Reproductive Fitness and Pathogenicity of Eight Radopholus similis Isolates on Banana Plants (Musa AAA v. Poyo)

Abstract

Eight isolates of Radopholus similis were compared for their reproductive fitness and pathogenicity on banana (Musa AAA cv. Poyo) under controlled conditions in a climatic chamber. Five isolates were originally collected from African countries (Uganda, Cameroon, Nigeria, Ivory Coast, and Guinea) and the 3 others from Guadeloupe, Queensland, and Sri Lanka. The African isolates, and particularly the one collected in Uganda, had the highest reproductive fitness. Strong negative correlations were observed between nematode numbers in roots 6 and 8 weeks after inoculation and fresh root and shoot weights 12 weeks after inoculation. These results suggest that differences in pathogenicity on banana among R. similis isolates are a direct consequence of differences in reproductive fitness on banana tissue, and consequently that the relative virulence is roughly similar for all isolates considered. This study increases our knowledge of the biological intraspecific diversity of R. similis throug