Genetic mapping and QTLs detection in a Theobroma grandiflora progeny : S04P01

Abstract

The genus Theobroma covers 22 native species to the Amazon region. Two species are cultivated in Brazil:Theobroma cacao and T. grandiflorum (cupuaçu). T. grandiflora is economically important to the amazonian states of Brazil where it was developed in food and cosmetics with various products manufactured mainly from the pulp of the seed. Both species are susceptible to Moniliophthora perniciosa (Stahel) Singer, the causal agent of witches' brooms disease. 139 SSRs markers (Single Sequence Repeat) from T. grandiflora and 500 SSRs developed by CIRAD in T. cacao, were used to select polymorphic markers and carry out a genetic mapping of a Th. Grandiflora progeny from "174" x "1074" clones, respectively resistant and susceptible to witches' brooms. 145 plants were obtained by Embrapa-CPATU (Belém) today installed in the field at the CEPLAC (Belém) station. Inoculations with the M. perniciosa (from T. grandiflora) were carried out in the progenies and parents to evaluate the resistance. Other observations as vigor or number of ovules per ovary were observed also. We present the first results obtained with the selection of polymorphic specific markers of Th Grandiflora and Cocoa and the first genotying results from 44 SSRs of T. grandiflora including 14 SSRs from expression sequences. In conclusion this study including different teams is ongoing to have at the end of the project: i) the first genetic map of Theobroma grandiflora, ii) identification of QTLs of resistance to witches' broom, and other QTLs and iii) to compare genetic map and QTLs between both species. (Texte intégral