Quantitative trait analysis in Theobroma cacao using molecular markers - Yield QTL detection and stability over 15 years

Citation
D. Crouzillat et al., Quantitative trait analysis in Theobroma cacao using molecular markers - Yield QTL detection and stability over 15 years, EUPHYTICA, 114(1), 2000, pp. 13-23
Citations number
35
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
13 - 23
Database
ISI
SICI code
0014-2336(2000)114:1<13:QTAITC>2.0.ZU;2-E
Abstract
The aim of this study was to determine the genetic components controlling y ield in an F-1 cacao cross between Catongo and Pound 12 clones. Genetic map s were constructed for the two parents using molecular markers which detect ed 158 polymorphic loci covering 772 cM for the heterozygous genotype Pound 12 and only 4 loci representing 16.9 cM of a linkage group which indicated a high level of homozygosity of Catongo. Yield was recorded twice a month during 15 years on 55 individuals from this segregating population. Ten yie ld QTL were detected on eight linkage groups. Some of these QTL were freque ntly detected over 15 years of production, while others were specific for a given year. Total yield genetic variance, on a yearly basis, ranged from 0 to 56%. Two major QTL (E and I) each explained approximately 20% of the to tal variance of the average yield over 15 years. The analysis of potential cacao yield components, such as pod index and trunk diameter, suggested tha t some regions of the genome exert effects on more than one trait, providin g a possible genetic explanation for the correlations detected between some of title traits studied. Data showed that correlation between successive a nnual yield decreased when the lag between corresponding seasons increased. When separated by more than 10 years, annual yields were no longer correla ted. The utilisation of molecular markers alone or in combination with phen otypic selection showed an advantage in the early selection of the best cac ao producer trees. Further use of molecular markers in breeding programs is discussed with a view to reducing the generation time of a selection proce dure.