title: Mapping QTLs for root morphological traits in Brassica rapa L. based on AFLP and RAPD markers.
abstract: Root growth and thickening plays a key role in the final productivity and even the quality of storage roots in root crops. This study was conducted to identify and map quantitative trait loci (QTLs) affecting root morphological traits in Brassica rapa by using molecular markers. An F2 population was developed from a cross between Chinese cabbage (Brassica rapa ssp. chinensis) and turnip (B. rapa ssp. rapifera), which differed greatly in root characters. A genetic map covering 1837.1 cM, with 192 marker loci and 11 linkage groups, was constructed by using this F2 population. The F3 families derived from F2 plants were grown in the field and evaluated for taproot traits (thickness, length, and weight). QTL analysis via simple interval mapping detected 18 QTLs for the 3 root traits, including 7 QTLs for taproot thickness, 5 QTLs for taproot length, and 6 QTLs for taproot weight. Individually, the QTLs accounted for 8.4-27.4% of the phenotypic variation. The 2 major QTLs, qTRT4b for taproot thickness and qTRW4 for taproot weight, explained 27.4% and 24.8% of the total phenotypic variance, respectively. The QTLs for root traits, firstly detected in Brassica crops, may provide a basis for marker-assisted selection to improve productivity in root-crop breeding.
authors.affiliation: Key Laboratory of Horticultural Plant Growth, Development and Biotechnology, Department of Horticulture, Zhejiang University, Kaixuan Road 268, Hangzhou 310029, P.R. China. glu@zju.edu.cn
authors.forename: Gang
authors.initials: G
authors.lastname: Lu
authors.forename: Jiashu
authors.initials: J
authors.lastname: Cao
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Yu
authors.forename: Xun
authors.initials: X
authors.lastname: Xiang
authors.forename: Hang
authors.initials: H
authors.lastname: Chen
mesh_terms: D054458:Amplified Fragment Length Polymorphism Analysis; D029741:Brassica rapa / Q000033:anatomy & histology / Q000235:genetics*; D002874:Chromosome Mapping; D005819:Genetic Markers; D018517:Plant Roots / Q000033:anatomy & histology / Q000235:genetics*; D040641:Quantitative Trait Loci / Q000235:genetics*; D019105:Random Amplified Polymorphic DNA Technique
chemical_list: D005819:Genetic Markers