A genetic linkage map of Theobroma cacao L.

Abstract

A linkage map of the cocoa genome comprising 193 loci has been constructed. These loci consist of 5 isozymes, 101 cDNA/RFLPs, 4 loci from genes of known function, 55 genomic DNA/RFLPs and 28 RAPDs. A population of 100 individuals derived from a cross between two heterozygous genotypes was used. Segregation analyses were performed with the JoinMap program. Ten linkage groups, which putatively correspond to the ten gametic chromosomes of cocoa, were identified. The map covers a total length of 759 cM with a 3.9 cM average distance between 2 markers. A small fraction (9%) of the markers deviated significantly from the expected Mendelian ratios.

Pathogenic variability of Moniliophthora perniciosa in three agroecological zones of the cacao region of Bahia, Brazil

“…The identification of QTL (Quantitative Trait Loci) reinforces this argument (Lanaud et al 1995, Crouzillat et al 1996, Motilal et al 2002, Pugh et al 2004. This is the reason that progenies of Scavina clones crossed with other resistance sources maintain a resistant performance in the field .…”

Cacao domestication I: the origin of the cacao cultivated by the Mayas

“…This class also included material from germplasm collections in Costa Rica, Cô te d'Ivoire, Mexico, Venezuela and France. 'Modern Criollo' represents the genotypes studied as Criollo in previous biochemical and molecular studies (Lanaud, 1987;Bekele and Bekele, 1998;Ronning and Schnell, 1994;Laurent et al, 1995;N'Goran et al, 1994;De la Cruz et al, 1995;Lerceteau et al, 1997;Whitkus et al, 1998).…”

“…For RFLP analyses, DNA was isolated using ultracentrifugation in a caesium chloride-ethidium bromide gradient as described in Lanaud et al (1995). For microsatellite analysis, DNA isolation was performed as described in Risterucci et al (2000); after total resuspension, a QIAGEN genomic-tip was used to purify the DNA according to the manufacturer's instructions.…”

“…RFLP procedures: All RFLP procedures were conducted as described previously (Lanaud et al, 1995). EcoRI and HindIII were used for genomic DNA restriction.…”

“…DNA probes: Seventeen cDNA and eight genomic DNA probes, chosen for their coverage of the genetic map of T. cacao (Lanaud et al, 1995), were used to study 283 individuals.…”