title: Morphology, carbohydrate composition and vernalization response in a genetically diverse collection of Asian and European turnips (Brassica rapa subsp. rapa).
abstract: Brassica rapa displays enormous morphological diversity, with leafy vegetables, turnips and oil crops. Turnips (Brassica rapa subsp. rapa) represent one of the morphotypes, which form tubers and can be used to study the genetics underlying storage organ formation. In the present study we investigated several characteristics of an extensive turnip collection comprising 56 accessions from both Asia (mainly Japanese origin) and Europe. Population structure was calculated using data from 280 evenly distributed SNP markers over 56 turnip accessions. We studied the anatomy of turnip tubers and measured carbohydrate composition of the mature turnip tubers of a subset of the collection. The variation in 16 leaf traits, 12 tuber traits and flowering time was evaluated in five independent experiments for the entire collection. The effect of vernalization on flowering and tuber formation was also investigated. SNP marker profiling basically divided the turnip accessions into two subpopulations, with admixture, generally corresponding with geographical origin (Europe or Asia). The enlarged turnip tuber consists of both hypocotyl and root tissue, but the proportion of the two tissues differs between accessions. The ratio of sucrose to fructose and glucose differed among accessions, while generally starch content was low. The evaluated traits segregated in both subpopulations, with leaf shape, tuber colour and number of shoots per tuber explaining most variation between the two subpopulations. Vernalization resulted in reduced flowering time and smaller tubers for the Asian turnips whereas the European turnips were less affected by vernalization.
authors.affiliation: Wageningen UR Plant Breeding, Wageningen, The Netherlands.
authors.forename: Ningwen
authors.initials: N
authors.lastname: Zhang
authors.affiliation: Wageningen UR Plant Breeding, Wageningen, The Netherlands; Horticultural College, Hebei Agricultural University, Baoding, China.
authors.forename: Jianjun
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Naturalis Biodiversity Center, Leiden, The Netherlands.
authors.forename: Frederic
authors.initials: F
authors.lastname: Lens
authors.affiliation: Wageningen UR Plant Breeding, Wageningen, The Netherlands.
authors.forename: Joan
authors.initials: J
authors.lastname: de Visser
authors.affiliation: Wageningen UR Plant Breeding, Wageningen, The Netherlands.
authors.forename: Temesgen
authors.initials: T
authors.lastname: Menamo
authors.affiliation: Wageningen UR Plant Breeding, Wageningen, The Netherlands.
authors.forename: Wen
authors.initials: W
authors.lastname: Fang
authors.affiliation: Wageningen UR Plant Breeding, Wageningen, The Netherlands; State Key Laboratory of Crop Genetics and Germplasm Enhancement, Horticultural College, Nanjing Agricultural University, Nanjing, Jiangsu, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Xiao
authors.affiliation: Wageningen UR Plant Breeding, Wageningen, The Netherlands.
authors.forename: Johan
authors.initials: J
authors.lastname: Bucher
authors.affiliation: Wageningen UR Plant Breeding, Wageningen, The Netherlands.
authors.forename: Ram Kumar
authors.initials: RK
authors.lastname: Basnet
authors.affiliation: Wageningen UR Plant Breeding, Wageningen, The Netherlands.
authors.forename: Ke
authors.initials: K
authors.lastname: Lin
authors.affiliation: Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Cheng
authors.affiliation: Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing, China.
authors.forename: Xiaowu
authors.initials: X
authors.lastname: Wang
authors.affiliation: Wageningen UR Plant Breeding, Wageningen, The Netherlands.
authors.forename: Guusje
authors.initials: G
authors.lastname: Bonnema
mesh_terms: D001208:Asia; D029741:Brassica rapa / Q000033:anatomy & histology / Q000737:chemistry / Q000235:genetics*; D002241:Carbohydrates / Q000737:chemistry / Q000302:isolation & purification; D018556:Crops, Agricultural; D005060:Europe; D035264:Flowers / Q000235:genetics; D014644:Genetic Variation; D006801:Humans; D010641:Phenotype; D018515:Plant Leaves / Q000235:genetics; D018517:Plant Roots / Q000235:genetics; D040641:Quantitative Trait Loci / Q000235:genetics*
chemical_list: D002241:Carbohydrates