Dry season performance of tomato hybrid Chistera F1 against the Ralstonia–Meloidogyne complex and associated biotic constraints in a tropical epidemic hotspot

Intensive off-season tomato production in West Africa is constrained by the synergistic Ralstonia solanacearum–Meloidogyne spp. complex. This study evaluated the resilience of seven hybrids, including the candidate Chistera F1, in an epidemic hotspot in Côte d’Ivoire. Performance was quantified using a weighted Global Pathological Pressure Index (GPPI) and a Varietal Stability Index (VSI). Results confirmed a severe pathosystem where susceptible varieties collapsed. Chistera F1 demonstrated exceptional tolerance to complex biotic pressure (GPPI = 6.96%) and high phenotypic stability (VSI = 0.908), significantly outperforming the regional control Cobra 26 (GPPI = 10.24%). Multivariate analysis (74.2% of variance explained) validates strong correlations between bacterial wilt and nematodes (r > 0.93), confirming the ecological facilitation model. Chistera F1 is thus identified as a highly promising genetic candidate to mitigate the cycle of sanitary decline in tropical high-pressure zones.