Abstract
Black pod disease on cocoa can be caused by different species of Phytophthora. Our study includes three species found in producing countries: P. palmivora, worldwide, P. megakarya so far only present in Africa and P. capsici present in Latin America.The two parents of the mapping population are Scavina 6, an Upper Amazon Forestaro clone, and C1, an amelonado clone. Scavina 6 is highly resistant to Phytophthora. The cross was made in Cote d'Ivoire. BC 1 population of 151 individuals was in green house in Montpellier (France) and used for genetic linkage and QTL analyses. Resistance evaluation was made by artificial inoculation on leaf discs. Two strains of each species were used. The segregation of 202 markers was analysed using a LOD score of 4.0 to identify the linkage groups. All the markers were assigned to ten linkage groups that putatively correspond to the ten gametic chromosomes of Theobroma cacao. These loci include 191 AFLPs and 11 simple sequence repeats as anchor markers.The total length of the map is 724 cM, the average distance between markers is 3.6 cM.The interval mapping method was used for the QTL analyses (MapQTL 3.0 software). The theoretical significance threshold for the LOD score was 2.4.Three QTLs were detected, two on chromosome 5 and one on chromosome 6. These three QTLs explain 31% of the variation of the character.Two of them were common to two Phytophthora species. The significance and potential use of these QTLs in cocoa breeding programs will be discussed.This work was supported by CIRAD and CAOBISCO (Chocolate and biscuit industry association). (Texte intégral)
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Claims 6
Claim · model-written summary
All 202 markers mapped to ten linkage groups.
- Taxon
- Theobroma cacao
Theobroma cacaoe0 - Outcome
- linkage groupse0
- Value
- tene0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“All the markers were assigned to ten linkage groups that putatively correspond to the ten gametic chromosomes of Theobroma cacao.”
Claim · model-written summary
The map spanned 724 cM.
- Taxon
- Theobroma cacaoTheobroma cacaot0
- Outcome
- length of the mape0
- Value
- 724 cMe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The total length of the map is 724 cM, the average distance between markers is 3.6 cM.”
t0“Theobroma cacao”
Claim · model-written summary
Mean marker spacing was 3.6 cM.
- Taxon
- Theobroma cacaoTheobroma cacaot0
- Outcome
- average distance between markerse0
- Value
- 3.6 cMe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The total length of the map is 724 cM, the average distance between markers is 3.6 cM.”
t0“Theobroma cacao”
Claim · model-written summary
Three resistance QTL were found, two on chromosome 5 and one on chromosome 6.
- Taxon
- Theobroma cacaoTheobroma cacaot0
- Outcome
- QTLse0
- Value
- Threee0
- Qualifier
- two on chromosome 5 and one on chromosome 6e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Three QTLs were detected, two on chromosome 5 and one on chromosome 6.”
t0“Theobroma cacao”
Claim · model-written summary
These QTL explained 31% of trait variation.
- Taxon
- Theobroma cacaoTheobroma cacaot0
- Outcome
- variation of the charactere0
- Value
- 31%e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“These three QTLs explain 31% of the variation of the character.”
t0“Theobroma cacao”
Claim · model-written summary
Two QTL were shared between two Phytophthora species.
- Taxon
- Theobroma cacaoTheobroma cacaot0
- Outcome
- common to two Phytophthora speciese0
- Value
- Twoe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Two of them were common to two Phytophthora species.”
t0“Theobroma cacao”