Étude synthétique des réactions induites par les nématodes phytoparasites sur le bananier Musa acuminata (groupe AAA) : hiérarchisation des paramètres adaptés à la sélection variétale

Abstract

The susceptibility of bananas to phytoparasitic nematodes, the damages caused by nematodes, and the plant defense reactions can be evaluated respectively by the multiplication rate of parasites, the plant growth and metabolism, and the modifications of the secondary metabolism. The comparison, through multivariate analyses, of these four groups of parameters between two banana cultivars (Poyo and Gros Michel), differently susceptible to nematodes, helps to hierarchize the importance of these groups. So, the variables associated with shoot and root growth and the variables associated with plant physiology (photosynthesis, carbon metabolism, nitrogen and mineral absorption) are quite bad parameters because they evolve anarchically with the initial nematode population pressure. On the opposite, the final nematode population pressure and the variables associated with host defense reactions (secondary metabolism) are more reliable because they give more homogeneous results. It is then possible to assess the usefulness of the parameters describing banana susceptibility to nematodes and to give reliable criteria to geneticians for nematode resistance breeding programs. Key words: banana, defense reactions, phytoparasitic nematodes, resistance, tolerance, cultivar behaviour. [Traduit par la rédaction]