Phytophthora capsici an Oomycete pathogen is a major challenge to the pepper (Capsicum spp.) production around the world. Control measures are proved ineffective, so breeding resistant cultivars are the most promising strategy against the pathogen. Resistance against P. capsici is governed by quantitative trait loci (QTL). According to previous studies on QTL detection, the QTL on pepper chromosome 5 is a major contributor to resistance. In this study, to exploit the involvement of this QTL and identify its contributing genes, the F2 population derived from a cross between ECW30R and CM334 was inoculated with a medium virulence P. capsici strain JHAI1-7 zoospores at the 6-8 leaf stage. Composite interval mapping revealed two major QTLs; QTL5-1 from 7 days post inoculation (dpi) and QTL5-2 from 16 dpi on chromosome 5. To characterize and detect interactions of the two QTLs, near isogenic lines (NIL) were constructed by crossing Tean and recombinant inbred line (RIL) derived from a cross between YCM334 and Tean. RILs were screened with P. capsici strain MY-1 and resistant lines were selected. Among the resistance RILs most closely related to Tean were selected using AFLP and SSR genotyping data. These RILs were named as YT39-2 and YT143-2. To develop more advanced NILs, two rounds of marker-assisted backcrossing were done using a high-throughput SNP genotyping system (EPI Fluidigm, USA). Among the NILs derived from YT39-2, YT39-2-64 contains only QTL5-1 whereas YT39-2-61 and YT39-2-69 were identified to have both QTLs. On the other hand, YT143-2-55-7 with the highest Tean genetic background contains QTL5-1 only. In the next step, the 3 different NILs having QTL5-1, QTL5-2 individually and both QTLs will be identified. Furthermore, phenotyping and fine mapping will be done for the analysis of individual and interaction effects of QTLs.

Pepper mottle virus (PepMoV) is frequently occurring virus in pepper field. PepMoV infected plants show symptoms including mosaic leaf, distortion of foliage and fruit deformation. The dominant gene Pvr7 from Capsicum annuum ‘9093’ confers resistance to PepMoV. Previous research reveals that Pvr7 is located in 10 chromosome and linked to the dominant potyvirus resistance gene Pvr4 and Tomato spotted wilt virus (TSWV) resistance gene Tsw. To identify the Pvr7 gene, we constructed an intraspecific F2 mapping population from a cross between C. annuum ‘9093’ (PepMov resistant) and C. annuum ‘Jejujaerae’ (PepMoV susceptible). Resistance of F2 plants were screened with green flouorescent protein (GFP) tagged PepMoV. Genomic DNA was extracted from F2 individuals and markers were developed using C.annuum ‘CM334’ whole genome sequence (WGS). Several single nucleotide polymorphism (SNP) markers that were co-segregated with Pvr7 were developed. We are expecting that this Pvr7 SNP marker can be used to breeding PepMoV resistant cultivars and fine mapping of Pvr7.