerial weight (11.62 g) and root weight (18.52 g), the diameter (0.5 cm) and the number of leaves (7) of the inoculated plants are higher than those noted in the control plants, respectively 4.42 g, 7.95 g, 0.3 cm, 5.57. Moreover, the frequency and intensity of mycorrhization, respectively 96.66% and 50.33%, the arbuscules contents (44.33%) and vesicles (32.44%) are very important. The roots of control plants are not mycorrhizal. The average number of spores formed in the rhizosphere of the inoculated plants is 160 spores per 100 g of soil. These spores are those of 85 endomycorrhizal species belonging to 16 different genera: Glomus (34 species), Acaulospora (18 species), Gigaspora (5 species), Entrophospora (3 species), Scutellospora (5 species), Pacispora (2 species), Claroideoglomus (2 species), Dentiscutata (1 species), Septoglomus (1 species), Paraglomus (2 species), Rhizoglomus (2 species), Ambispora (3 species), Cetraspora (1 species), Funneliformis (1 species), Diversispora (4 species) and Viscospora (1 species). Statistical analyzes were performed by analysis of variance by the ANOVA test at the 5% level using the STATISTICA software. Leek, is a mycotrophic plant that can be used to multiply an endomycorrhizal inoculum suitable for use in nurseries, and to produce seedlings of different plant species that are vigorous and resistant to pathogens and water stress after transplantation.
Résumé
The present study is conducted to know the effect of certain cultural practices and the variation of temperature and humidity (bioclimatic stage, slope exposure) on the distribution and importance of the development of tuberculosis disease of olive trees, caused by Pseudomonas savastanoi pv. savastanoi(PSS), in Northwest of Morocco. 1584 trees of oleaster and olive trees (cuttings and grafts) were observed during the period 2013-2014 in several groves in the northwest regions of Morocco. The percentage of infection was calculated by the number of olive trees showing the symptoms of tuberculosis caused by Pseudomonas savastanoi pv. savastanoi. The intensity of the disease in the oleaster and the olive tree was determined by counting the number of knots. The prospection was showed that olive plots are more or less attacked by tuberculosis in the northwest part region of Morocco and more apparent in olive trees in development station in Zoumi and in Boukkara (North and West oriented slopes of 68% and 28% respectively). The percentage of infection was very high in oleaster and graft plants (31% and 28% respectively) in two humid stations (Zoumi and Boukkara). The intensity of the tuberculosis disease showed that oleaster trees are most attacked. The development of olive trees is highly influenced by the symptoms in branches. The fruit size and weight were significantly higher in healthy olive trees than in those showing the symptoms of tuberculosis.