A molecular linkage map of tomato based on a cross between Lycopersicon esculentum andL. pimpinellifolium and its comparison with other molecular maps of tomato

Abstract

The wild species related to the cultivated tomato, Lycopersicon esculentum Mill., are a rich source of useful genes for germplasm improvement and varietal development. Characterization and utilization of exotic germplasm can be accelerated by the use of molecular linkage maps. Recently, we have identified an accession (LA722) within L. pimpinellifolium Jusl., a closely-related, red-fruited wild species of tomato, which exhibits a number of desirable agricultural characteristics including salt tolerance, disease resistance, and high fruit quality. The limited DNA marker polymorphism between L. esculentum and L. pimpinellifolium, however, restricts the use of the high-density molecular map of tomato, which was previously constructed based on a cross between L. esculentum and L. pennellii Corr., for marker-assisted identification and utilization of useful genes in LA722. To overcome this problem, we have constructed a linkage map based on restriction fragment length polymorphisms (RFLPs) which were identified between LA722 and a fresh-market tomato breeding line (NC84173). The mapping population (consisting of 119 BC 1 individuals) was genotyped for 151 RFLP markers, including 17 germination related and 2 potassium transporter cDNAs. The DNA markers spanned approximately 1192 cM of the tomato genome with an average distance of 7.9 cM between markers. The length of the map and the linear order of the markers were in good agreement with those of the previously published molecular maps of tomato, however, there were considerable differences in the distribution of recombinations along the chromosomes. Comparison of all seven published molecular maps of tomato, which were constructed based on different inter-and intraspecific crosses, indicated that some chromosomal regions were more stable than others in terms of the frequency of recombinations. Similarities and differences among tomato molecular maps are discussed in relation to phylogenetic relationships between parents of the mapping populations. In comparison, a L. esculentum × L. pimpinellifolium map should be more useful than other interspecific maps for marker-assisted exploitation of genetic variation that exists within L. pimpinellifolium or L. esculentum; the latter is because of the extensive introgression of genes from L. pimpinellifolium into L. esculentum, which occurred over time by natural means or through plant breeding. 103Résumé : Les espèces sauvages apparentées à la tomate cultivée, Lycopersicon esculentum Mill., constituent un riche réservoir de gènes utiles pour l'amélioration du germoplasme et la création variétale. La caractérisation et l'exploitation du germoplasme exotique peut être accélérée par l'emploi de cartes génétiques composées de marqueurs moléculaires. Récemment, les auteurs ont identifié une accession (LA722) intéressante parmi le L. pimpinellifolium Jusl., une espèce sauvage à fruits rouges qui est très apparentée à la tomate. Cette accession possède plusieurs caractéristiques avantageuses dont la tolérance à la salinité, la résist...

QTL identification for early blight resistance (Alternaria solani) in a Solanum lycopersicum × S. arcanum cross

“…Less skewed segregation (8-10%) was exhibited in crosses with S. pimpinellifolium (syn. L. pimpinellifolium), a species closely related with the cultivated tomato (Grandillo and Tanksley 1996;Chen and Foolad 1999). A distortion rate (55%) similar to our result was previously reported by Van Heusden et al (1999) using a different subset of F2 progeny from the same cross with S. arcanum LA2157.…”

Development and characterization of tomato SSR markers from genomic sequences of anchored BAC clones on chromosome 6

“…Paran et al (1995) reported that 73% markers in a RIL population derived from S. lycopersicum 9 S. cheesmanii cross showed significant segregation distortion in favor of S. lycopersicum alleles. Furthermore, high level of skewed segregation has been observed for markers on chromosome 6 even in other mapping populations involving various interspecific crosses of tomato such as S. lycopersicum 9 S. pimpinellifolium (Grandillo and Tanksley 1996;Chen and Foolad 1999;Sharma et al 2008) and S. lycopersicum 9 S. hirsutum (Bernacchi and Tanksley 1997;Zhang et al 2002). This was mainly attributed to the presence of the self-pruning (sp) locus on chromosome 6, near the RFLP marker TG279 (Fulton et al 1997).…”

Evaluation of fruit quality traits of traditional varieties of tomato (Solanum lycopersicum) grown in Tunisia

“…Estimates of SS contents of the commercial cultivars of tomato range between 4.6 (mostly fresh tomato) and 6.3% (mostly for processing) of fresh weight. However, accessions have been identified within related wild species of tomato, including Lycopersicon pimpinellifolium, Lycopersicon chmielewskii and Lycopersicon cheesmanii, with much higher concentrations (9 to 15%) of SS (Chen and Foolad, 1999). Titratable acidity, pH, fruit firmness are important fruit quality characteristics of tomato.…”