大豆定向选择群体耐旱性位点基因型分析及QTL定位

利用Clark导入到红丰11为背景的回交导入系进行萌芽期和苗期的连续性耐旱鉴定,经萌芽期鉴定,获得36个耐旱定向选择导入系。对耐旱选择导入系进行全基因组SSR标记扫描,并以随机群体作为对照,计算供体基因型的导入频率,利用卡方测验检测显著偏分离的SSR标记位点,并结合GGT图示基因型软件对各染色体连锁群进行分析。其中在L连锁群的Satt398和Satt156两个位点有显著的供体片段“超导入”现象,供体基因型导入频率为0.9167和0.9583,卡方值高达182和201.5。另外,在F连锁群的Satt423,K连锁群的Satt167以及N连锁群的Sat_084等位点也出现供体导入片段的偏分离现象。同时,对萌芽期耐旱鉴定中相对发芽率表现超亲的35个株系采用性状－标记间的单向方差分析(P<0.01)和QTL定位, 共检测到14个控制相对发芽率的QTL,分布在4个连锁群上,其中与卡方测验检测的结果相比较,在Satt156,Satt423,Sattt167等位点具有一致性,说明这些位点是与大豆耐旱性紧密相关的QTL位点。以上结果为进一步开展大豆耐旱性有利基因的精细定位、克隆和分子设计育种奠定了基础。     

野生大豆染色体片段代换系百粒重的选择牵连效应及响应分析

利用野生大豆导入系群体和多位点扫描分析方法研究了针对百粒重性状的选择牵连效应,找到与百粒重性状相关联的位点,并分析了这些位点在选择条件的响应。随机群体28.10%的位点出现偏分离(P0.05),经百粒重选择后等位基因偏分离比例减少,偏分离程度加大。标记异常偏分离率缩小到4.13%和23.14%,卡方值变幅缩小至0~166.67和0.01~81.30。对随机群体和选择群体的供体片段导入频率,在P0.05水平下进行卡方分析,定位到与百粒重相关的的12个位点。     

利用选择回交导入群体定位大豆蛋白质含量QTL

大豆是重要的植物蛋白来源,定位大豆蛋白质含量QTL,可为分子标记辅助育种和基因挖掘提供依据。本研究以我国综合性状优良的黄淮海主栽品种中黄13为轮回亲本,日本品种东山69为供体亲本,构建了BC2F2回交导入系群体;利用性状–标记间的单向方差分析和卡方测验检测BC2F2随机群体(RP)及选择回交导入群体(BSP、PSP和NSP)中影响大豆蛋白质含量的QTL。2种方法在4个群体中定位到蛋白质含量相关的QTL 42个,5个位点在随机群体和极端选择群体中被多次重复检测到,分别为Sat_202、Satt170、Satt282、Sat_074、和Satt146;单向方差分析在随机群体和双向选择群体中同时检测到Sat_077、Sat_202、Satt282、Satt146和Satt712等5个效应值较大(10%)的蛋白质含量QTL,分别位于C1、C2、D1b、F和J连锁群上,位于D1b和J连锁群上的Satt282和Satt712效应最大,F值达到8.77、7.80和9.01、11.61,与其连锁的QTL能解释的表型变异分别达13.55%、21.40%和13.85%、28.82%;卡方测验在极端选择群体中检测到的8个QTL与单向方差分析在随机群体中检测到的位点一致,其中双向选择群体检测到4个(Sat_202、Satt301、Sat_074和Satt146)、正向选择群体检测到2个(Satt250和Satt485)、负向选择群体检测到5个(Sat_202、Satt170、Satt282、Sat_074和Satt146)。定位到42个蛋白质相关QTL,结果表明单向方差分析对双向选择群体有一定的应用价值,卡方测验更适合单向选择群体的QTL检测。     

