“外选35”和“七丝占”重组自交系群体抗稻瘟病QTL的初步定位

以中国华南地区曾普遍使用的抗瘟性水稻材料外选35和广东最早的优质食味好的品种七丝占为亲本材料,建立的重组自交系群体。利用广东省水稻育种新技术暨农业部水稻遗传改良重点实验室分离的广东稻区稻瘟菌ZC-13和ZC-15两个小种进行单小种接种鉴定抗瘟性,利用QTLmapper2.0进行抗瘟性QTL定位分析。结果共检测到2个QTL,均位于第12号染色体的RM117-RM179区间。对由外选35育成的7个抗性品种进行检测分析,所选的品种该区段均来源于外选35,初步验证该区段可能含抗稻瘟病位点。     

Mapping QTL involved in adult plant resistance to powdery mildew in the winter wheat line RE714 in two susceptible genetic backgrounds

The objective was to study the genetic basis of adult plant resistance to powdery mildew of the winter wheat line RE714 by quantitative trait loci (QTL) analysis and to investigate the stability of the QTL detected in two different genetic backgrounds. Two DH populations from the crosses between RE714 and the susceptible parents ‘Festin’ and ‘Hardi’ were used. Reaction of the DH lines to powdery mildew was assessed in different environments in Belgium under natural disease infection. Considering both populations and according to the environment tested, one to seven QTL were detected. Among them, residual effects of the race‐specific resistance genes Pm4b and MIRE were found. Two major QTL were very stable (on chromosome 5D and at the MIRE locus), since they were detected in both populations and over all environments tested. The QTL detected varied according to the susceptible parent used, and a residual effect at the Pm4b gene was not observed with the genetic background of ‘Hardi’.     

A genetic linkage map in southern‐by‐spring oat identifies multiple quantitative trait loci for adaptation and rust resistance

We developed 178 recombinant inbred lines from a southern‐by‐spring oat population designated as “TxH.” These lines were genotyped to generate a high‐quality linkage map that resolved 6,902 markers into 21 linkage groups that matched closely with the latest hexaploid oat consensus map. Three major quantitative trait loci (QTLs) affecting heading date were found in locations that are consistent with known QTLs and candidate genes, and two other QTLs affecting heading date were found in novel locations. Five QTLs affecting plant height were found. Both sets of QTLs are responsible for transgressive segregation observed for these two traits. Four QTLs affecting resistance to crown rust, caused by the pathogen Puccinia coronata f. sp. avenae, were identified. Two of these QTLs are consistent with known clusters of rust resistance genes, while two may represent new locations of novel rust resistance genes. A complete set of SNP sequences suitable for generating markers for molecular selection is provided.     

The Identification of QTL Associated with Cotton Fruit Branch Length Suitable for Mechanized Harvest Utilizing BSA-seq

[Objective] This study aims to identify quantitative trait loci (QTLs) associated with cotton fruit branch length by using the combination of bulked-segregant analysis (BSA) and next-generation sequencing (NGS) method. [Method] In this study, the cotton F₂ segregating population was developed with the short branch line Sujimian 125 and long-branch variety Sikang 1 as cross parents. According to the average internode length of fruit branches in middle, extreme individuals in F₂ population were divided into two groups to generate the bulked DNA samples. The whole-genome resequencing of two DNA bulks was applied to analyze the single nucleotide polymorphism (SNP) and insertion-deletion (InDel) between two groups, and the fruit branch internode length related QTLs were detected using Euclidean distance (ED). [Result] With SNP data obtained from sequencing, a 0.8 Mbp range associated region on chromosome A3 was identified; with InDel data obtained from sequencing, a 1.09 Mbp range associated region on chromosome A3 was identified. Two regions overlapped, and the overlapped range was 0.77 Mbp. [Conclusion] This result suggested that the difference between I-type fruit branch and zero-type was due to different genetic locus and pattern rather than dosage effect of the same gene.     

水稻黑条矮缩病抗性QTL定位

发掘水稻黑条矮缩病的抗性基因有助于抗病品种的选育,减少黑条矮缩病对水稻生产的危害。本研究构建了包含222个家系的L5494/IR36重组自交系群体。对该群体进行黑条矮缩病的田间诱发鉴定,抗性亲本IR36发病率为28.70%,感病亲本L5494发病率为84.26%,群体发病率范围为11.21%～89.81%。利用134对分子标记构建覆盖12条染色体的遗传连锁图谱,总遗传距离为1475.97 cM,平均标记间距为11.1 cM。利用QTL IciMapping 4.0对抗黑条矮缩病QTL进行分析,共检测到4个QTL,其中第1、第2、第9染色体上QTL的表型贡献率分别为12.64%、16.00%和8.43%,抗病等位基因来自抗病亲本IR36;第6染色体上QTL的表型贡献率为10.82%,抗病等位基因来自感病亲本L5494。在此基础上,利用93-11为供体、日本晴为背景的近等基因系材料,在qRBSDV-1定位区间内检测到来自93-11的抗性QTL。本研究结果为水稻黑条矮缩病抗性基因定位及分子标记辅助选择育种提供借鉴。     

