In Chad, rice is grown for its starchy seeds or caryopses, but is also for consumption in the form of seeds pasta with soup. However, little or no work has been conducted in Chad to assess the composition of endomycorrhiza community inhabiting the plant rice rhizospheres. Hence, the main objective of this study was to investigate on native endomycorrhiza that are efficient to establish a symbiotic relationship with two rice varieties in the Sahelian zone in Chad. Two rice varieties were grown in a pot experiment on composite soils samples from Laï, Kelo, Kolobo and N’Djamena for 3 months. Parameters such as mycorrhizal frequency, intensity, specific density and richness were determined following to the standard methods. After spore extraction, species description and characterization were obtained through the informations provided by the International Vesicular Mycorrhizal fungi collection (INVAM): http://invam.caf.wv.edu/fungi/taxonomy/species ID.htm. The highest specific endomycorrhizal density (97.3%) and richness (11%) were registered respectively at kelo, Laï and Kolobo. The endomycorrhizal frequency and intensity were respectively between 4.33-7.33% and 0.8-2.9% for the two rice varieties. Eleven endomycorrhiza species belonging to six genera were identified from different soil samples. These include Septoglomus (S. constrictum, S. deserticola); Rhizophagus (R. aggregatus, R. fasciculatus, R. intraradices); Acaulospora (A. lacunosa, A. rugosa, A. trappei); Claroideoglomus lamellosum; Glomus pansihalos and Diversispora epigae. S. constrictum was the most dominant and frequent species found in all the soil sampling sites, while R. aggregatus was the less frequently encountered specimen. The lowest macorrhizal richness and frequency obtained is a proof that cultivation of rice dependent on endomycorrhiza in this zone. The multi-native endomycorhiza spores identified are the active principle to be included in the bioinoculants production in order to increase and improve the production of rice in the south of Chad.

This work investigates on the morpho-anatomical diversity of arbuscular mycorrhiza fungus spores native to soybean rhizosphere in the agro-ecological zone I of Cameroon. Arbuscular mycorrhiza fungi spores have been trapped in pot on composite soils samples taken from three areas in each northern region. Soybean have been used as host plant. After 90 days of growth, the mycorrhizal fungus spores have been extracted and the host plant roots stained. Results analysis revealed that the mycorrhization frequency (F) and intensity (I) are higher at Maroua area (F = 4.6%, I = 3.95%) and lower at Guider zone (F = 1.33% and I = 1.22%). For the specific density, the values vary between 1.54% (Guider zone) and 5.2% (Yagoua zone). Regarding the specific richness, the obtained data fluctuate between 3% (Guider) and 8% (Mokolo). The morpho-anatomical characterization of the spores indicated the presence of 9 different specimens: Septoglomus constrictum, Glomus maculosum, Glomus manihostis, Acaulospora kentinensis, Acaulospore myriocarpa, Rhizophagus intraradices, Ambispora sp, Funneliformis mossea, Diversispora epigae. Among these strains, Septoglomus constrictum is the most abundant specimen while Funneliformis mossea, Ambispora sp and Acaulospora myriocarpa are the rarest. The agronomic performances of these strains can be evaluated for and ecological production of soybeans in the agro-ecological zone I of Cameroon.

This work aims to assess the leek-arbuscular fungus symbiosis response to the effect of cutting and light exposure on the one hand, and the impact of seedling density on this symbiosis on the other hand. Allium Porrum was grown in a container in two different trials. Four species of arbuscular mycorrhizal fungi, Glomus hoi, Scutellospora gregaria, Rhizophagus intraradices and Gigaspora margarita were used to constitute the mycorrhizal inoculum. After 150 days of growth and inoculation, a series of cuts were made on the aerial part (0% = zero cut, 50% = half cut, 100% = whole cut). Plants that had undergone these treatments were placed in shade and sun for 30 days. The leek density per bag was varied by the order of 1, 2, 3 and 4 plant (s) by the pocket density test. Results showed that for 0% of cut in the shade, the vesicle occurrence decreases from 83.33% to 52.22%, and from 90% to 25.5% for 50% of cut in the shade. On the other hand, there is a significant increase in intra-root spores for a complete cut compared to other levels of cuts. For extra-root sporulation, under light, cuts have a negative and weak effect (from -11 to -3%) while in the absence of light, cuts have significant positive effects (from +16 to +61%). Regarding seedling density, the best root colonization (90%) and biomass production (14 g) are obtained with three plants per pot, but it is rather with a density of two plants per pot that extra-root sporulation is higher (153 spores/g). Variation in light, cut level and density significantly affects the development of mycorrhizal fungi.