title: Flowering time adaption in Swedish landrace pea (Pisum sativum L.).
abstract: Cultivated crops have repeatedly faced new climatic conditions while spreading from their site of origin. In Sweden, at the northernmost fringe of Europe, extreme conditions with temperature-limited growth seasons and long days require specific adaptation. Pea (Pisum sativum L.) has been cultivated in Sweden for millennia, allowing for adaptation to the local environmental conditions to develop. To study such adaptation, 15 Swedish pea landraces were chosen alongside nine European landraces, seven cultivars and three wild accessions. Number of days to flowering (DTF) and other traits were measured and the diversity of the flowering time genes HIGH RESPONSE TO PHOTOPERIOD (HR), LATE FLOWERING (LF) and STERILE NODES (SN) was assessed. Furthermore, the expression profiles of LF and SN were obtained.
  
  
  
  DTF was positively correlated with the length of growing season at the site of origin (GSO) of the Swedish landraces. Alleles at the HR locus were significantly associated with DTF with an average difference of 15.43 days between the two detected haplotypes. LF expression was found to have a significant effect on DTF when analysed on its own, but not when HR haplotype was added to the model. HR haplotype and GSO together explained the most of the detected variation in DTF (49.6 %).
  
  
  
  We show local adaptation of DTF, primarily in the northernmost accessions, and links between genetic diversity and diversity in DTF. The links between GSO and genetic diversity of the genes are less clear-cut and flowering time adaptation seems to have a complex genetic background.
authors: IFM-Biology, Linköping University, SE-581 83, Linköping, Sweden.
authors: Tytti
authors: T
authors: Vanhala
authors: Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway.
authors: Kjersti R
authors: KR
authors: Normann
authors: IFM-Biology, Linköping University, SE-581 83, Linköping, Sweden.
authors: Maria
authors: M
authors: Lundström
authors: School of Biological Sciences, University of Tasmania, Hobart, TAS, 7001, Australia.
authors: James L
authors: JL
authors: Weller
authors: IFM-Biology, Linköping University, SE-581 83, Linköping, Sweden.|Nordiska museet - Swedish Museum of Cultural History, SE-643 98, Julita, Sweden.
authors: Matti W
authors: MW
authors: Leino
authors: IFM-Biology, Linköping University, SE-581 83, Linköping, Sweden. Jenny.Hagenblad@liu.se.|Department of Biology, Norwegian University of Science and Technology, Trondheim, Norway. Jenny.Hagenblad@liu.se.
authors: Jenny
authors: 0000-0002-9850-5546
authors: J
authors: Hagenblad
mesh_terms: D000220:Adaptation, Biological / Q000235:genetics*; D005075:Biological Evolution; D035264:Flowers / Q000235:genetics*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D056726:Genetic Association Studies; D014644:Genetic Variation; D018532:Pisum sativum / Q000235:genetics*; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D013548:Sweden
keywords: Crop evolution; HIGH RESPONSE TO PHOTOPERIOD (HR); LATE FLOWERING (LF); Legumes; Local adaptation; STERILE NODES (SN)