东北地区大豆主栽品种油份蛋白含量的关联分析

为探寻与大豆油份含量、蛋白含量相关的关键位点,本研究选取中国东北地区92份大豆主栽品种及常用种质资源品种群体基于蛋白含量和油份含量的Meta分析,进行基于数学模型的类群划分评价,估测样本群体的结构,应用简单线性模型分析与大豆油份含量、蛋白含量相关的的位点。结果表明,通过多次迭代测试,当K=5时,即该资源群体可以分为5个亚群时,为最稳定的分类结果,并在显著水平下（p<0.05）,贡献率大于1%的标记中,得到与大豆油份含量相关标记有Sat_412,Sat_195,Satt317,Sat_187,Sat_195,Satt255,Satt713,Satt468,Satt267,Satt686,Sat_294和AZ302047,对油分含量的总贡献率为39.54%。蛋白质含量相关标记有Satt683,Sat_311,Satt578,Satt181,Satt317,Satt700,Satt713,Satt255,Sat_242和Satt720对蛋白质含量总贡献率为48.39%。这些重要的标记位点为大豆油份含量和蛋白含量的分子辅助育种提供重要基础。     

基于野生大豆导入系的大豆粒长和粒宽的QTL分析

以野生大豆ZYD00006(父本)和绥农14(母本)为亲本构建的导入系为定位群体,群体含有102个株系,遗传图谱使用了329个SSR标记位点,针对粒长和粒宽2个籽粒性状进行定位分析。结果表明:有18个位点存在不同性状间被同时检测到的情况,其中与QTL连锁的位点Sat_227、Satt338和Satt568被2个性状同时检测到。通过比较分析也发现3个位点也同时影响着百粒重的大小,进一步通过加性效应分析表明,定位区段对粒长的影响为-10%~15.4%,定位区段对粒宽的影响为-26.72%~2.76%。明确导入位点对粒长和粒宽的影响,可以作为进一步大豆粒长和粒宽相关基因挖掘。     

野生大豆芽期耐盐性状的关联分析

盐渍化是危害大豆生产的主要非生物胁迫因素之一。目前大豆耐盐性研究主要集中在栽培大豆的苗期耐盐性,而芽期耐盐性状的研究相对较少。野生大豆蕴含丰富的耐逆基因,是栽培大豆遗传改良的重要资源。为了研究野生大豆芽期耐盐性状的遗传机制,以113份野生大豆为试验材料,进行芽期耐盐性状的鉴定,结合群体的分子标记对包括2年平均值在内的3个环境下的3个耐盐指数进行全基因组关联分析,共检测到与野生大豆芽期耐盐相关的位点26个,6个SSR标记Satt521、Satt022、Satt239、Satt516、Satt251和Satt285在2个或3个环境下均被检测到,4个SSR标记Satt516、Satt251、Satt285和GMES4990与2个或3个耐盐指数显著相关。对这些SSR标记进行分析,挖掘了最优的等位基因及其载体材料。以上这些结果对于阐明野生大豆芽期耐盐性状的遗传机制,进一步发掘新的耐盐基因具有重要意义。同时也为栽培大豆遗传基础的拓宽、大豆耐盐分子标记辅助选择和分子设计育种等后续研究提供重要依据。     

大豆四向重组自交群体单株产量QTL单标记分析

以(垦丰14×垦丰15)×(黑农48×垦丰19)衍生的含160个株系的大豆四向重组自交系群体为试验材料,应用154个SSR标记鉴定个体基因型,利用单标记分析方法,对2013和2014年在哈尔滨和克山两地4个环境下的单株产量进行QTL定位分析。结果显示:共检测到46个与单株产量相关的QTL位点,主要分布在A1、A2、C1、C2、D2、D1b、L、K、B2、N、E、J、F、G和H连锁群上,遗传率为0.15%~9.37%。遗传率较高的标记位点有BARCSOYSSR_02_0607、BARCSOYSSR_03_1620、BARCSOYSSR_19-0451、Sat_153、Sat_367、Satt229和Satt529,优异等位基因型为BARCSOYSSR_02_0607(Q1Q1)、BARCSOYSSR_03_1620(Q2Q2)、BARCSOYSSR_09_0183(Q1Q1)、Satt229(Q2Q2)、Sat_367(Q3Q3)、Satt338(Q1Q1)、Satt229(Q1Q1)和Satt668(Q1Q1)。在检测的标记位点中,BARCSOYSSR_08_0966、Sat_36、Sat_153、BARCSOYSSR_02_0607和Satt529在两个环境中重复检测,表明这5个QTL可用于分子设计育种改良单株产量。     

