Abstract
To increase groundnut yields in Senegal, research has developed technical proposals. However, a systemic vision is needed to evaluate their performance in the context of farmers' fields. We compared three short-cycle groundnut varieties: Fleur 11, 55-33 and 55-437, on two farmers' fields with contrasting soil fertility levels, interacting with two levels of mineral fertilization and rhizobial inoculation. Trials were conducted in 2018, a year marked by a long rainfall break in during the vegetative phase of the crop. Varieties 55-33 and 55 437 reached half of their potential yield, while Fleur 11 only reached a quarter. Fleur 11 variety was severely affected by fungal diseases causing seedling mortality and pod rot. These diseases were particularly severe on the least fertile field. Effects of fertilizer application on yields were the lowest in the least fertile field. With an average of 114 nodules plant-1, the varieties showed a good nodulation capacity, suggesting effective nitrogen fixation. Fertilizer application stimulated nodulation, suggesting that nutrient availability, particularly phosphorus, is a limiting factor for symbiotic nitrogen fixation in these agroecosystems. Mycorrhization was intense, particularly on the least fertile soil. Bacterial inoculation had no effect on the measured variables. Stepwise regression showed that the variability in seed yield was primarily linked to soil carbon content and damage from soil-borne diseases, while fodder yield was primarily linked to the number of nodules per plant. While often ignored in current crop models, soil-borne diseases represent a major obstacle to improving groundnut yields and its symbiotic interactions with soil organisms in the studied agroecosystems. Combining disease resistance, symbiotic efficiency, and good fertilizer response, varieties 55-33 and 55-437 are valuable tools for improving the productivity of groundnut crops in marginal environments.