共查询到17条相似文献，搜索用时 253 毫秒
1.
四向杂交设计QTL分析的极大似然方法 总被引：2，自引：0，他引：2
四向杂交（four-way cross）设计是指4个纯系亲本参与杂交衍生分离群体的一种交配设计。尽管国际上已经提出基于四向杂交设计的迭代重新加权最小平方（iteratively reweighed least squares，IRWLS）QTL作图方法，但该方法忽略了双侧标记基因型内QTL基因型的混合分布特性，当QTL位置和标记的位置不重合时作图精度较低。本文根据四向杂交设计的数量遗传模型，发展出基于四向杂交设计和混合分布理论的QTL作图的极大似然估计方法。首先利用染色体上所有标记基因型联合计算该染色体上任一假定位置QTL的条件概率，然后根据混合分布理论建立基于EM算法实现的QTL作图的极大似然估计方法。以计算机模拟数据研究了QTL遗传力、样本容量和分子标记信息含量3个因素对方法的影响，结果表明,（1）在QTL的被发现能力上，标记信息不完全的四向杂交设计仅略低于信息完全时的四向杂交设计；（2）随着QTL遗传力、样本容量和标记信息含量的增大，QTL位置以及效应估计值的准确度和精确度逐步提高。 相似文献
2.
基于NC III和TTC设计的胚乳性状QTL区间作图方法 总被引：1，自引：1，他引：0
根据三倍体胚乳性状的遗传模型, 提出基于NC III以及TTC两种遗传设计的胚乳性状QTL作图新方法, 并通过计算机模拟数据, 对该方法的可行性和有效性进行了分析验证。模拟研究供试因素包括QTL遗传力、F2群体植株数和每家系混合样品测定的胚乳数。考察指标包括QTL的统计功效以及QTL位置和效应估计的准确度与精确度。结果表明, 2种设计均有较高的QTL统计功效, 在供试的大多数处理中, 即使QTL的遗传力只有5%, 其被发现能力也可达100%。两种设计均可有效区分胚乳QTL的各种遗传效应。基于TTC设计的胚乳QTL作图方法, 在QTL的统计功效、位置估计和效应估计上, 均优于NC III设计, 虽然这一优势随着QTL遗传力的提高以及样本容量的增大而有降低的趋势。 相似文献
3.
检测作物数量性状基因与遗传标记连锁关系的方差分析法及其应用 总被引：8，自引：3，他引：8
本文提出利用自交作物单染色体纯合重组系检测数量性状基因座位（QTL）与遗传标记连锁关系的方差分析模型。增加重复可有效地减少样本容量、降底试验误差和提高检测QTL的灵敏度。应用方差分析将控制小麦每穗小穗数的两个QTL-Sn I和Sn II定位在7D染色体的着丝粒区域和长臂上。 相似文献
4.
《分子植物育种》2021,19(14):4690-4695
具有强耐低温发芽直播稻的种子可以克服低温胁迫导致的发育迟缓,保证幼苗旺盛生长。水稻种子耐低温发芽是多基因控制的复杂数量性状,遗传力低,导致育种家对该性状直接选择的效率很低。耐低温发芽QTL定位研究,有助于开展分子标记辅助选择,提高选择效率。本研究发现,江苏省优质粳稻品种‘南粳46’与云南地方品种‘扎西玛’低温发芽率存在极显著差异。利用‘扎西玛’/‘南粳46’RIL群体定位了3个控制低温发芽的QTL (q LTG-2, qLTG-4和qLTG-7),分别位于第2、4和7染色体上。3个QTL分别可以解释7.69%、8.75%和22.93%表型变异。其中,qLTG-2所在的染色体区域未见报道QTL,是新的QTL位点。该结果为耐低温发芽分子标记辅助选择育种提供了材料基础和分子标记。 相似文献
5.
用闭合三角形杂交群体检测QTL等位位点差异 总被引：1，自引：0，他引：1
本文简述QTL定位和数量性状分子标记辅助选择的基本原理、基本方法,以及在实际应用中存在的一些问题。将12个不同作图群体构建的刚UP或SSR分子标记连锁图,根据其大多数分子标记所在的染色体节,再按每条染色体在各自连锁图中的相对长度整合在一起,然后将所定位的玉米株高QTL转换成整合图上的相对位置。结果发现,12个作图群体定位的75个玉米株高QTL位点遍布整个染色体组,QTL定位的重演性不高。分析认为,这是数量性状受众多微效多基因控制的必然现象。最后,提出用闭合三角形杂交群体进行QTL定位,检测QTL等位点的多重差异,并设想用这种方法验证或提高不同作图群体定位同一数量性状QTL的重演性。 相似文献
6.
7.
