【作者】 秦鸿德；

【导师】 张天真；

【作者基本信息】 南京农业大学 ， 遗传学， 2007， 博士

【摘要】 棉花是世界上最重要的天然纤维作物,也是重要的油料作物之一。自上世纪90年代以来,我国棉花育种进入了一个利用杂种优势的新时期。分子标记技术的发展,为杂种优势的理论研究和实际应用提供了强有力的手段。筛选到与目的性状中的主效基因紧密连锁的分子标记进行辅助选择,可大大提高育种效率,对快速同步改良作物的产量、品质、抗病虫性状具有重要意义。但由于陆地棉的遗传基础狭窄,品种间的遗传多态性低,目前还没有较高覆盖率的陆地棉品种间的分子标记遗传图谱。利用陆地棉品种间的组合定位QTL时,搜索空间只占棉花全基因组的一小部分,定位结果用于辅助选择时常有力不从心之感。而且在棉花育种中,常规育种手段的选择效率普遍偏低。本文旨在利用分子标记技术和两个多亲本分离群体,构建具有较高覆盖率的陆地棉品种间的分子标记遗传图谱,并用以分析发掘湘杂棉2号、皖杂40、中棉所28以及南抗3号等几个在我国长江流域和黄河流域大面积推广种植的优良杂交组合的亲本中与产量和纤维品质相关的数量性状基因位点。用轮回选择的方法,在两个与QTL定位群体来源相同基础群体间进行特殊配合力相互轮回选择,打破各产量构成因素间、高产与优质以及高产与抗逆基因间的不利连锁,充分聚合产量杂种优势建成基因;并用QTL定位结果在基础群体和改良群体中进行分子标记辅助选择提高育种效率,加速育种进程,进一步改良亲本群体,选出含有更多产量杂种优势建成基因的优秀亲本,以培育出具有更高杂种优势的优良杂交组合。1.用湘杂棉2号、皖杂40、中棉所28以及南抗3号中源于长江流域棉区的亲本构建了一个四交群体（泗棉3号/苏棉12//中4133/8891）及其F_2:3家系,利用SSR标记和JOINMAP3.0软件构建了一张陆地棉四交群体品种间的分子标记遗传图谱。该图谱总长为2113.3cM、含有286个多态位点、覆盖率达42.3%。该图谱由56个连锁群组成,其中51个连锁群被定位到26条染色体上。单个连锁群上的标记数从2个到24个,平均5.2个;长度从0.37 cM到125 cM,平均38.4 cM。A亚组由24个连锁群组成,总长度为808.4cM、含有125个多态位点,标记间的距离平均为6.5 cM;D亚组由27个连锁群组成,总长为1231.6cM、含有150个多态位点,标记间的距离平均为8.2 cM。F测验表明A、D亚组间的标记数没有明显差异,D亚组的标记间的平均距离大于A亚组。5个连锁群未被安排到任何染色体。整个图谱标记间的距离平均为7.4 cM。利用四交群体F_2:3家系的两年表型数据,用MAPQTL5.0对株高、果枝、叶绿素含量、光合速率、现蕾期等5个农艺与生理性状,单株铃数、铃重、衣分、每铃种子数、籽指、衣指、籽棉产量、皮棉产量等8个产量性状及产量构成因素,纤维长度、纤维强度、麦克隆值、伸长率和整齐度等5个纤维品质性状等共18个性状进行了QTL定位。共检测到14个控制农艺与生理性状的可能性QTL和2个显著性QTL,解释的表型变异从4.0%-19.4%;检测到31个控制产量性状及产量构成因素的QTL,其中5个为显著性QTL,26个为可能性QTL,解释的表型变异从3.3%-30.5%;检测到28个控制纤维品质性状的QTL,其中9个为显著性QTL,19个为可能性QTL,解释的表型变异从4.6%-25.8%。在所有QTL中,qSI-1、qLP-1、qFL-2、qFM-1、qFL-5和qFL-4等6个QTL与前人研究的结果一致。21个QTL均可在一年的单独分析中或两年的平均数分析中检测到,而且位置和效应方向相同或大致相同。这些表现出不依赖于环境的稳定性QTL,可应用于标记辅助选择。2.用湘杂棉2号、皖杂40、中棉所28中源于黄河流域棉区的亲本和一个栽培品种构建了一个三交群体（164/中12//低酚棉8号）,利用JOINMAP3.0构建了一张三交群体品种间的遗传图谱。该图谱总长为940.1cM、含有107个多态位点、覆盖率18.8%,两多态位点间的平均遗传距离为8.8 cM。图谱由29个连锁群组成,26个连锁群被定位到19条染色体上。单个连锁群的长度从1.1 cM到85.9 cM,平均32.4 cM。利用三交群体F_2:3家系的两年表型数据,共检测到6个与果枝、叶绿素含量、光合速率、现蕾期相关的QTL,解释的表型变异从3.2%到5.6%。检测到15个与单株铃数、铃重、衣分、每铃种子数、籽指、籽棉产量、皮棉产量等产量性状及产量构成因素相关的QTL,其中6个为显著性QTL,9个为可能性QTL,解释的表型变异从2.6%到11.0%。检测到8个与纤维长度、麦克隆值、伸长率和整齐度等纤维品质性状相关的QTL,其中3个为显著性QTL,5个为可能性QTL,解释的表型变异从3.2%到6.8%。3.经过一轮群体间特殊配合力相互轮回选择后,群体的产量性状大多有显著改良,平均数提高,增幅从1.96%到26.99%不等。群体的表型性状的变异幅度没有下降,分子标记分析的结果也显示群体的遗传多样性得到保持,甚至有一定程度的提高。在经过多代自交和杂交的轮回选择群体中,用与QTL连锁的单标记和两侧标记进行言袷?仍然有较好的效果。在长江流域群体中聚合衣分和铃重的QTL时,同时选择两个QTL的效果明显优于每次只对一个QTL进行选择的效果。在黄河流域群体中聚合衣分和铃重的QTL时,同时选择的衣分QTL的个数对选择效果有显著影响,选择的QTL数目越多,表型值越高;但同时选择铃重QTL的个数则对选择效果没有明显影响。利用这些与OTL连锁的分子标记在植株开花前进行标记选择,在开花前就可以选出优良单株进行下一轮的测交,不必等到吐絮后进行表型选择后再确定下一轮测交的单株,可将轮回选择的程序减少一季;或者说减少当季随机选株测交的盲目性,提高了选择效率。更多还原

【Abstract】 Cotton is the most important textile fiber crop and the world’s second-most important oil-seed crop after soybean.Since the 90’s of last century,the breeding of Upland cotton （Gossypium hirsutum L.） cultivars had step into a new period characterized with ultility of heterosis in China.The developments on molecular marker technology offer plant breeders a powerful tool to understand genetic basis of heterosis and make use of it in breeding. Especially,if the marker tightly linked with major gene controlling interesting traits was identified,selection assisted with the marker will improve the efficiency of selection for improving cultivars for yield,products quality,pest resistance,etc.No genetic linkage map derived from upland cotton cultivars and coverd