Breeding Science
Online ISSN : 1347-3735
Print ISSN : 1344-7610
ISSN-L : 1344-7610
Research paper
QTL Analysis for Resistance to Phytophthora Blight (Phytophthora capsici Leon.) Using an Intraspecific Doubled-Haploid Population of Capsicum annuum
Toru SugitaKazunori YamaguchiTetsuji KinoshitaKenichi YujiYukiyo SugimuraRyutaro NagataShinji KawasakiAtsushi Todoroki
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JOURNAL FREE ACCESS

2006 Volume 56 Issue 2 Pages 137-145

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Abstract

A doubled-haploid (DH) population (n = 176) obtained by anther culture of an F1 hybrid between a line susceptible to Phytophthora capsici ‘K9-11’ (Capsicum annuum L.) and a line resistant to P. capsici ‘AC2258’ (C. annuum L.) was inoculated with P. capsici. QTL analysis of the resistance was performed using a linkage map consisting of 16 linkage groups (LGs), covering a total distance of 1100.5 cM. Three QTLs were detected on LG1, LG6 and LG7. The QTL with the highest LOD score, detected on LG7, explained 82.7% of the phenotypic variance with a LOD score of 67.02. This QTL was designated as Phyt-1. The nearest marker was an AFLP marker, M10E3-6. The second QTL, designated as Phyt-2, was found on LG1. It explained 6.4% of the phenotypic variance with a LOD score of 2.54. The nearest RAPD marker was RP13-1. The other QTL, designated as Phyt-3, which was found on LG6, explained 5.6% of the phenotypic variance with a LOD score of 2.20. The nearest AFLP marker was M9E3-11. It was confirmed that the lines with a high resistance could be efficiently selected by using two markers, M10E3-6 and RP13-1, simultaneously. The presence of both Phyt-1 and Phyt-2 under homozygous conditions may enable to breed resistant cultivars of sweet pepper. The molecular markers identified in the present study could be useful for marker-assisted selection (MAS) in order to breed sweet pepper cultivars with a high resistance to P. capsici using ‘AC2258’ as a source of resistance genes.

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© 2006 by JAPANESE SOCIETY OF BREEDING
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