%0 Journal Article
%T Etude de la sensibilit¨¦ des clones d¡¯Hevea brasiliensis (Muell. Arg.) ¨¤ l¡¯encoche s¨¨che
%A KM Okoma
%A K Dian
%A D Allou
%A A Sangare
%J Sciences & Nature
%D 2009
%I 
%X Chez Hevea brasiliensis, la production de latex est affect¨¦e par l¡¯encoche s¨¨che qui se manifeste par l¡¯arr¨ºt de l¡¯¨¦coulement de latex apr¨¨s la saign¨¦e. La sensibilit¨¦ clonale ¨¤ cette maladie est mal connue. La pr¨¦sente ¨¦tude a pour objectif d¡¯¨¦tablir une classification des clones les plus plant¨¦s en C te d¡¯Ivoire selon leur sensibilit¨¦ ¨¤ l¡¯encoche s¨¨che, dans des conditions d¡¯exploitation utilisant divers niveaux de stimulations ¨¤ l¡¯Ethrel. La m¨¦thode utilis¨¦e est l¡¯analyse de variances des longueurs d¡¯encoche malade collect¨¦es pendant cinq ans. Les r¨¦sultats ont montr¨¦ que les clones d¡¯h¨¦v¨¦a n¡¯ont pas la m¨ºme sensibilit¨¦ ¨¤ l¡¯encoche s¨¨che. Les clones IRCA41, PB 217, AF 261 et RRIM 712 sont peu sensibles ; IRCA 130, AVROS 2037, IRCA 209 et GT 1 sont moyennement sensibles ; RRIC 100, IRCA 230, et PB 254, sont sensibles ; et PB 260 et PB 235 sont tr¨¨s sensibles. La sensibilit¨¦ clonale ¨¤ l¡¯encoche s¨¨che suit un gradient identique ¨¤ celui de l¡¯activit¨¦ m¨¦tabolique des clones. Elle est corr¨¦l¨¦e positivement ¨¤ la fr¨¦quence de stimulation de l¡¯arbre ¨¤ l¡¯Ethrel. Les clones peu sensibles supportent mieux la stimulation ¨¤ l¡¯Ethrel ¨¤ l¡¯oppos¨¦ des clones tr¨¨s sensibles. Dans une parcelle monoclonale, certains arbres seraient pr¨¦dispos¨¦s ¨¤ exprimer, pr¨¦cocement, l¡¯encoche s¨¨che. In rubber tree, Hevea brasiliensis, latex production is affected by tapping panel dryness that appears by stopping the latex out-flow after bled. The clonal sensitivity to this disease is not well known. The objective of the present study is to establish a classification of the more planted clones in C te d¡¯Ivoire according to tapping panel dryness sensitivity, in operating conditions using various Ethrel stimulations levels. The method used is the analysis of variances of the panel sick lengths collected during five years. The results showed that rubber tree Hevea brasiliensis clones have not the same sensitivity to tapping panel dryness. The IRCA41, PB 217, AF 261 and RRIM 712 clones are little sensitive; IRCA 130, AVROS 2037, IRCA 209 and GT 1, are fairly sensitive ; RRIC 100, IRCA 230, and PB 254, are sensitive ; and PB 260 and PB 235, are very sensitive. The clonal sensitivity to tapping panel dryness follows a gradient identical to those of the clones¡¯ metabolic activity. It¡¯s positively correlated to the Ethrel stimulation frequency. Little sensitive clones support the Ethrel stimulation better than very sensitive clones. In a monoclonal plot, some trees would be predisposed to express tapping panel dryness precociously. Mots cl¨¦s/
%U http://www.ajol.info/index.php/scinat/article/view/48576