Study of Arbuscular Mycorrhizal Fungi Diversity and Its Effect on Growth and Development of Citrus aurantium L.

Citrus aurantium L. is the most used rootstock in Morocco. The use of arbuscular mycorrhizal fungi can favor the good growth of this species. A study was conducted under the greenhouse to assess its reaction to mycorrhizal colonization. Citrus aurantium L. plants were inoculated at the stage of 2 leaves, with a local composite inoculum of AMF, originating from the rhizosphere of many species of Citrus. The growth and mycorrhizal parameters were observed seven months after inoculation. The results obtained showed that the inoculated plants had a growth significantly higher than the control ones, with a gain of 90.1%. Inoculation of the plants was also effective on the leaves emission, branches formation and growth of collar diameter, gains were respectively 266, 300 and 300%. The fresh weight of root and vegetative masses also showed higher values on the inoculated plants, with a gain of 478% and 425% respectively. The average frequency and intensity of root colonization by mycorrhizal fungi were 93.33% and 50.6% respectively. The number of spores formed at the rhizosphere of plants inoculated was 132/100 g of soil and they were represented by 23 species belonging to the genera Glomus (8 species), Acauolospora (9 species), Scutellospora (3 species), Pacispora (2 species) and Gigaspora (1 species). The beneficial effect of mycorrhizae on Citrus aurantium L. was discussed in this study.