HOW TO EVALUATE THE RESISTANCE OR TOLERANCE OF PINEAPPLE VARIETIES TO NEMATODES ?

Abstract

Due to consumer pressure, the use of nematicide on pineapple farms must be strongly reduced and is presently forbidden in EU territories according to the new EU regulations. Different ways to control soil born parasites are under investigation and the research on the tolerance or resistance of varieties to nematodes is one of them. In Martinique a screening method is being developed based on greenhouse cultivation in tanks. The behavior of different varieties from CIRAD germplasm was studied after infestation with the nematode Rotylenchulus reniformis. Growth characteristics and nematode populations were observed during six months covering the classical two flushes of root development observed in our tropical conditions. ´D` leaves weight and length as well as plant opening were measured every month, the plant shoot and root system were analyzed six months after planting. Preliminary results indicate that plants of the cultivar Smooth Cayenne show a susceptible pattern with strong vegetative growth reduction, meanwhile MD-2 plants show a tolerance pattern with a high multiplication of nematodes, but a relatively reduced effect on growth. Among Ananassoides sp., one variety shows a strong resistance pattern with little impact on vegetative growth. CIRAD hybrids show different resistance patterns from high susceptibility to good tolerance. This method will be used to detect potential parents for the breeding program, to evaluate new hybrids and to identify highly contrasting behaviors in order to study resistance/tolerance mechanisms to nematodes in pineapple. (Resume d'auteur)