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ABSTRACT
Root-knot nematodes (Meloidogyne spp.) resulted significant yield losses in peppers. It has been reported that at least 10 dominant genes (N, Me1, Me2, Me3, Me4, Me5, Me6, Me7, Mech1 and Mech2) associated with resistance to Meloidogyne spp. are thought to act independently in gene-for-gene interactions in pepper. Several molecular markers were developed for these genes to be used in marker-assisted selection (MAS). The markers include N-SCAR, SCAR_B94, SCAR_CD, SCAR_PM6a, SCAR_PM6b, and SCAR_PM54. In this study, the pepper genotypes reported to carry different resistant genes against the nematodes were artificially inoculated with root-knot nematode (Meloidogyne incognita race 2) and compared via the linked molecular markers. Of all the markers tested, the SCAR_PM54 marker results were fully consistent with artificial nematode testing, correctly predicting resistant and susceptible genotypes. The results documented once again that the linked markers should be confirmed through classical testing before utilizing them in MAS.
Key words: Pepper, Root-knot nematodes, Resistance, Molecular marker.
INTRODUCTION
Root-knot nematodes (RKNs) (Meloidogyne spp.) are important pests significantly limiting world pepper production. Turkey ranks the third with 2 million tons/year pepper production in the world (31 million tons/year) (FAO, 2012). In field and other protected vegetable production areas, M. arenaria (Neal, 1889) Chitwood 1949, M. javanica (Treub, 1885) Chitwood 1949 and M. incognita (Kofoid & White, 1919) Chitwood 1949 were identified as the most common and economically important species (Sogut & Elekçioglu, 2000 and Ozarslandan & Elekçioglu, 2010). It is known that M. incognita is widespread over pepper cultivated areas. On the contrary, M. javanica was not able to propagate and damage peppers (Özarslandan & Elekçioglu, 2003). Nematicides and fumigants are commonly used to fight against RKNs in vegetable cultivated lands. Wesemael et al. (2011) reported negative impacts of these chemicals on human health and environment. Researchers also indicated that crop rotation, non-host species and resistant cultivars could be effective in diminishing root-knot nematode infections, but host status should be known to get success in nematode control. Resistant pepper lines may restrict the reproduction of M. incognita and be effective in control of the nematode. Therefore, resistant lines and cultivars are used in integrated pest management programs together with solarization, crop rotation and other control procedures (Ozarslandan et al., 2015).
There are different non-allelic nematode resistance genes...