Etude par les isozymes de la pollinisation libre de génotypes d'hévéas sauvages (Hevea brasiliensis Muell. Arg.) en verger à graines

Abstract

Survey of the open pollination by isozymes in a wild rubber trees (Hevea brasiliensis Muell. Arg.) seeds orchard. The Côte dʼIvoire has a wild rubber tree population for which an improvement in a seeds orchard is suggested by open pollination. The isozymes markers (5 loci) were applied to study the open pollination in a rubber tree seed orchard in 1998 and 1999. The results confirmed the allogamic character of the rubber tree. On the period of the survey (1998 and 1999), the outcrossing rate estimated to 0.97 and 0.96 varies weakly between the two years. The high level of the outcrossing rate show that pollinations are realized between trees of different genotypes. The fixation index (FIS) decrease from the parental population to the descendantʼs one where it is not significantly different from zero. So crossings are panmictics, and the fertilizations between the related trees are practically inexistent. The rate of self-fertilization is mostly due to the real self-fertilizations between the ovuls and the pollen coming from the same origin. Thus, considering the results, the pollination in the seeds orchard would be favorable to the realization of substantial genetic progress in the wild rubber trees population.

Keywords

• Hevea brasiliensis
• open pollination
• seeds orchard
• mating system
• outcrossing
• genetic diversity