LABORATORY SCREENING OF PINEAPPLE GERMPLASM FOR RESISTANCE TO THE LESION NEMATODE PRATYLENCHUS BRACHYURUS

ISHS Acta Horticulturae 425: II International Pineapple Symposium

Authors:	J.L. Sarah, L. Mesnildrey, E. Margueritte, M. Boisseau
Abstract: Early and rapid screening of germplasm for resistance to nematodes is very relevant for genetic improvement programs. The use of in vitro micropropagated plantlets allows to save time and space as compared to field screening. Such a method was developed and checked with different species, groups and varieties of pineapple against Pratylenchus brachyurus, the most damaging nematode pest in Western Africa. After 3–4 weeks of acclimatation to ambient conditions, plantlets in 450 cm³ pots are inoculated with a calibrated inoculum of nematodes (200 as an optimum). Estimation of nematode population in the roots should be made 15 weeks after inoculation. Results appeared to be reproducible, indicating that the method is reliable. Among the checked germplasm, nematode density into roots ranked gradually with no evidence of clearly resistant plants. Thus, resistance to P. brachyurus, if any, would be highly polygenic with poor chance to be usable for plant breeders. This confirms preliminary field studies although consistancy between field and laboratory screening remains to be checked. It may be noteworthy that in two different experiments, the less infested plants belong to the ‘Pernambuco’ group.
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