most cotton genome was reported because of their narrow genetic basis and low genetic polymorphism. Only a fraction of the cotton genome was exploited when these crosses derived from upland cotton cultivars were used to QTL mapping,and the results of QTL mapping was not valuable for MAS.Classic selection methods were low power for cotton breedingIn this paper,molecular markers and segregated populations derived from more paprents than two were used to develop genetic linkage map and to exploit QTLs concerned with yield and fiber quality.These parents were also parents of four hybrids,Xiangzamian2, Wanza40,Zhongza028 and Nankang3 which were popularized hybrids in the Changjiang River valley and in the Huanghe River valley.For the popurse of pyramiding more super genes,specific combining ability reciprocal recurrent selection method was used to break down linkage-drag among yield components,and high yield and low fiber quality between two initial populations derived from the same parents was used for QTL mapping populations.MAS was conducted with QTL mapping results to accelerate the procedure of populations improvement,and pick out materials pyramided more super genes for the hybrid breeding during the specific combining ability reciprocal recurrent selection procedure.The results are followed:1.A four-way cross segregated population,Simian3/Sumian12//Zhong4133/8891,and its F_2:3 inbreed lines were constructed.The four materials Simian3,Sumian12,Zhong4133 and 8891,which originated from Changjiang River valley,were the parents of the elit hybrids Xiangzamian2,Wanza40,Zhongza028 and Nankang3.A linkage map was developed for the four-way cross with SSR markers and JOINMAP3.0 software.The map is comprised of 55 linkage groups with 286 mapped loci which span between 0.37cM and 125cM.The 286 loci covered 2113.3cM,which was approximately 42%of the total recombination length of the cotton genome.The average distance between loci was 7.4cM genome wide.Twenty four linkage groups were assigned to A-subgenome,contain 126 loci and span 808.4cM and 27 linkage groups were assigned to D-subgenome,contain 152 loci and span 1231.6cM.The average distance between loci was 6.4cM in A-subgenome and 8.1cM in D-subgenome.Five remained linkage groups were failed to be assigned to any chromosomeIn the four-way cross population,QTLs concerned with plant architecture and physiology traits included plant height,plant branches,leaf chlorophyll content, photosynthetic rates and date of first square,and yield and yield components traits involved number of bolls per plant,boll weight,lint percent,number of seeds per boll,seed index, lint index,seed cotton yield per plant and lint yield per plant,and fiber quality traits,such as fiber length,fiber strength,micronaire reading,fiber elongation ratio and fiber uniformity were detected with MAPQTL5.0.Fourteen suggestive QTLs and two significant QTLs controlled plant architecture and physiology traits were detected with explained 4.0% to 19.4%of the phenotypic variation.Twenty six suggestive QTLs and five significant QTLs concerned with yield and yield components traits were detected with explained 3.3% to 30.5%of the phenotypic variation.Nineteen suggestive QTLs