Quantitative trait loci analysis in Theobroma cacao using molecular markers. Inheritance of polygenic resistance to Phytophthora palmivora in two related cacao populations - Polygenic resistance to Phytophthora palmivora in cacao

Citation
D. Crouzillat et al., Quantitative trait loci analysis in Theobroma cacao using molecular markers. Inheritance of polygenic resistance to Phytophthora palmivora in two related cacao populations - Polygenic resistance to Phytophthora palmivora in cacao, EUPHYTICA, 114(1), 2000, pp. 25-36
Citations number
43
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Plant Sciences
Journal title
EUPHYTICA
ISSN journal
0014-2336 → ACNP
Volume
114
Issue
1
Year of publication
2000
Pages
25 - 36
Database
ISI
SICI code
0014-2336(2000)114:1<25:QTLAIT>2.0.ZU;2-J
Abstract
Two related segregating populations of Theobroma cacao L. were analysed for their resistance to Phytophthora palmivora. The first F-1 population was o btained by crossing two susceptible cacao clones of Catongo (a highly homoz ygous genotype) and Pound 12 (a highly heterozygous genotype) and the secon d population was obtained by backcrossing a single F-1 tree with Catongo. T he genetic maps obtained for each population were compared. The F-1 map inc ludes 162 loci and the backcross has 140 loci. The two maps, F-1 and BC1, e xhibit high co-linear loci organisation covering respectively, 772 and 944 cM. Phytophthora resistance was assessed by measuring the size increase of a lesion at five (DL5) and ten days (DL10) after pod inoculation. Six diffe rent QTL were detected in the F-1 and BC1 populations. One QTL was found in both populations, and appeared to be a major component of disease resistan ce, and explaining nearly 48% of the phenotypic variance in the F-1 populat ion. The absence of some yield QTL detection in the BC1 in comparison with the F-1 population is due to the lack of transmission of the favouring alle les for these QTL from the single F-1 tree used for the backcross. The phen otypic variance explained by the action of the quantitative trait alleles i ndicated that genetic factors of both major and minor effects were involved in the control of the character studied. QTL conferring increased resistan ce to Phytophthora were identified in both susceptible parents, suggesting the presence of transgressive traits and the possibility of selection in ca cao. Pleiotropic and epistatic effects for the QTL were also detected. Fina lly, the use of marker assisted selection (MAS) in cacao breeding programs is discussed.