花生主要品质性状的QTLs定位分析

以郑8903×豫花4号的215个重组自交系群体（RILs）为材料,采用2008年原阳种植材料(F8)的品质检测数据,运用WinQTLCart 2.5软件进行与花生蛋白质、脂肪及脂肪酸含量相关的QTLs定位分析。研究结果显示,检测到2个与蛋白质含量相关的QTLs,遗传贡献率分别为4.82%和9.66%;2个与脂肪含量相关的QTLs,遗传贡献率分别为5.25%和8.24%。与油酸、亚油酸、硬脂酸和山嵛酸含量相关的QTL各检测到1个,遗传贡献率分别为5.13%、8.28%、24.14%和7.88%;2个与花生酸含量相关的QTLs,遗传贡献率分别为7.12%和18.32%。     

Genetic analysis and QTL mapping of stalk cell wall components and digestibility in maize recombinant inbred lines from B73 × By804

The cell wall composition and structure of the maize stalk directly affects its digestibility and in turn its feed value.Previous studies of stem quality have focused mostly on common maize germplasm,and few studies have focused on high-oil cultivars with high grain and straw quality.Investigation of the genetic basis of cell wall composition and digestibility of maize stalk using high-oil maize is desirable for improving maize forage quality.In the present study,a high-oil inbred line(By804)was crossed as male parent with the maize inbred line B73 to construct a population of 188 recombinant inbred lines(RILs).The phenotypes of six cell-wall-related traits were recorded,and QTL analysis was performed with a genetic map constructed with SNP markers.All traits were significantly correlated with one another and showed high broad-sense heritability.Of 20 QTLs mapped,the QTL associated with each trait explained 10.0%–41.1%of phenotypic variation.Approximately half of the QTL each explained over 10%of the phenotypic variation.These results provide a theoretical basis for improving maize forage quality by marker-assisted selection.     

大豆高蛋白基因分子标记及其在大豆育种中的应用

选用高蛋白大豆黑农35和高油大豆黑农45作为亲本杂交获得F2分离群体,进行大豆高蛋白基因SSR分子标记。共筛选覆盖大豆全基因组的251对SSR引物,其中40对SSR引物在亲本间具有多态性,用这40对SSR引物分别对F2分离群体进行扩增,用Mapmaker Exp3．0和Mapmaker QTL1．1软件进行作图和定位分析。定位得到高蛋白QTL 1个,与satt532连锁,遗传距离为0．2cM,贡献率为32．7％,位于大豆公共遗传图谱的D1a＋Q连锁群。利用该引物在不同大豆材料中进行高蛋白材料检测和筛选,在56份高蛋白材料中筛选到47份,检出率达到83．93％。说明引物satt532具有一定的检测通用性,可以利用它筛选高蛋白大豆材料。     

QTL analysis of cold tolerance at seedling stage in rice (Oryza sativa L.) using recombination inbred lines

Cold tolerance at seedling stage of rice (Oryza sativa L.) is a favorable trait for the stable establishment in temperate and high-elevation areas. In the present study, 71 recombinant inbred lines (RIL) derived from the cross of Asominori (Japonica) and IR24 (Indica) were used to identify quantitative trait loci (QTL) affecting cold tolerance at seedling stage. The putative QTL was further confirmed using some chromosome segment substitution lines (CSSLs), in which IR24 was used as the donor parent and Asominori as the recurrent parent. The average seedling mortality was used as cold tolerance after cold treatment with 6 °C for 7 days and recovery culture with 25 °C for 4 days at three-leaf seedling stage. Three QTL affecting cold tolerance at seedling stage were detected on chromosomes 1, 5 and 6 with LOD scores ranging from 2.2 to 4.1 using composite interval mapping (CIM). Among them, qSCT-1 located in the region of XNpb87-2-C955 on chromosome 1 was a major QTL which explained 24.51% of total phenotypic variance and favorable allele came from japonica parent, Asominori. In addition, IR24 alleles at the other two loci (qSCT-5 and qSCT-6) increased cold tolerance. And these three QTL were confirmed by four lines from the IR24 CSSLs. Transferring favorable allele from japonica variety to indica background or pyramiding different QTL identified from indica is an effective way to improve cold tolerance of rice.     

玉米株型相关性状的QTL定位与候选基因分析

以玉米自交系ZNC442和SCML0849为亲本构建的131份F2:3家系为材料,结合简化基因组测序(GBS)的基因型鉴定结果与该群体在多环境下的株型评价数据,利用完备区间作图法对株高、穗位高、叶夹角、穗上叶片数、雄穗分枝数、雄穗主轴长等株型相关性状进行QTL定位。结果表明,2个环境下共检测到98个株型相关QTL,分布于10条染色体上。结合已公开的QTL定位信息,利用生物信息学分析筛选出5个控制株型相关性状的候选基因。Zm00001eb037290、Zm00001eb033500、Zm00001eb033600、Zm00001eb033610与株高相关,其编码的PosF21转录因子、E3泛素蛋白连接酶ATL6、丝氨酸/精氨酸丰富剪接因子和MYB102转录因子,分别通过参与赤霉素的合成、调节C/N反应、调控细胞分裂素变化等过程调控节间生长发育与植株大小。     

