AbstractsBiology & Animal Science

Development of molecular markers linked to genes of important agronomic traits for marker-assisted selection in lupin (Lupinus angustifolius L.) breeding

by Xin Li

Institution: University of Western Australia
Degree: PhD
Year: 2012
Keywords: Marker-assisted selection; MALDI-TOF MS; Genetic linkage; Lupinus angustifolius; Sequence-specific marker; Seed storage protein; MFLP fingerprinting; Narrow-leafed lupin
Record ID: 1063914
Full text PDF: http://repository.uwa.edu.au:80/R/?func=dbin-jump-full&object_id=33844&local_base=GEN01-INS01


[Truncated abstract] Narrow-leafed lupin (Lupinus angustifolius L.) is a recently domesticated commercial crop in Australia with a narrow gene pool. To broaden the genetic bases of domesticated commercial cultivars of narrow-leafed lupin, wild accessions are used as parents in lupin breeding. Most domestication genes, such as the low alkaloid gene iucundus, seed coat permeability gene mollis and reduced pod shattering genes tardus and lentus, are recessive. These recessive genes are difficult to be selected among the progenies from wild x domesticated (WxD) crosses by conventional breeding method, where molecular marker-assisted selection (MAS) is highly desirable. An F8 recombinant inbred line (RIL) population derived from a WxD cross was established by the Department of Agriculture and Food, Western Australia. The female parent was 83A:476, a sister line of L. angustifolius cv. Wonga. The pollen donor parent was P27255, originally collected from a natural population in Morocco. The parents together with 115 RILs were subjected to DNA fingerprinting using MFLP (microsatellite-anchored fragment length polymorphisms) to efficiently generate DNA polymorphisms. Experiments were set up based on a newly developed marker generating strategy by incorporating representative cultivars and wild types at the initial candidate marker identification stage for the identification of best candidate markers with highest matching rate between phenotypes of the targeted gene and the marker genotypes. In order to assess and confirm the established markers for applicability on a wide range of germplasm for MAS in lupin breeding, validation tests were further conducted on all the 25 commercial cultivars released in Australia and 125 accessions of the lupin core collection before the marker was finally judged on its suitability. In this study, four simple PCR-based co-dominant markers were successfully developed which can be widely used in narrow-leafed lupin breeding for selection of target traits. (1) Marker IucLi is 0.9 centiMorgan (cM) from the low alkaloid gene iucundus. The accuracy between marker genotype and phenotype is 100% in the 25 cultivars and 86.4% among the 125 lupin lines in core collection, which promised a broad application for selection of ‘sweet’ individuals; (2) Marker MoLi was co-segregating with the mollis gene by testing on the segregating F8 RIL population. Although the marker showed ‘0’ cM to mollis gene calculated on the F8 population containing 115 RILs, the real gene sequence of the mollis gene remains unknown. Validation tests showed that the banding pattern of marker MoLi is consistent with all the 25 historical and current commercial cultivars released in Australia, and is consistent with mollis genotypes on 119 out of the 125 accessions in the narrow-leafed lupin core collection. Marker MoLi provides a cost-effective way to select the mollis gene on a wide range of WxD crosses in lupin breeding; (3) Marker TaLi was located at a distance of 1.4cM from the tardus gene. Validation of marker TaLi found a…