title: A new polymorphism on chromosome 6 associated with bolting tendency in sugar beet.
abstract: BACKGROUND
  Premature flowering or bolting is an undesirable characteristic that causes severe sugar yield losses and interferes with harvesting. Vernalization is a prerequisite for the floral induction, achieved by exposure to low temperatures for 10-14 weeks. This process is also controlled by other environmental factors, such as long daylight photoperiods and a combination of genetic factors. The objective of this study was the identification of new genetic polymorphisms linked to bolting tendency in sugar beet.
  
  
  RESULTS
  Two pollinators characterized by low and high bolting tendency were subjected to RAD-sequencing in order to detect discriminating SNPs between lines. 6,324 putative SNPs were identified. Of these, 192 were genotyped in a set of 19 pollinators, each comprising bolted and non-bolted individuals, for a total of 987 samples. Among the 192 candidate SNPs, the strongest overall association was found for SNP183 on chromosome 6 (p-value = 1.246 10(-13)). The association between SNP183 and bolting tendency was then confirmed in an independent population of 730 plants from 11 breeding lines (p-value = 0.0061). SNP183 is located in the intron of Bv_22330_orky, a sugar beet homolog of a matrix metalloproteinase (MMP) gene that could be implied in flowering in Arabidopsis thaliana.
  
  
  CONCLUSIONS
  Our data support a significant association between an intronic SNP in the MMP gene located on chromosome 6 and the regulation of bolting tendency in sugar beet. The newly identified locus supports the polygenic nature of flowering control. The associated marker can be used to design SNP panels for the discrimination of bolters and non-bolters, to be used in sugar beet breeding programs for the development of improved germplasm with low bolting tendency.
authors.affiliation: DAFNAE, Dipartimento di Agronomia Animali Alimenti Risorse Naturali e Ambiente, Università degli Studi di Padova, viale dell'Università 16, 35020, Legnaro, PD, Italy. chiarabr87@yahoo.it.
authors.forename: Chiara
authors.initials: C
authors.lastname: Broccanello
authors.affiliation: DAFNAE, Dipartimento di Agronomia Animali Alimenti Risorse Naturali e Ambiente, Università degli Studi di Padova, viale dell'Università 16, 35020, Legnaro, PD, Italy. stevanato@unipd.it.
authors.forename: Piergiorgio
authors.initials: P
authors.lastname: Stevanato
authors.affiliation: FPTP, Fondazione Parco Tecnologico Padano, viale Einstein, Loc. Cascina Codazza, 26900, Lodi, Italy. stevanato@unipd.it.
authors.forename: Filippo
authors.initials: F
authors.lastname: Biscarini
authors.affiliation: Department of Viticulture and Enology, University of California, Davis, 2146 RMI North Building Davis, Davis, CA, 95616, USA. dacantu@ucdavis.edu.
authors.forename: Dario
authors.initials: D
authors.lastname: Cantu
authors.affiliation: DAFNAE, Dipartimento di Agronomia Animali Alimenti Risorse Naturali e Ambiente, Università degli Studi di Padova, viale dell'Università 16, 35020, Legnaro, PD, Italy. massimo.saccomani@unipd.it.
authors.forename: Massimo
authors.initials: M
authors.lastname: Saccomani
mesh_terms: D027461:Beta vulgaris / Q000235:genetics* / Q000254:growth & development*; D032461:Chromosomes, Plant; D018744:DNA, Plant; D007438:Introns; D020782:Matrix Metalloproteinases / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide
chemical_list: D018744:DNA, Plant; D020782:Matrix Metalloproteinases