South American leaf blight of Hevea. II. Early evaluation of clonal resistance.

The CIRAD experimental station in French Guiana is testing 31 Hevea clones from Asia, Africa and Latin America in a smallscale trial situated in forest naturally contaminated with Microcyclus ulei, the causal agent of South American leaf blight. Anadditional study of resistance to M. ulei under controlled conditions by artificially inoculating potted plants was used to investigate components of resistance and consolidate field results. Clones were evaluated for abscission rates, foliage density and disease severity over 3 years. Results revealed that the clones fell into 3 groups according to their geographic origins and susceptibility to M. ulei: highly susceptible (Asia), highly resistant (South America) and an intermediate group containing Asian clones or South American and Asian hybrids. Clones RRIC132, IAN3087, IAN2878, IAN873, IAN717 and RO38 showed total resistance to M. ulei, and CD-1078, GU164, GU198, GU969, IRCA519, IRCA570, IRCA573, IRCA621 and IRCA652 exhibited high levels of partial resistance. Promising clones were selected for a breeding programme aimed at improving resistance and for testing in a Microcyclus zone. A methodology for early evaluation of Hevea resistance to leaf diseases in field trials is also proposed.

Bibliographic Details

Main Author:	Rivano, F., autor. aut 50060
Format:	Texto biblioteca
Language:	- F
Subjects:	Clones., disease resistance, evaluation, germplasm, plant diseases, plant genetic resources, plant pathogenic fungi, plant pathogens, plant pathology, rubber plants, testing, varietal reactions, Natural immunity, Evaluation, Plant diseases, Germplasm resources, Plant, Phytopathogenic microorganisms, Rubber plants, Testing,
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