Rice (Oryza sativa L.) forms a vital part of the diet of almost three billion people worldwide. Increasing rice production is crucial to meeting the demands of this ever-growing population. This study examines how the agromorphological and biochemical characteristics of two rice varieties are affected by symbiosis with beneficial microorganisms. The study used a completely randomized block design with two factors and was conducted in the botanical garden of the Faculty of Sciences at the University of Yaoundé I in central Cameroon. To achieve this, the agronomic (plant height, stem diameter, number of thalli per plant, number of panicles per capsule, weight of ears per plant, and 1000-grain weight) and biochemical (contents in total chlorophyll, total soluble sugars, and proline) traits of the rice varieties (main factor) Nerica L8 (improved) and Tonga (local), were evaluated in response to the following treatments (secondary factor): T0 (control), T1 (mycorrhizae), T2 (endophyte), T3 (endophyte and charcoal), T4 (endophyte, charcoal, and mycorrhizae) and T5 (urea). This study showed that urea treatment (T5) was the most effective, with the highest values for all agromorphological traits. These included an average plant height of 105.45 ± 6.06 cm, an average stem weight per plant of 8.27 ± 2.80 g and an average weight of 1000 grains of 36.10 ± 0.10 g for Nerica L8. Conversely, the mycorrhizae-inoculated treatments (T1 and T4) had high root colonization rates ranging from 88.53% to 96%. The results revealed a higher number of spores (53 spores/g of soil for Nerica L8 and 42 spores/g for Tonga) and greater mycorrhizal dependency in treatment T1 (+59.11% for Nerica L8 and +50.80% for Tonga). Furthermore, treatments T4 and T2, which contained mycorrhizae, resulted in a significant accumulation of total chlorophyll, total soluble sugars and proline in both rice varieties studied (P < 0.05). This study suggests that using mycorrhizae and urea, either separately or together, could be key to improving rice yields.
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