利用BSA-seq发掘棉花适宜机采的果枝长度相关QTL

【目的】将群体分离分析法与下一代测序技术相结合,定位与棉花果枝长度关联的数量性状位点。【方法】以Ⅰ式果枝品系苏机棉125和Ⅱ式果枝品种泗抗1号为亲本,构建棉花F2分离群体。根据F2群体单株中部果枝节间平均长度,选择极端性状单株分为2组,构建DNA混池。再对2个混池进行重测序,分析2个混池之间的单核苷酸多态性和插入缺失突变,并利用欧式距离法关联与果枝节间长度相关的数量性状位点。【结果】利用测序获得的单核苷酸多态性位点数据,在A3染色体上定位到1个与果枝节间长度关联的区域,区间范围为0.8Mbp;利用测序获得的缺失突变位点数据,也在A3染色体上定位到1个关联区域,区间范围为1.09Mbp;2个关联区域互相重合,重合区间为0.77Mbp。【结论】本研究中Ⅰ式果枝相关基因被定位在A3染色体上,说明棉花Ⅰ式果枝和〇式果枝的差异是因为遗传位点和模式的不同,而不是同一基因的剂量效应。     

陆海高代回交群体抗黄萎病QTL定位

【目的】定位棉花抗黄萎病数量性状位点(Quantitative trait loci, QTL)。【方法】以海7124和TM-1配制抗感组合F1,再以鲁棉研28为轮回亲本构建的137个BC4F1家系为作图群体,筛选出多态性重复序列(Simple sequence repeat, SSR)标记,并与已发表的整合高密度遗传连锁图谱相比对,构建遗传图谱。采用复合区间作图法(Composite interval mapping,CIM)进行大田和病圃两个环境下抗黄萎病QTL定位。【结果】216个多态性SSR位点分布在26条染色体上,可覆盖棉花基因组3 380 cM(centi Morgan),标记间平均距离15.77 cM。定位到6个QTLs,分布在6条染色体上,可解释表型变异8.56%~20.26%,其中5个QTLs与前人研究结果相一致,在第1染色体上新定位到一个QTL。本研究可为分子标记辅助选择抗病育种提供帮助。【结论】定位到6个黄萎病相关QTLs,其中1个是在第1染色体上新发现的QTL。     

棉花分子遗传图谱构建和纤维品质性状QTL分析

以陆地棉(Gossypium hirsutum L.)中棉所8号和海岛棉(Gossypium barbadense L.) Pima90-53组配衍生的214个单株的F₂群体为材料,构建了包含110个SSR标记和65个AFLP标记的遗传连锁图谱。该图谱共包括42个连锁群,连锁群长度为4.5~147.3 cM,包括2~22个分子标记,标记间平均距离为11.6 cM,总长为2 030 cM,约占棉花全基因组的40.6%。应用复合区间作图法分析该组合的F₂单株和F_2:3家系纤维品质性状,共得到25个纤维品质数量性状基因座(QTL),其中5个与纤维长度相关s,分布在Chr.21、Chr.15、LG2和LG12上,可解释表型变异的10.2%~35.8%;4个与整齐度相关,分布在Chr.21、LG9、LG18和LG12上,可解释表型变异的12.6%~36.6%;7个与马克隆值相关,分布在Chr.9、LG1、LG9、LG20和LG12上,可解释表型变异的11.5%~26.1%;7个与断裂比强度相关,分布在Chr.21、Chr12、Chr.8、LG1、LG4和LG10上,可解释表型变异的16.5%~52.8%;2个与伸长率相关,分布在Chr.9和Chr.21上,可解释表型变异的18.1%和27.1%。LG9、LG12和Chr.21上存在QTL聚集区。     

大豆蛋白质有关性状的QTL定位

以科丰1号×南农1138-2组合衍生的184个重组自交家系(简称RIKY)和(Essex×ZDD2315)×ZDD2315衍生的114个BC₁F₂家系(简称BIEX)为材料,对蛋白质含量、蛋油总量与油脂含量,11S、7S、11S/7S,11S-1~11S-4, 7S-1~7S-6等4组16个性状利用WinQTL Cartographer Ver.2.5的复合区间作图法(CIM)、多区间作图法(MIM)和IciMapping Ver.2.0的完备区间作图法(ICIM)进行QTL分析, 结果表明：(1) 在RIKY和BIEX群体分别定位到17⁺个和21⁺个QTL,合计38⁺个QTL;在RIKY有蛋白、油脂、蛋油总量QTL11个,在11S和7S亚基组上分别只有1⁺和3⁺个;在BIEX有前性状QTL2⁺个,有后性状QTL分别9⁺和6⁺个;(2) 两群体16个性状上均没有检测到共享的QTL,说明两群体的蛋白质有关性状具有完全不同的遗传基础;RIKY的两个亲本间蛋白、油脂和蛋油总量有明显遗传差异,但在亚基组上遗传差异不大,而BIEX则反之;(3) 4组总、分性状中,两群体一致表现出蛋白、油脂和蛋油总量和11S、7S和11S/7S比值两组在总、分性状间共享QTL(共同遗传基础), 而11S亚基组和7S亚基组两组性状在总、分性状间无共享的QTL;(4) 蛋白质有关性状QTL定位结果和分离分析结果共同表明这类性状主效基因和微效基因均占较大比重,要考虑两者兼用的育种方法。