RETRACTED ARTICLE: A reexamination of molecular markers for use in marker-assisted breeding in tomato

Abstract

Molecular markers have been used for identification and mapping of genes and QTLs for numerous agriculturally important traits in tomato, including resistance/tolerance to biotic and abiotic stresses and fruit-and flower-related characteristics. However, the extent to which markers have been utilized in tomato breeding programs has not been clearly determined. A review of the literature indicated that the utility of most markers for use in tomato breeding programs have not been verified. Many markers are not validated across tomato genotypes or are not polymorphic within tomato breeding populations. In this study, we examined the utility of available markers for several major disease resistance traits in tomato by testing them in a number of breeding lines and commercial cultivars with known resistance/susceptibility responses. While several markers were validated, others needed PCR optimization for successful amplifications or were not informative in the genotypes used. Specifically, of the 37 markers examined 19 (*51%) were informative, including markers for resistance to Fusarium wilt, late blight, bacterial wilt, tomato mosaic virus, tomato spotted wilt virus, and root knot nematodes. It appears that many of the available markers may need to be further refined or examined for trait association and presence of polymorphism in breeding lines and populations. However, with recent advances in tomato sequencing, it is becoming increasingly possible to develop more informative markers to accelerate the use of MAS in tomato breeding.

Novel molecular marker associated with Tm2a gene conferring resistance to tomato mosaic virus in tomato

“…The study identified a novel PCR‐based molecular marker NCTm‐019 using the published sequence of the Tm2 a locus. This finding has overcome the previously unreproducible results using several molecular markers (Panthee and Foolad ). One explanation for the failure to validate the findings of that previous study is that all of the reported molecular markers were from flanking regions (Dax et al.…”

“…). However, these markers were not useful when evaluated with independent genetic materials (Panthee and Foolad ). The lack of utility of these markers might be attributed to the position of the markers on the genome of tomato, recombination between the markers and target genes, genetic background or population specificity when the markers were developed.…”

“…Based on this information, molecular markers have been developed and employed in different tomato breeding programmes (Dax et al 1994, 1998, Ohmori et al 1995, 1996, Sobir et al 2000. However, these markers were not useful when evaluated with independent genetic materials (Panthee and Foolad 2012). The lack of utility of these markers might be attributed to the position of the markers on the genome of tomato, recombination between the markers and target genes, genetic background or population specificity when the markers were developed.…”

Quality selection and genetic diversity of Tunisian durum wheat varieties using SSR markers

“…We can use them in Tunisian breeding programs associated with interesting subunits of gliadin and glutenin (e.g., Gli-γ-45 and Gli-γ-42 are respectively markers of good and poor gluten strength) (MARTÍNEZ et al 2005: EDWARDS et al 2007). On the other hand, the failure of some markers to select specific traits could be due to various reasons, including the absence of complementary genomic sequences with the primers used, breakdown of linkages between markers and genes, and differences and artefacts in PCR conditions (PANTHEE et al 2012). Molecular markers associated with genes or QTLs underlying many complex quality traits in wheat have been identified.…”

Tomato Spotted Wilt Virus-resistant Fresh-market Tomato Breeding Lines: NC 58S, NC 123S, NC 127S, and NC 132S

“…Single plant selections of all of the lines were made through the F 5 generation, and bulking of seed of the individual selections was done in subsequent generations. Repeated testing of the four lines for molecular markers linked to the Sw-5 (Robbins et al, 2010), I-3, and Mi genes has been conducted (Panthee and Foolad, 2012).…”