基于玉米BC2F2群体的穗部性状QTL分析 总被引：5，自引：0，他引：5
以农系110为受体、农系531为供体材料,采用回交法构建了样本容量为95株的BC2F2回交群体,选取126个均匀分布在10条染色体上的多态性SSR标记进行6个穗部性状QTL分析.结果表明,受体农系110的穗长、穗粗、穗行数、行粒数、百粒重和穗粒重6个穗部性状表型值分别增加了9.4%,9.6%,4.1%,2.7%,0.35%和4.4%;构建一张含126个SSR标记的玉米分子标记连锁遗传图谱,总长度为2 317.4 cM,平均区间长18.4 cM;采用复合区间作图法,定位了19个与玉米穗部性状有关的QTL,其中穗长QTL 4个,穗粗QTL 2个,行粒数QTL 1个,穗行数QTL 3个,百粒重QTL 4个,穗粒重QTL 5个. 相似文献
8.
标记辅助选择育种中QTL基因型的多点联合推断 总被引：1，自引：0，他引：1
传统的育种方法对数量性状的选择存在很大难度,现代分子标记技术为实现控制数量性状基因的准确选择提供了有效的技术手段。目前分子标记辅助选择实践仅是对标记基因型的选择,而非直接对QTL基因型进行选择。尽管标记基因型容易获得,但标记基因型通常并非QTL基因型,除非有关的QTL恰巧在标记座位。因此,如何鉴别QTL的基因型成为分子标记辅助选择的关键。QTL基因型通常需要通过分子标记基因型进行推断,由于标记信息的不完全或缺失,使得对个体QTL基因型的鉴别会发生困难。本文在四向杂交设计的基础上,结合贝叶斯理论和马尔可夫链原理,提出一种通用的QTL基因型多点联合推断方法,该方法能够很方便地处理显性标记和缺失标记,同时结合标记信息和表型数据联合推断QTL基因型的条件概率。模拟研究发现,表型数据选择的效果较差,其选择的个体QTL基因型基本上都是错误的,而应用本文所论述的方法,将表型数据与标记数据相结合选择,对QTL基因型的判断正确,且推断的把握性很高。 相似文献
9.
黄瓜种子长度的遗传分析及分子标记 总被引：1，自引：0，他引：1
为了今后正确制定籽用黄瓜育种方案和有效地进行品种选育,有必要对黄瓜种子大小进行详细研究。选用种子长短不同的5个黄瓜自交系作为杂交亲本,按照Griffing双列杂交试验方法Ⅱ配制杂交组合。以长种子自交系D06157和短种子自交系D0603为亲本,构建F2分离群体,采用SSR分子标记构建遗传连锁图谱,利用复合区间定位方法进行QTL定位。结果表明：黄瓜种子长度属于数量性状,以显性效应为主,同时存在加性效应,广义遗传力及狭义遗传力较低,分别为28.6777%、10.8384%。构建的4个连锁群含有16个SSR位点,连锁群总长度为287.1 cM,标记间平均距离为17.94 cM。检测出6个与黄瓜种子长度相关的QTL,其中QTL5和QTL6有着较高的对种子长度性状变异的解释率(>5%),距离最近标记的图距分别为2.1 cM、4.3 cM,LOD值分别为7.84、9.69,可解释遗传变异分别为6.07%、6.08%,加性效应值分别为39.12%、37.21%。 相似文献
10.
葡萄是世界性广泛种植的果树之一,由于其世代周期长、遗传背景复杂等特点,传统的杂交育种进展缓慢。近年来,随着基因组测序技术发展,越来越多葡萄的数量性状基因座(quantitative trait locus,QTL)位点被解析,并应用到分子标记辅助育种中,极大提高了葡萄育种效率并加速了育种进程。本研究阐述了葡萄QTL定位研究的理论基础,总结了几十年来DNA分子标记和QTL作图方法的发展历程,重点介绍了目前已被解析的葡萄数量性状遗传位点,以期为更多数量性状位点的挖掘和应用提供借鉴,并为葡萄数量性状遗传调控机制的研究提供参考。 相似文献
11.
