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Comparison of growth, yield and related traits of resistant Hevea genotypes under high South American leaf blight pressure

Cardoso S.E.A., Freitas T.A., Da Silva D., Gouvêa L.R.L., De Souza Gonçalves P., Mattos C.R.R., Garcia D.. 2014. Industrial Crops and Products, 53 : p. 337-349.

Most natural rubber (NR) comes from the cultivation of Hevea brasiliensis in tropical areas. However,South American leaf blight (SALB), caused by Microcyclus ulei (P. Henn.) Arx, is the main factor limitingHevea cultivation in the American humid tropics. Based on a preliminary selection from among more than960 accessions, the aim of this work was to propose new SALB-resistant genotypes for South Americanplantations. Agronomic traits (SALB resistance, growth, production) and characters related to latex pro-duction, such as sucrose and inorganic phosphorus, along with structural traits of the bark of nine Heveagenotypes resistant to SALB (TP875, FDR5788, MDX608, PMB1, CDC429, CDC312, FDR4461, MDF180,SIAL893) were evaluated during the course of a 12-year trial located in the Michelin plantation (Bahia,Brazil). These genotypes presented a quantitative resistance to SALB characterized by partially sporu-lating lesions (anomorph stage). No sexual form of M. ulei (stromata, teleomorph stage) was found inFDR5788, MDF180, CDC312, PMB1. Only FDR5788 genotypes presented a higher NR yield than genotypeTP875 used as a control. For FDR5788, MDX608, CDC312 and PMB1, the estimated yields of 12-year-oldtrees were, respectively 2.6, 2.0, 1.8 and 1.2 t year?1ha?1. In all genotypes, medium sucrose and inorganicphosphorus concentrations were related to intermediate metabolism for cis-polyisoprene synthesis. Thelow yield of genotypes SIAL893 and MDF180 is related to the limited number of vessel rings, limitedtranslocation of sucrose in the latex, and a slow metabolism indicated by low average concentrations ofinorganic phosphorus in the latex. For the south east of the Bahia state, FDR5788 and CDC312 are rec-ommended for new planting areas because of their capacity to prevent teleomorph formation, combinedwith high NR yields. (Résumé d'auteur)

Mots-clés : caractère agronomique; latex; sélection; génotype; résistance génétique; microcyclus ulei; hevea brasiliensis; brésil; amérique du sud

Thématique : Génétique et amélioration des plantes; Maladies des plantes; Culture des plantes; Physiologie végétale : croissance et développement

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