and nine significant QTLs concerned with fiber quality traits were detected with explained 4.6%to 25.8%of the phenotypic variation.Out of all QTLs,qSI-1、qLP-1、qFL-2、qFM-1、qFL-5 and qFL-4 were also reported in previously research.Twenty one QTLs were detected in same location/interval or nearby at same loci and with same effects direction in separate analysis and joint analysis.These QTLs with little interaction by environment and stable in different environments are of value for a marker-assisted selection（MAS） program2.A three-way cross segregated population,Zhong164/Zhong12//Difenmian8,and its F_2:3 inbreed lines were constructed.Zhong12 and Difenmian8 were parents of three hybrids, Xiangzamian2,Wanza40 and Zhongza028,and originated from Huanghe River valley.A linkage map was developed for the four-way cross with SSR markers and JOINMAP3.0 software.A linkage map was constructed for the four-way cross with JOINMAP3.0.The map is comprised of 29 linkage groups with 107 mapped loci which span between 1.1cM and 85.9cM.The 107 loci covered 940.1cM,which was approximately 18.8%of the total recombination length of the cotton genome.The average distance between loci was 8.8cM genome wideIn the four-way cross population,Six suggestive QTLs controlled plant branches,leaf chlorophyll content and date of first square were detected with explained 3.2%to 5.6%of the phenotypic variation.Nine suggestive QTLs and six significant QTLs concerned with number of bolls per plant,boll weight,lint percent,number of seeds per boll,seed index, seed cotton yield per plant and lint yield per plant were detected with explained 2.6%to 11.0%of the phenotypic variation.Five suggestive QTLs and three significant QTLs concerned with fiber length,micronaire reading,fiber elongation ratio and fiber uniformity were detected with explained 3.2%to 6.8%of the phenotypic variation.3.After one cycle specific combining ability reciprocal recurrent selection,the means of yield traits of two populations were significantly increased with extent from 1.96%to 26.99%.The range of variation of yield traits was not seen decrease in two improved populations.The data from molecular marker analysis also showed that the genetic variety of improved populations did not decrease than initial populations,and even was increased in some degree.Although recurrent selection populations aroused from primary segregated population of three or four-way cross by many times inbreed and outbreed,selection with single marker or flanking markers were still effective.Means of individuals contained two QTLs were significant higher than that of contained one QTLs when pyramid QTLs of lint percent or boll weight in PⅠ.Means of lint percent of individuals will significantly increase with the number of QTL increase in individuals when pyramid QTLs of lint percent or boll weight in PⅡ.But the same case can not be seen when pyramid QTLs of boll weightAssisted with markers linked with QTL,selected individuals to test-cross for next cycle recurrent selection can be done before flowering instead of after boll opening,and can accelerate the procedure of recurrent selection,or conduct test-cross before flowering with distinct goal and more efficacies.更多还原