title: SNP-Based Linkage Mapping for Validation of QTLs for Resistance to Ascochyta Blight in Lentil.
abstract: Lentil (Lens culinarisMedik.) is a self-pollinating, diploid, annual, cool-season, food legume crop that is cultivated throughout the world. Ascochyta blight (AB), caused byAscochyta lentisVassilievsky, is an economically important and widespread disease of lentil. Development of cultivars with high levels of durable resistance provides an environmentally acceptable and economically feasible method for AB control. A detailed understanding of the genetic basis of AB resistance is hence highly desirable, in order to obtain insight into the number and influence of resistance genes. Genetic linkage maps based on single nucleotide polymorphisms (SNP) and simple sequence repeat (SSR) markers have been developed from three recombinant inbred line (RIL) populations. The IH × NF map contained 460 loci across 1461.6 cM, while the IH × DIG map contained 329 loci across 1302.5 cM and the third map, NF × DIG contained 330 loci across 1914.1 cM. Data from these maps were combined with a map from a previously published study through use of bridging markers to generate a consensus linkage map containing 689 loci distributed across seven linkage groups (LGs), with a cumulative length of 2429.61 cM at an average density of one marker per 3.5 cM. Trait dissection of AB resistance was performed for the RIL populations, identifying totals of two and three quantitative trait loci (QTLs) explaining 52 and 69% of phenotypic variation for resistance to infection in the IH × DIG and IH × NF populations, respectively. Presence of common markers in the vicinity of the AB_IH1- and AB_IH2.1/AB_IH2.2-containing regions on both maps supports the inference that a common genomic region is responsible for conferring resistance and is associated with the resistant parent, Indianhead. The third QTL was derived from Northfield. Evaluation of markers associated with AB resistance across a diverse lentil germplasm panel revealed that the identity of alleles associated with AB_IH1 predicted the phenotypic responses with high levels of accuracy (~86%), and therefore have the potential to be widely adopted in lentil breeding programs. The availability of RIL-based maps, a consensus map, and validated markers linked to AB resistance provide important resources for lentil improvement.
authors.affiliation: Biosciences Research, Agriculture Victoria, AgriBio, La Trobe University Bundoora, VIC, Australia.
authors.forename: Shimna
authors.initials: S
authors.lastname: Sudheesh
authors.affiliation: Biosciences Research, Agriculture Victoria Horsham, VIC, Australia.
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Rodda
authors.affiliation: South Australia Research and Development Institute, Plant Research Centre Urrbrae, SA, Australia.
authors.forename: Jenny
authors.initials: J
authors.lastname: Davidson
authors.affiliation: Biosciences Research, Agriculture Victoria Horsham, VIC, Australia.
authors.forename: Muhammad
authors.initials: M
authors.lastname: Javid
authors.affiliation: Biosciences Research, Agriculture Victoria, AgriBio, La Trobe University Bundoora, VIC, Australia.
authors.forename: Amber
authors.initials: A
authors.lastname: Stephens
authors.affiliation: Biosciences Research, Agriculture Victoria, AgriBio, La Trobe University Bundoora, VIC, Australia.
authors.forename: Anthony T
authors.initials: AT
authors.lastname: Slater
authors.affiliation: Biosciences Research, Agriculture Victoria, AgriBio, La Trobe UniversityBundoora, VIC, Australia; School of Applied Systems Biology, La Trobe UniversityBundoora, VIC, Australia.
authors.forename: Noel O I
authors.initials: NO
authors.lastname: Cogan
authors.affiliation: Biosciences Research, Agriculture Victoria, AgriBio, La Trobe UniversityBundoora, VIC, Australia; School of Applied Systems Biology, La Trobe UniversityBundoora, VIC, Australia.
authors.forename: John W
authors.initials: JW
authors.lastname: Forster
authors.affiliation: Biosciences Research, Agriculture Victoria, AgriBio, La Trobe University Bundoora, VIC, Australia.
authors.forename: Sukhjiwan
authors.initials: S
authors.lastname: Kaur
keywords: fungal disease resistance; legume; molecular breeding; pulse; single nucleotide polymorphism