利用玉米选择导入系进行营养生长期抗旱性基因组区段定位

采用我国优异骨干自交系黄早四与掖478的回交群体(BC₂S₁和BC₃S₁)的抗旱性选择导入系群体,通过SSR标记检测群体中等位基因的导入频率,利用卡方检验对等位基因导入频率进行检测,同时结合表型-基因型方差分析(ANOVA)的方法,对抗旱群体进行抗旱性相关位点的分析。结果表明：利用卡方测验检测到31个供体等位基因导入,利用方差分析检测到98个位点导入,其中有17个位点是重合的,这些导入位点可能是抗旱相关的重要的候选基因组区段。     

应用关联分析挖掘大豆对灰斑病12号生理小种的抗性位点

利用126份SSR标记对320份对大豆灰斑病12号生理小种具有不同抗性的大豆材料进行基因组扫描、群体结构和连锁不平衡分析,并用STRUCTURE软件、TASSEL软件中的GLM分析方法对大豆抗性进行关联分析。结果表明:320份大豆品种中有23个表现高抗,53个表现抗病,178个表现中抗,56个感病,10个高感。找到与大豆抗灰斑病12号生理小种的相关位点共7个:H连锁群上的Satt052、F连锁群上的Satt335、C2连锁群上的Satt557、A1连锁群上的Sat_368、D1a连锁群上的Sat_346、O连锁群上的Satt243、J连锁群上的Sat_151。     

大豆耐旱选择群体基因型分析与株高QTL定位

以红丰11为轮回亲本、Clark为供体亲本构建回交群体进行耐旱性鉴定,并对获得的选择群体进行全基因组SSR标记扫描.计算供体基因型导人频率,同时利用卡方测验检测偏分离SSR位点,对株高进行QTL定位.结果表明:卡方测验检测到11个SSR偏分离位点(超导入)分布于8条连锁群;株高共定位8个QTL位点分布于A<,1>、C<...     

Improvement of rice drought tolerance through backcross breeding: Evaluation of donors and selection in drought nurseries

A large-scale backcross breeding project has been undertaken to improve drought tolerance in rice. Over 160 donor cultivars from 25 countries have been used in this project, representing a significant proportion of the genetic variation in cultivated rice. These cultivars were evaluated in field experiments in the Philippines to assess their responses to drought in terms of plant height, heading date, and grain yield. Drought was imposed near heading stage, in experiments that were established either in lowland (anaerobic) fields or upland (aerobic) soil. Despite the poor adaptation of some cultivars to the tropics, it was possible to identify significant variation in plant response to drought treatments, and contrasting effects on flowering delay and growth. Subsequently, 325 BC₂F₂ bulk populations, developed by backcrossing many of these donors to one of three elite recurrent parents, were screened under drought in lowland or upland nurseries. Stress levels were managed to eliminate almost all seed set in recurrent parents, and those progeny that produced grain were selected as being putatively drought-tolerant. The selection intensity varied across years and in selection environments with more severe stress, higher selection intensity could be imposed. The number of plants selected within a population was not associated with the per se drought response of the donors in the direct evaluation, indicating the wide presence of cryptic genetic variation for drought tolerance in the apparently drought-susceptible cultivars. The genetic background of the recurrent parent affected the number of plants selected, as did the selection environment (upland versus lowland nurseries). These drought-selected introgression lines represent a useful genetic resource to develop improved cultivars for farmers in rainfed or water-scarce rice-growing regions, and also to improve our understanding of the genetic and molecular basis of drought tolerance in rice. Genetic analysis of the selected lines, reported elsewhere, indicated specific regions of high introgression. Yield evaluations of the selected lines are now underway across a range of drought scenarios.     

Characterizing the Saltol Quantitative Trait Locus for Salinity Tolerance in Rice

This study characterized Pokkali-derived quantitative trait loci (QTLs) for seedling stage salinity tolerance in preparation for use in marker-assisted breeding. An analysis of 100 SSR markers on 140 IR29/Pokkali recombinant inbred lines (RILs) confirmed the location of the Saltol QTL on chromosome 1 and identified additional QTLs associated with tolerance. Analysis of a series of backcross lines and near-isogenic lines (NILs) developed to better characterize the effect of the Saltol locus revealed that Saltol mainly acted to control shoot Na⁺/K⁺ homeostasis. Multiple QTLs were required to acquire a high level of tolerance. Unexpectedly, multiple Pokkali alleles at Saltol were detected within the RIL population and between backcross lines, and representative lines were compared with seven Pokkali accessions to better characterize this allelic variation. Thus, while the Saltol locus presents a complex scenario, it provides an opportunity for marker-assisted backcrossing to improve salt tolerance of popular varieties followed by targeting multiple loci through QTL pyramiding for areas with higher salt stress.     