José Marcelo Soriano Viana Fabyano Fonseca e Silva Gabriel Borges Mundim Camila Ferreira Azevedo Hikmat Ullah Jan 《Euphytica》2017,213(1):13
The efficiency of quantitative trait locus (QTL) mapping methods needs to be investigated assuming high single nucleotide polymorphism (SNP) density and low heritability QTLs. This study assessed the efficiency of the least squares, maximum likelihood, and Bayesian approaches for QTL mapping assuming high SNP density and low heritability QTLs. We simulated 50 samples of 400 F2 individuals, which were genotyped for 1000 SNPs (average density of one SNP/centiMorgan) and phenotyped for three traits controlled by 12 QTLs and 88 minor genes. The genes were randomly distributed in the regions covered by the SNPs along ten chromosomes. The QTL heritabilities ranged from approximately 1–2% and the sample sizes were 200 and 400. The power of QTL detection ranged from 30 to 60%, the false discovery rate (FDR) ranged from only 0.5–1.2%, and the bias in the QTL position ranged from 4 to 6 cM. The QTL mapping efficiency was not influenced by the degree of dominance. The statistical approaches were comparable regarding the FDR. Regression-based and simple interval mapping methods showed equivalent power of QTL detection and mapping precision. Compared to interval mapping, the inclusive composite interval mapping provided slightly greater QTL detection power and mapping precision only for the intermediate and high heritability QTLs. By maximizing the prior number of QTLs, the Bayesian analysis provided the greatest power of QTL detection. No method proved to be superior. 相似文献
12.
S. Rakshit P. Winter M. Tekeoglu J. Juarez Muñoz T. Pfaff A.-M. Benko-Iseppon F.J. Muehlbauer G. Kahl 《Euphytica》2003,132(1):23-30
Resistance of chickpea against the disease caused by the ascomycete Ascochyta rabiei is encoded by two or three quantitative trait loci, QTL1, QTL2 and QTL3. A total of 94 recombinant inbred lines developed
from a wide cross between a resistant chickpea line and a susceptible accession of Cicer reticulatum, a close relative of cultivated chickpea, was used to identify markers closely linked to QTL1 by DNA amplification fingerprinting
in combination with bulked segregant analysis. Of 312 random 10mer oligonucleotides, 3 produced five polymorphic bands between
the parents and bulks. Two of them were transferred to the population on which the recent genetic map of chickpea is based,
and mapped to linkage group 4. These markers, OPS06-1 and OPS03-1, were linked at LOD-scores above 5 to markers UBC733B and
UBC181A flanking the major ascochyta resistance locus. OPS06-1 mapped at the peak of the QTL between markers UBC733B (distance
4.1 cM) and UBC181A (distance 9.6 cM), while OPS03-1 mapped 25.1 cM away from marker UBC733B on the other flank of the resistance
locus. STMS markers localised on this linkage group were transferred to the population segregating for ascochyta resistance.
Three of these markers were closely linked to QTL1. Twelve of 14 STMS markers could be used in both populations. The order
of STMS markers was essentially similar in both populations, with differences in map distances between them. The availability
of flanking STMS markers for the major resistance locus QTL1 will help to elucidate the complex resistance against different
Ascochyta pathotypes in future.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
13.
干旱和灌溉两种处理条件下玉米株高、产量的QTL分析 总被引：1，自引：0，他引：1
为了对玉米的抗旱遗传学研究以及开展抗旱分子标记辅助育种提供有力支撑,利用SSR分子标记技术,构建了玉米基于RIL6群体的遗传连锁图谱,包含101个位点,覆盖玉米基因组1 395.2 cM,标记间平均距离为13.81 cM。在灌溉与干旱两种环境下,对该RIL家系的株高、产量进行QTL初级定位,在灌溉条件下,检测到3个控制株高和3个控制产量的QTL,在干旱条件下,检测到5个控制株高和3个控制产量的QTL,两种水分条件下检测出的QTL不同,并找到1个相对稳定的QTL。 相似文献
14.
大豆重组自交系群体NJRIKY遗传图谱的加密及其应用效果 总被引：1，自引：0，他引：1
作物基因组研究,包括基因或数量性状位点(QTL)定位、图位克隆以及物理图谱构建等,首先必须建立具有丰富标记信息的高密度遗传连锁图谱。由科丰1号和南农1138-2杂交组合衍生的重组自交系群体NJRIKY已经构建了4张大豆遗传连锁图谱,但由于遗传信息和标记数目不够充分,在基因和QTL作图时仍然存在精确度和准确度问题。为增加NJRIKY图谱密度,本研究在967对SSR引物中获得了401个多态性SSR标记。结合其他分子数据,使用作图软件Mapmaker/Exp3.0b,获得一张含有553个遗传标记,25个连锁群,总长2071.6cM,平均图距3.70cM的新遗传连锁图谱,其中SSR标记316个,RFLP标记197个,EST标记39个,形态标记1个。连锁群上大于20cM的标记间隔由原来42个减少到2个。原图谱的3个SMV抗性基因定位于D1b连锁群末端的开放区间上且仅与一个RFLP标记连锁,利用加密图谱对Rsc-3、Rsc-7、Rsc-9、Rsc-13、Rsa、Rn1和Rn3等7个SMV抗性基因重定位,全部位于D1b连锁群,与相邻分子标记距离均小于6cM,其中Rsc-9、Rn1、Rsa的距离小于1cM,Rsc-13与EST标记GMKF168a共分离。对本群体农艺性状进行QTL重定位,获得8个性状相关的42个主效QTL,其中20个QTL遗传贡献率大于10%,与原图谱比较,新定位的各QTL的标记区间明显缩短,与相邻标记的连锁更加紧密。 相似文献
15.
