Do Ralstonia solanacearum-Resistant Tomato Varieties Withstand Root-Knot Nematodes? A Greenhouse Evaluation of Meloidogyne enterolobii Impact

Abstract

Root-knot nematode, Meloidogyne enterolobii, is an emerging threat to tomato production due to its wide host range and ability to overcome existing resistance. This study evaluated whether tomato varieties resistant or susceptible to Ralstonia solanacearum also exhibit resistance to M. enterolobii. Twelve tomato genotypes, AVTO 1955-15, CLN 2498D, CLN 4018G, CLN 4270F, Padma 108 F1, F1 Cobra 26, F1 Thorgal, F1 Mongal, Petomech +, Tropimech, Akikonkouin and Tounvi, were screened under greenhouse conditions by inoculating each plant with 1,000 second-stage juveniles (J2) and eggs of M. enterolobii in the first experiment and 1,500 nematodes in the repeat experiment. Both experiments were laid out in completely randomized design with five replicates. Nematode reproduction factor (RF), galling index (GI), plant growth parameters, and physiological traits such as chlorophyll content and photochemical yield (Fv/Fm) were assessed. At harvest, the GI values ranged from 4.0 to 7.8 and RF values > 2. This suggests that all varieties were susceptible to M. enterolobii under tested conditions, although F1 Cobra 26 and CLN 4018G showed relatively lower nematode reproduction and root galling. Nematode infection significantly reduced plant growth and photosynthetic efficiency. These findings highlight the need for integrated nematode management and support the inclusion of nematode resistance screening in tomato breeding programs, particularly for dual-pathogen environments.