大豆苗期耐盐性的遗传及QTL定位分析

利用重组自交系群体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Cartographer V.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。     

玉米不同回交世代DH系遗传分析研究

[目的]研究不同回交世代DH系遗传分离规律。[方法]以"A619Ht3×辽3162"构建回交群体BC1F1和BC5F1,利用高频诱导系诱导加倍形成BC1F1和BC5F1的DH系,以DH系为材料,通过比较不同回交世代的DH系和父母本的农艺性状,对其做出评价,同时利用SSR分子标记分析DH系的遗传分离特性。[结果]DH系间株高、穗位高、穗长、穗粗、穗行数、行粒数等农艺性状存在较大的遗传变异,回交群体DH系中没有出现明显偏分离比例,通过χ^2检测,未达到显著水平。[结论]不同回交世代所创制的DH系的主要农艺性状差异均达到极显著水平,回交群体DH系中不存在明显的偏分离现象。     

Survival and recovery of tall fescue genotypes: association with root characteristics and drought tolerance

Identification and selection of plant genotypes with survival, recovery and sustainable performance during drought periods is one of the main objectives of plant improvement for arid and semi‐arid regions. This study aimed to evaluate root traits and recovery of tall fescue genotypes after a period of drought stress. A total of twenty four tall fescue genotypes were selected from a wide polycross population and assessed for field drought tolerance based on stress tolerance index (STI) and recovery during 2010–2013. The genotypes were classified as tolerant, moderately tolerant and susceptible based on STI. Then, in 2014, genotypes were assessed in a pot experiment for root characteristics under two levels of moisture environments (control and intense drought stress). In both moisture environments, root length (RL), root area (RA), root volume (RV) and root weight (RW) were negatively correlated with days to recovery (DR). Genotypes that recovered from drought had greater RL, RA, RV and RW than the genotypes unable to recover. Principle component analysis (PCA) was performed to identify genotypes with superior root characteristics, stress tolerance and recovery potential that can be used for future breeding programmes. Results indicated that selection based on combining STI, recovery and extensive root system might improve drought tolerance of tall fescue.     

Marker-assisted genetic analysis of non-acclimated freezing tolerance and cold acclimation capacity in a backcrossSolarium population

Random amplified polymorphic DNA (RAPD) and simple sequence repeat (SSR) markers were used to construct a partial genetic linkage map in a potato backcross population. The population, derived from two diploid wildSolatium species (frost tolerant, able to cold acclimateS. commersonii; frost sensitive, unable to cold acclimateS. cardiophyllum), was used to map quantitative trait loci (QTL) of non-acclimated relative freezing tolerance (NARFT) and cold acclimation capacity (CAC). Precise assessment of these traits allowed distinction of small but significant differences among 35 backcross genotypes. NARFT and CAC were not correlated in the segregating population, suggesting independent genetic control for these two major components of freezing tolerance. The linkage map spanned 479.4 cM and included 77 RAPD markers and two SSR markers, with 38 RAPD and 10 SSR unassigned markers. Two QTLs for NARFT were detected in two different linkage groups, accounting for 44.0% of the phenotypic variation for this trait. Two QTLs for CAC were detected, accounting for 24.9% of the phenotypic variation for this trait. QTLs for NARFT and CAC were detected at separate genomic regions, in support of the independent genetic control of these two traits. QTLs for NARFT and CAC were detected in a linkage group identified as part of chromosome V, suggesting that such chromosome constitutes a prime candidate for fine-mapping. Due to the relatively small progeny size evaluated in this study, additional QTLs for NARFT and CAC could have been involved but not identified. Therefore, the conclusions derived from this study should be considered preliminary.     