Molecular markers linked to genes for specific rust resistance and indeterminate growth habit in common bean 总被引：2，自引：0，他引：2
Bulked segregant analysis was utilized to identify random amplified polymorphic DNA (RAPD) markers linked to genes for specific resistance to a rust pathotype and indeterminate growth habit in an F2 population from the common bean cross PC-50 (resistant to rust and determinate growth habit) × Chichara 83-109 (susceptible to rust and indeterminate growth habit). Six RAPD markers were mapped in a coupling phase linkage with the gene ( Ur-9) for specific rust resistance. The linkage group spanned a distance of 41 cM. A RAPD marker OA4.1050 was the most closely linked to the Ur-9 gene at a distance of 8.6 cM. Twenty-eight RAPD markers were mapped in a coupling phase linkage with the gene ( Fin) for indeterminate growth habit. The linkage group spanned a distance of 77 cM. RAPD markers OQ3.450 and OA17.600 were linked to the Fin allele as flanking markers at a distance of 1.2 cM and 3.8 cM, respectively. The RAPD markers linked to the gene for specific rust resistance of Andean origin detected here, along with other independent rust resistance genes from other germplasm, could be utilized to pyramid the different genes into a bean cultivar for durable rust resistance. 相似文献
16.
Botrytis grey mould (BGM) caused by Botrytis cinerea Pers. ex. Fr. is the second most important foliar disease of chickpea (Cicer arietinum L.) after ascochyta blight. An intraspecific linkage map of chickpea consisting of 144 markers assigned on 11 linkage groups
was constructed from recombinant inbred lines (RILs) of a cross that involved a moderately resistant kabuli cultivar ICCV
2 and a highly susceptible desi cultivar JG 62. The length of the map obtained was 442.8 cM with an average interval length
of 3.3 cM. Three quantitative trait loci (QTL) which together accounted for 43.6% of the variation for BGM resistance were
identified and mapped on two linkage groups. QTL1 explained about 12.8% of the phenotypic variation for BGM resistance and
was mapped on LG 6A. It was found tightly linked to markers SA14 and TS71rts36r at a LOD score of 3.7. QTL2 and QTL3 accounted
for 9.5 and 48% of the phenotypic variation for BGM resistance, respectively, and were mapped on LG 3. QTL 2 was identified
at LOD 2.7 and flanked by markers TA25 and TA144, positioned at 1 cM away from marker TA25. QTL3 was a strong QTL detected
at LOD 17.7 and was flanked by TA159 at 12 cM distance on one side and TA118 at 4 cM distance on the other side. This is the
first report on mapping of QTL for BGM resistance in chickpea. After proper validation, these QTL will be useful in marker-assisted
pyramiding of BGM resistance in chickpea. 相似文献
17.
Mapping and validation of QTLs for resistance to an Indian isolate of Ascochyta blight pathogen in chickpea 总被引：1，自引：0，他引：1
Pratibha Kottapalli Pooran M. Gaur Sanjay K. Katiyar Jonathan H. Crouch Hutokshi K. Buhariwalla Suresh Pande Kishore K. Gali 《Euphytica》2009,165(1):79-88
Ascochyta blight (AB) caused by Ascochyta rabiei, is globally the most important foliar disease that limits the productivity of chickpea (Cicer arietinum L.). An intraspecific linkage map of cultivated chickpea was constructed using an F2 population derived from a cross between an AB susceptible parent ICC 4991 (Pb 7) and an AB resistant parent ICCV 04516. The
resultant map consisted of 82 simple sequence repeat (SSR) markers and 2 expressed sequence tag (EST) markers covering 10
linkage groups, spanning a distance of 724.4 cM with an average marker density of 1 marker per 8.6 cM. Three quantitative
trait loci (QTLs) were identified that contributed to resistance to an Indian isolate of AB, based on the seedling and adult
plant reaction. QTL1 was mapped to LG3 linked to marker TR58 and explained 18.6% of the phenotypic variance (R
2) for AB resistance at the adult plant stage. QTL2 and QTL3 were both mapped to LG4 close to four SSR markers and accounted
for 7.7% and 9.3%, respectively, of the total phenotypic variance for AB resistance at seedling stage. The SSR markers which
flanked the AB QTLs were validated in a half-sib population derived from the same resistant parent ICCV 04516. Markers TA146
and TR20, linked to QTL2 were shown to be significantly associated with AB resistance at the seedling stage in this half-sib
population. The markers linked to these QTLs can be utilized in marker-assisted breeding for AB resistance in chickpea. 相似文献