Effects of two Ralstonia solanacearum strains on yield of tomato (Lycopersicon esculentum mills 1768) genotypes planted at three different planting seasons at the Sotuba station, Sudano-Sahelian area of Mali

The tomato, a genus of Lycopersicon, is cultivated worldwide for fruit. It is an important gastronomic ingredient and an important source of income for small farmers in Mali. However, its production faces a number of phytosanitary constraints that are still poorly understood. Among phytosanitary problems, bacterial wilt, caused by R. solanacearum , is proving to be the most dangerous and devastating of all tomato crops in Mali. The aim of this study is to contribute to the improvement of tomato production in Mali by identifying tomato varieties tolerant to R. solanacearum and adapted to the growing periods. To achieve this objective, trials under artificial and natural infestation conditions with 12 tomato genotypes during three periods were conducted at the Sotuba research station from December 2018 to December 2019. Analysis of variance revealed no significant difference between the two strains tested. Both strains were more severe, especially in period 2 of the experiment. The Caraïbo variety was the most susceptible to both strains, with an average severity rate of 2.8 (≈3) and the most stress-susceptibility index (0.69). The varieties Carioca and SF-83-61 were the most productive in both experimental conditions. With average yields ≥ 3.5 t/ha under artificial infestation conditions and ≥ 6 t/ha under natural conditions. In contrast, the Roma and Rossol varieties recorded the lowest yields. To minimize R. Solanacearum damage and improve field yields at all cropping periods, the SF-83-61 and Carioca varieties may be recommended for release in areas where R. Solanacearum , responsible for bacterial wilt, causes significant damage in tomato crops after confirmation tests.