水稻SSR及Indel分子标记在籼粳交F_2群体的偏分离分析

偏分离是指遗传标记的观察频率偏离预期的孟德尔式分离频率的现象,其可以增加群体中杂合等位基因或者异型染色体的频率,是一种重要的进化动力。本研究以粳稻材料日本晴及籼稻材料千粒稻为亲本获得80株F2群体,构建了一张含92对SSR标记和44对Indel标记的遗传图谱。结果发现,F2群体中,116个标记表现为偏分离现象(85.29%),其中79个极度偏分离(68.10%)。偏分离标记中由合子偏分离引起的有20个,配子偏分离引起的93个,RM3484,RM3702,os7-38.4既不是由合子选择引起也不是由配子选择引起。Indel标记偏分离率(97.72%)明显高于SSR标记偏分离率(79.34%),且所有偏分离标记皆偏向于千粒稻。结合本研究结果,对偏分离现象产生的原因进行了分析。     

Genetic analysis of rainfed lowland rice drought tolerance under naturally-occurring stress in eastern India: Heritability and QTL effects

Drought tolerance is an important rainfed rice breeding objective, but because the heritability (H) of yield under drought stress is thought to be low, secondary physiological traits are considered better targets for selection than yield under stress per se. This assumption has rarely been tested, and there are no reports on H for yield under drought stress from experiments repeated over seasons in rainfed lowland rice. To assess the potential for improving yield under drought stress via direct selection, and to identify associated quantitative trait loci (QTL), doubled haploid lines with a narrow range of flowering dates, derived from the population CT9993-5-10-1-M/IR62266-42-6-2, were screened under full irrigation and severe drought stress induced by draining the paddy before flowering in 2000–2002 at Raipur, India. Drought stress reduced mean yield by 80%. H was similar in stress and non-stress trials, as was the relative magnitude of the genotype and genotype × year variances. The genetic correlation between yield in stress and non-stress conditions was 0.8, indicating that about 64% of the genetic variation for yield under stress was accounted for by differences in yield potential also expressed in irrigated environments. These results indicate that direct selection for yield under drought stress can produce yield gains under stress without reducing yield potential. There was no secondary trait for which selection resulted in greater predicted response in yield under stress than direct selection for stress yield per se. A QTL was detected on chromosome 1 near sd1 that explained 32% of the genetic variation for yield under stress, but only 4% under non-stress. Its effect was consistent across years. This QTL accounted for much of the variation in drought yield not accounted for by variation in yield potential.     

Association between aflatoxin contamination and drought tolerance traits in peanut

The current study investigates the association between drought tolerance traits and aflatoxin contamination in peanut grown under long-term drought. Two field experiments were conducted at Khon Kaen University, Thailand using a split–split plot design with three drought stress levels as main plots, 11 genotypes as sub-plots, and two soil inoculations of Aspergillus flavus treatments as sub-sub-plots. The effects of temperature, soil moisture and A. flavus population on kernel colonization and aflatoxin contamination, and drought tolerance traits viz. specific leaf area (SLA) and root length density (RLD) were measured. The results demonstrated that elevated soil temperatures and reduced soil moisture, favored aflatoxin production. Drought in combination with higher levels of A. flavus inoculum load in the soil resulted in an increase in the fungal populations in the soil which in turn resulted in increased kernel colonization and subsequent aflatoxin contamination. A combination of SLA and RLD, and kernel colonization had a significant influence on aflatoxin contamination under drought conditions in both seasons (r = 0.73** and 0.76**). The results revealed that drought tolerance traits (SLA and RLD) could be contributing to resistance to aflatoxin contamination suggesting that a combination of SLA, RLD and kernel colonization could be used as selection criteria in selecting parents for aflatoxin resistance.     

基于60K芯片的玉米回交群体精准背景选择策略

利用Maize 6H-60K芯片对京724/京92/京92的BC1代群体进行分子标记辅助背景选择，结合SNP数据特征和回交群体分离特征，开发出一套精准背景选择策略(ABSS:Accurate Background Selection Strategy)及相关算法。从统计结果中选取背景回复程度最高的一批单株作为下一代回交群体的亲本材料。基于Maize 6H-60K芯片分析和筛选产生的28 910个多态性位点，可以对727个样品的背景回复程度进行精细排序，样品背景回复率大部分分布在0.30～0.75(约占样品总数的94.1%)，背景回复率在0.75及以上的样品比例为1.8%。通过分析回交群体重组交换规律以及背景回复率与株高的相关性，进一步验证Maize 6H-60K芯片数据和ABSS的准确性。利用Maize 6H-60K芯片结合ABSS可以精细选择背景回复程度高、重组交换频率相对较低的单株，显著提高背景选择效率，为设计玉米回交群体规模提供参考价值。