大豆苗期耐盐性的遗传及QTL定位分析

利用亲本为科丰1号和南农1138—2的重组自交系群体NJRIKY进行大豆苗期耐盐性的遗传及QTL定位分析。以每个家系的平均存活时间为耐盐指标,采用主基因＋多基因混合遗传模型进行RIL遗传分析,结果表明,NJRIKY群体的耐盐性遗传符合F-3模型,即由3对主基因控制,没有多基因修饰,主基因遗传率是64．4％。利用CartographerV．2．5进行QTL定位,结果显示,共检测到3个耐盐QTL,它们分别位于B1、G和K三个连锁群上,分别解释8．4％、17．9％和11．3％的表型变异。     

甘蓝型油菜角果皮叶绿素含量的QTL分析

利用甘蓝型黄籽油菜GH06和甘蓝型黑籽油菜P174为亲本,通过单粒法连续自交6代构建重组自交系群体,进而构建的遗传连锁图谱,对2007年和2008年群体中每个株系的角果皮叶绿索含量进行QTL分析。复合区间作图法分析结果共检测到9个QTL,单位点贡献率在5．75％-10．82％之间,其中在第7连锁群有QTL重叠的区域。本研究认为油菜角果叶绿素含量属于典型的数量性状,受环境影响很大,与这些QTL紧密相关的分子标记可以对油菜角果叶绿素及其相关光合性状的研究奠定基础。     

Genetic Architecture of Grain Yield-Related Traits in Sorghum and Maize

Grain size, grain number per panicle, and grain weight are crucial determinants of yield-related traits in cereals. Understanding the genetic basis of grain yield-related traits has been the main research object and nodal in crop science. Sorghum and maize, as very close C4 crops with high photosynthetic rates, stress tolerance and large biomass characteristics, are extensively used to produce food, feed, and biofuels worldwide. In this review, we comprehensively summarize a large number of quantitative trait loci (QTLs) associated with grain yield in sorghum and maize. We placed great emphasis on discussing 22 fine-mapped QTLs and 30 functionally characterized genes, which greatly hinders our deep understanding at the molecular mechanism level. This review provides a general overview of the comprehensive findings on grain yield QTLs and discusses the emerging trend in molecular marker-assisted breeding with these QTLs.     

Identification of QTLs and a Candidate Gene for Reducing Pre-Harvest Sprouting in Aegilops tauschii–Triticum aestivum Chromosome Segment Substitution Lines

Wheat pre-harvest sprouting (PHS) causes serious losses in wheat yield. In this study, precise mapping was carried out in the chromosome segment substitution lines (CSSL) F₂ population generated by a direct cross of Zhoumai 18 (PHS-sensitive) and Aegilops tauschii accession T093 (highly PHS-resistant). Three Ae. tauschii-derived quantitative trait loci (QTLs), QDor.3D.1, QDor.3D.2, and QDor.3D.3, were detected on chromosome 3DL using four simple sequence repeats (SSR) markers and 10 developed Kompetitive allele-specific PCR (KASP) markers. Alongside these QTL results, the RNA-Seq and qRT-PCR analysis revealed expression levels of TraesCS3D01G466100 in the QDor.3D.2 region that were significantly higher in CSSLs 495 than in Zhoumai 18 during the seed imbibition treatment. The cDNA sequencing results of TraesCS3D01G466100 showed two single nucleotide polymorphisms (SNPs), resulting in two changed amino acid substitutions between Zhoumai 18 and line 495, and the 148 nt amino acid substitution of TraesCS3D01G466100, derived from Ae. tauschii T093, which may play an important role in the functioning of ubiquitin ligase enzymes 3 (E3) according to the homology protein analysis, which could lead to differential PHS-resistance phenotypes. Taken together, our results may foster a better understanding of the mechanism of PHS resistance and are potentially valuable for marker-assisted selection in practical wheat breeding efforts.     

甘蓝型油菜（Brassica napus L．）RIL群体抗倒伏及其相关性状的QTL分析

油菜倒伏严重影响了油菜的产量和品质,为了定位甘蓝型油菜（Brassica napus L．）与抗倒伏性状相关的QTL,用抗倒伏品系浙平1号和易倒伏品系高芥1号组合重组自交系（RIL）家系为材料,通过两年两点试验,对该RIL群体的F2：6和F2：7,家系抗压力性状进行了QTL分析,并应用一年两点数据对该群体F2：6。家系结角层性状进行了QTL分析。结果表明,在4个试验中共检测到11个家系抗压力QTL,可解释4．41％～52．64％的表型变异,LOD值范围是2．68～26．58。其中qRP16-1可以在3个不同的试验中（南京-2012、溧水-2012和南京-2013）重复检测到,面P1、qRP4和qRP8-1同时在2个不同的试验中（溧水-2012和溧水-2013）重复检测到。qRP2-1、qRP2-2、qRP8-2、qRP8—3、qRPl6—2、qRP3和qRP8—4等7个QrL只能在特定的试验中检测到。同一地点不同年份间家系抗压力性状QTL相对同一年份不同地点间易被重复检测到。在2个试验中共检测到2个结角层厚度QTL,位于第15连锁群的qTPLl5在2个试验中重复检测到。     

Quantitative Trait Locus Mapping of Salt Tolerance in Wild Rice Oryza longistaminata

Salt stress is one of the most severe adverse environments in rice production; increasing salinization is seriously endangering rice production around the world. In this study, a rice backcross inbred line (BIL) population derived from the cross of 9311 and wild rice Oryza longistaminata was employed to identify the favorable genetic loci of O. longistaminata for salt tolerance. A total of 27 quantitative trait loci (QTLs) related to salt tolerance were identified in 140 rice BILs, and 17 QTLs formed seven QTL clusters on different chromosomes, of which 18 QTLs were derived from O. longistaminata, and a QTL for salt injury score (SIS), water content of seedlings (WCS) under salt treatment, and relative water content of seedlings (RWCS) was repeatedly detected and colocalized at the same site on chromosome 2, and a cytochrome P450 86B1 (MH02t0466900) was suggested as the potential candidate gene responsible for the salt tolerance based on sequence and expression analysis. These findings laid the foundation for further improving rice salt tolerance through molecular breeding in the future.     

Pangenomes as a Resource to Accelerate Breeding of Under-Utilised Crop Species

Pangenomes are a rich resource to examine the genomic variation observed within a species or genera, supporting population genetics studies, with applications for the improvement of crop traits. Major crop species such as maize (Zea mays), rice (Oryza sativa), Brassica (Brassica spp.), and soybean (Glycine max) have had pangenomes constructed and released, and this has led to the discovery of valuable genes associated with disease resistance and yield components. However, pangenome data are not available for many less prominent crop species that are currently under-utilised. Despite many under-utilised species being important food sources in regional populations, the scarcity of genomic data for these species hinders their improvement. Here, we assess several under-utilised crops and review the pangenome approaches that could be used to build resources for their improvement. Many of these under-utilised crops are cultivated in arid or semi-arid environments, suggesting that novel genes related to drought tolerance may be identified and used for introgression into related major crop species. In addition, we discuss how previously collected data could be used to enrich pangenome functional analysis in genome-wide association studies (GWAS) based on studies in major crops. Considering the technological advances in genome sequencing, pangenome references for under-utilised species are becoming more obtainable, offering the opportunity to identify novel genes related to agro-morphological traits in these species.