ABSTRACT
One hundred and eighty-three recombinant inbred lines from the cross between GH06 and P174 were used for genetic analysis of seed germination rate and physiological trait analysis of Brassica napus L. Composite interval mapping (CIM) was applied to identify QTL associated with seed germination rate (GR) of the seeds that stored for two years (STY), one year (SOY), and fresh seeds (FS), respectively. The activity of lipases, seed conductivity, reducing sugar content, total sugar content, and root vitality of STY and FS were investigated. The QTL for seed GR of various stored seeds were different. Three QTLs for STY were detected on the linkage group (LG) 9, 14, and 17. Two QTL for SOY were mined on LG 5 and 9. Two QTLs for FS were detected on LG 4 and 18. The germination rate of seeds from three years was significantly different, and the QTL of GR was not identical, which indicated that the seed germination was controlled by many loci. Furthermore, the seed germination rate was negatively correlated with seed conductivity, which means that measurement of seed conductivity can be used to estimate GR, and the study of conductivity is important for GR research.
Subject(s)
Brassica napus/genetics , Germination/genetics , Quantitative Trait Loci/genetics , Brassica napus/physiology , Germination/physiology , Physiological Phenomena , Seeds/geneticsABSTRACT
Yellow seed is one of the most important traits of Brassica napus L. Efficient selection of the yellow-seed trait is one of the most important objectives in oilseed rape breeding. Two recombinant inbred line (RIL) populations (RIL-1 and RIL-2) were analyzed for 2 years at 2 locations. Four hundred and twenty SSR, RAPD, and SRAP marker loci covering 1744 cM were mapped in 26 linkage groups of RIL-1, while 265 loci covering 1135 cM were mapped in 20 linkage groups of RIL-2. A total of 19 QTLs were detected in the 2 populations. A major QTL was detected adjacent to the same marker (EM11ME20/200) in both maps in both years. This major QTL could explain 53.71%, 39.34%, 42.42%, 30.18%, 24.86%, and 15.08% of phenotypic variation in 6 combinations (location x year x population). BLASTn analysis of the sequences of the markers flanking the major QTL revealed that the homologous region corresponding to this major QTL was anchored between genes At5g44440 and At5g49640 of Arabidopsis thaliana chromosome 5 (At C5). Based on comparative genomic analysis, the bifunctional gene TT10 is nearest to the homologue of EM11ME20/200 on At C5 and can be considered an important candidate gene for the major QTL identified here. Besides providing an effective strategy for marker-assisted selection of the yellow-seed trait in B. napus, our results also provide important clues for cloning of the candidate gene corresponding to this major QTL.
Subject(s)
Brassica napus/genetics , Quantitative Trait Loci , Recombination, Genetic , Seeds/genetics , Chromosome Mapping , Color , Environment , Genetic Markers , SyntenyABSTRACT
The development of yellow-seeded varieties of Brassica napus for improving the oilseed quality characteristics of lower fiber content and higher protein and oil content has been a major focus of breeding researches worldwide in recent years. With the black-seeded 'Youyan 2' as male and the yellow-seeded GH06 as female parents respectively, F2 population of 132 individuals were obtained. A linkage map was constructed with 164 markers including 125 AFLP, 37 SSR, 1 RAPD and 1 SCAR markers distributed over 19 linkage groups covering approximately 2 549.8 cM with an average spacing of 15.55 cM. Two loci located on the 5th and 19th group were detected for the trait of seed coat color based on the linkage group using multiple interval mapping method and explained 46% and 30.9% of the phenotypic variation, respectively.
Subject(s)
Brassica napus/genetics , Chromosomes, Plant/genetics , Quantitative Trait Loci , Seeds/genetics , Amplified Fragment Length Polymorphism Analysis , Chromosome Mapping/methods , Crosses, Genetic , Genetic Linkage , Genetic Markers/genetics , Microsatellite Repeats/genetics , Pigmentation/genetics , Random Amplified Polymorphic DNA TechniqueABSTRACT
The study on genetic relationship among A, B and C genomes in Brassica genera has gained prodigious development, which revealed that the relationship between A and C genome was more closer than that of A and B, B and C genome. The results of comparative genomics showed that A, B and C genomes were all originated from a common ancestral genome. A lot of chromosome variations were taken place in the evolution of Brassica genomes, such as duplication, deletion and rearrangement, resulting in the difference of genomes. At last, the genetic relationship between Brassica genera and Arabidopsis thaliana was summarized.
