Evaluation of yield and agronomic traits and their genetic variation in 488 global collections of Brassica napus L.

Yield is one of the most important traits in Brassica napus breeding programs. Quantitative trait loci (QTLs) for yield-related traits based on genetic mapping would help breeders to develop high-yield cultivars. In this study, a genetic linkage map of B. napus, containing 142 sequence-related amplified polymorphism (SRAP) markers, 163 functional markers, 160 simple sequence repeat (SSR) markers, and 117 amplified fragment length polymorphism (AFLP) markers, was constructed in an F2 population of 184 individuals resulting from the cross SI-1300 × Eagle. This map covered 2054.51 cM with an average marker interval of 3.53 cM. Subsequently, QTLs were detected for 12 yield-related traits in Wuhan and Jingmen. In total, 133 QTLs were identified, including 14 consistent ones across the 2 locations. Fifteen of 20 linkage groups (LGs) were found to have QTLs for the 12 traits investigated, and most of the QTLs were clustered, especially on LGs N2 and N7, where similar QTL positions were identified for multiple traits. Eight of 10 QTLs for yield per plant (YP) were also associated with number of seeds per silique (SS), number of siliques per plant (SP), and/or 1000-seed weight (SW). In addition, 45 functional markers involved in 39 expressed sequence tags (ESTs) were linked to the QTLs of 12 traits. The present results may serve as a valuable basis for further molecular dissection of agronomic traits in B. napus, and the markers related to QTLs may offer promising possible makers for marker assisted selection.

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Linkage Analysis of Molecular Markers and Quantitative Trait Loci in Populations of Inbred Backcross Lines of Brassica napus L.

Genetics ◽

10.1093/genetics/153.2.949 ◽

1999 ◽

Vol 153 (2) ◽

pp. 949-964 ◽

Cited By ~ 2

Author(s):

David V Butruille ◽

Raymond P Guries ◽

Thomas C Osborn

Keyword(s):

Genetic Variation ◽

Brassica Napus ◽

Quantitative Trait Loci ◽

Qtl Analysis ◽

Quantitative Trait ◽

Agronomic Traits ◽

Pedigree Structure ◽

Inbred Backcross Lines ◽

Trait Loci ◽

Inbred Backcross

Abstract Backcross populations are often used to study quantitative trait loci (QTL) after they are initially discovered in balanced populations, such as F2, BC1, or recombinant inbreds. While the latter are more powerful for mapping marker loci, the former have the reduced background genetic variation necessary for more precise estimation of QTL effects. Many populations of inbred backcross lines (IBLs) have been developed in plant and animal systems to permit simultaneous study and dissection of quantitative genetic variation introgressed from one source to another. Such populations have a genetic structure that can be used for linkage estimation and discovery of QTL. In this study, four populations of IBLs of oilseed Brassica napus were developed and analyzed to map genomic regions from the donor parent (a winter-type cultivar) that affect agronomic traits in spring-type inbreds and hybrids. Restriction fragment length polymorphisms (RFLPs) identified among the IBLs were used to calculate two-point recombination fractions and LOD scores through grid searches. This information allowed the enrichment of a composite genetic map of B. napus with 72 new RFLP loci. The selfed and hybrid progenies of the IBLs were evaluated during two growing seasons for several agronomic traits. Both pedigree structure and map information were incorporated into the QTL analysis by using a regression approach. The number of QTL detected for each trait and the number of effective factors calculated by using biometrical methods were of similar magnitude. Populations of IBLs were shown to be valuable for both marker mapping and QTL analysis.

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Effects of simulated hail damage manifested by stem cutoff on seed yield and agronomic traits in Brassica napus L.

Journal of Crop Improvement ◽

10.1080/15427528.2020.1737295 ◽

2020 ◽

Vol 34 (4) ◽

pp. 470-485

Author(s):

Jonathan Vollmer ◽

Mukhlesur Rahman

Keyword(s):

Brassica Napus ◽

Seed Yield ◽

Agronomic Traits ◽

Brassica Napus L ◽

Hail Damage

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Fine mapping of the QTL cqSPDA2 for chlorophyll content in Brassica napus L.

BMC Plant Biology ◽

10.1186/s12870-020-02710-y ◽

2020 ◽

Vol 20 (1) ◽

Author(s):

Jingxiu Ye ◽

Haidong Liu ◽

Zhi Zhao ◽

Liang Xu ◽

Kaixiang Li ◽

...

Keyword(s):

Brassica Napus ◽

Chlorophyll Content ◽

Fine Mapping ◽

Agronomic Traits ◽

Economic Value ◽

Chlorophyll Synthesis ◽

Brassica Napus L ◽

Oil Crops ◽

Initial Location ◽

Dh Lines

Abstract Background Chlorophyll is the most important factor enabling plants to absorb, transfer and transform light energy and plays an important role in yield formation. Brassica napus is one of the most important oil crops. Breeding Brassica napus for high light efficiency by improving photosynthetic efficiency has considerable social and economic value. In Brassica napus, there have been studies of the initial location of chlorophyll in seed embryos and pericarps, but there are few reports on the fine mapping of chlorophyll QTLs. We constructed near-isogenic lines (NIL), fine-mapped a chlorophyll locus, and evaluated the effect of this dominant locus on agronomic traits. Results The cqSPDA2 locus was mapped to an interval of 21.87–22.91 Mb on the chromosome A02 of Brassica napus using doubled haploid (DH) lines. To fine-map cqSPDA2, we built NIL and designed Indel primers covering the mapping interval. The 469 individuals in the BC3F2 population were analyzed using these indel primers. Among these indel primers, 15 could narrow the mapping interval to 188 kb between Indel3 and Indel15. Next, 16 indel primers and 19 SSR primers were designed within the new narrower mapping interval, and 5 of the primer-amplified fragments were found to be polymorphic and tightly linked to the cqSPDA2 locus in the BC4F2 population. The mapping interval was narrowed to 152 kb on A02 between SSR2 and Indel15. By gene expression analysis, we found three annotated genes in the mapping interval, including BnaA02g30260D, BnaA02g30290D and BnaA02g30310D, which may be responsible for chlorophyll synthesis. Conclusions The locus cqSPDA2, a dominant QTL for chlorophyll content in Brassica napus, was fine-mapped to a 21.89–22.04 Mb interval on A02. Three annotated genes (BnaA02g30260D, BnaA02g30290D and BnaA02g30310D) that may be responsible for chlorophyll synthesis were found.

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