Genetic parameter estimations of three traits used to evaluate South American leaf blight (SALB) in rubber tree
Dominique Garcia; Carlos Mattos; André Clément-Demange and Vincent Le Guen
Attack severity, sporulation intensity and stromata density are three symptoms of South American Leaf Blight caused by Microcyclus ulei (P. Henn.) v. Arx. evaluated in the field on one to three year-old rubber tree [Hevea brasiliensis (Willd. ex Adr. de Juss.) Muell.-Arg.]. This genetic study under epidemiologic conditions of the Michelin plantation, Itiquira, State of Mato Grosso – Brazil, used the data from two experimental fields made of 198 clones from 22 progenies. The results indicate that small-scale clone trial is an more adapted apparatus than the seedlings selection trial for achieving the best appreciation of individual values. Moreover, this paper shows high correlations among the three parameters and gives genetic prediction values. The interest for an evaluation of the three parameters is discussed. Finally, a selection with a calculated index shows that a selection under genetic values retains the same clones as a selection under phenotypic values.