Physicochemical Bases of Resistance of Pearl Millet Pennisetum glaucum (L.) Seed Landraces of Benin Against Sitophilus oryzae L. (Coleoptera: Curculionidae)

Pearl millet ( Pennisetum glaucum (L.) R. Br.), despite its nutritional importance, is a neglected and underutilized species in Benin due to numerous constraints, including storage insect infestation by Sitophilus oryzae L. Identifying effective control methods, such as varietal resistance, is necessary to prevent the use of chemical insecticides that harm human and animal health. The effect of seven physical characteristics of the grain (seed shape, colour, texture, coat thickness, length, width and mass of 1000‐grain weight) and three secondary metabolites (condensed tannins, flavonoids and total phenolics) on the susceptibility of seven pearl millet landraces to S. oryzae was evaluated in the laboratory. The influence of the examined traits on the resistance parameters in S. oryzae was assessed through correlation, regression and path coefficient analysis. Based on the Dobie susceptibility index, only Somna and Sowaya landraces were classified as resistant to S. oryzae , while Zokpera, Amala koupètè, Gbeï and Henni‐tchiré were classified as moderately resistant and the white seeded landrace Amala kouhloumè was classified as susceptible. The adult emergence and damage caused by S. oryzae were negatively and significantly correlated with the flavonoids and total phenol content of the grains. The oviposition of S. oryzae females was strongly ( R = 0.828) influenced by the biochemical characteristics of pearl millet seeds. The direct positive influence of seed width on pearl millet resistance to S. oryzae suggests its importance in improving pearl millet seed resistance.