接种根瘤菌环境下大豆叶形遗传及QTL定位分析

为探究接种根瘤菌环境下影响大豆叶形的遗传基础,本研究利用两个叶形具有显著差异的大豆品种及RIL群体,在接种和不接种根瘤菌环境下对大豆叶形性状进行遗传和QTL定位等分析。结果显示,叶形相关性状的遗传率在0.60~0.95之间,环境与基因型间存在互作效应,并且接种根瘤菌可以显著影响叶形指数（LS）与单株粒数（GN）、单株荚数（PD）和单株粒重（GW）的相关系数。此外,两种处理下共检测到8个QTL位点,LOD值范围在2.50~7.03,可解释6.4%~16.9%的遗传变异。其中,qLS-15可解释由根瘤菌×基因型互作引起叶形性状6.4%~9.3%的遗传变异,LOD值在2.50~3.69之间,表明qLS-15是与环境互作的主要遗传位点之一。综上所述,根瘤菌可以通过qLS-15影响大豆叶形,研究结果为解析根瘤菌提升大豆产量的内在机制提供了理论依据。     

基于ILs玉米抗旱相关位点分析

选用抗旱性优良的玉米自交系郑独青为供体,采用高代回交方法构建以自交系昌7-2为主要遗传背景的导入系群体,通过SSR标记检测群体中供体等位基因的导入频率,利用卡方检验对等位基因导入频率的偏离进行检测,同时结合表型-基因型方差分析的方法,对抗旱群体进行抗旱性相关位点分析。结果表明,卡方检验发现显著位点33个,方差分析检测到24个,其中15个位点被两种方法同时检测到。     

大豆对SMV SC-3株系的抗性遗传和QTL分析

为研究大豆对SMV抗扩展的遗传机制,以中豆29×中豆32构建的重组自交系群体(RIL)为材料,人工接种SC-3株系.以病情指数为抗性指标,应用主基因+多基因混合遗传模型进行遗传分析,利用复合区间作图法进行QTL定位.结果表明:该RIL群体对SC-3株系的抗性遗传符合B-2-3遗传模型,即抗性由2对等加性主基因控制,加性效应为-9.78,主基因遗传率为97.65％.在3个染色体上检测到3个抗性相关QTL,表型贡献率为10.80％～13.41％.     

Identification of QTLs associated with cadmium concentration in rice grains

Cadmium(Cd) contamination in rice has been a hot topic of research because of its potential risk to human health. In this study, a double haploid(DH) population derived from Zhongjiazao 17(YK17)(an early-season indica cultivar)×D50(a tropical japonica cultivar) was used to identify quantitative trait loci(QTLs) associated with Cd concentration in brown rice(CCBR) and Cd concentration in milled rice(CCMR). Continuous and wide variation for CCBR and CCMR were observed among the DH population. Correlation analysis revealed a positive and highly significant correlation between the two traits. A total of 18 QTLs for CCBR and 14 QTLs for CCMR were identified in five different pot and field trials. Two pairs of QTLs for CCBR(qCCBR2-1 and qCCBR2-2, qCCBR9-1 and qCCBR9-2) and one pair of QTLs for CCMR(qCCMR5-1 and qCCMR5-2) were detected in multiple trials. The alleles increasing CCBR at the qC CBR2-1/qC CBR2-2 and qC CBR9-1/qC CBR9-2 QTLs were contributed by YK17 and D50, respectively, whereas the D50 allele at the qCCMR5-1/qCCMR5-2 QTLs increased CCMR. Eight pairs of QTLs for CCBR and CCMR, qCCBR2-2 and qCCMR2-2, qCCBR3 and qCCMR3, qCCBR4-2 and qCCMR4-1, qCCBR4-3 and qCCMR4-2, qCCBR4-4 and qCCMR4-3, qCCBR5 and qCCMR5-2, qCCBR7 and qCCMR7, and qCCBR11-1 and qCCMR11-2, co-localized on chromosomes 2, 3, 4, 5, 7, and 11, respectively. For all of these QTL pairs, except qCCBR5/qCCMR5-2, the additive effects came from YK17. In addition, four CCMR QTLs showing significant additive×environment interaction and two pairs of CCMR QTLs with bi-allelic epistatic interactions were identified. The results of this study could facilitate marker-assisted selection of breeding rice varieties with low Cd accumulation in grain.     

Identification of main effect and epistatic QTLs controlling initial flowering date in cultivated peanut(Arachis hypogaea L.)

Initial flowering date(IFD) is closely related to mature period of peanut pods. In present study, a population of recombinant inbred lines(RIL) derived from the cross between Silihong(female parent) and Jinonghei 3(male parent) was used to map QTLs associated with IFD. The RIL population and its two parental cultivars were planted in two locations of Hebei Province, China from 2015 to 2018(eight environments). Based on a high-density genetic linkage map(including 2 996 SNP and 330 SSR markers) previously constructed in our laboratory, QTLs were analyzed using phenotypic data and the best linear unbiased prediction(BLUP) value of initial flowering date by inclusive composite interval mapping(ICIM) method. Interaction effects between every two QTLs and between individual QTL and environment were also analyzed. In cultivated peanut, IFD was affected by genotypic factor and environments simultaneously, and its broad sense heritability(h2) was estimated as 86.8%. Using the IFD phenotypic data from the eight environments, a total of 19 QTLs for IFD were detected, and the phenotypic variation explained(PVE) by each QTL ranged from 1.15 to 21.82%. Especially, five of them were also detected by the BLUP value of IFD. In addition, 12 additive QTLs and 35 pairs of epistatic QTLs(62 loci involved) were identified by the joint analysis of IFD across eight environments. Three QTLs(qIFDB04.1, qIFDB07.1 and qIFDB08.1) located on chromosome B04, B07 and B08 were identified as main-effect QTL for IFD, which had the most potential to be used in peanut breeding. This study would be helpful for the early-maturity and adaptability breeding in cultivated peanut.