Do Ralstonia solanacearum-Resistant Tomato Varieties Withstand Root-Knot Nematodes? A Greenhouse Evaluation of Meloidogyne enterolobii Impact
Elodie Nevrile Dénadi COFFI *
Nematology Unit (UNema), Laboratory of Study and Management of Plant Pathogens (LaGON), Faculty of Agronomic Sciences, University of Abomey-Calavi, 01 BP 526 Cotonou, Benin.
Antoine AFFOKPON
Nematology Unit (UNema), Laboratory of Study and Management of Plant Pathogens (LaGON), Faculty of Agronomic Sciences, University of Abomey-Calavi, 01 BP 526 Cotonou, Benin.
Bruno Enagnon HOUNKPONOU
Nematology Unit (UNema), Laboratory of Study and Management of Plant Pathogens (LaGON), Faculty of Agronomic Sciences, University of Abomey-Calavi, 01 BP 526 Cotonou, Benin.
Saturnin AZONKPIN
Institut National des Recherches Agricoles du Bénin, Direction Scientifique, 01 BP 884 Cotonou, Benin.
Cocou Angelo DJIHINTO
Institut de Recherche sur le Coton, Antenne Régionale Sud, Laboratoire d’Entomologie de Cana, BP 143 Bohicon, Benin.
Florent Jean-Baptiste QUENUM
Genetics, Biotechnology and Seed Science Unit (GBioS), Laboratory of Crop Production, Physiology and Plant Breeding (PAGEV), Faculty of Agronomic Sciences, University of Abomey-Calavi, 01 BP 526 Cotonou, Benin.
*Author to whom correspondence should be addressed.
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.
Keywords: Bacterial wilt, root-knot nematodes, screening for resistance, Solanum lycopersicum, vegetable crops