【作者】 杨旭；

【导师】 邹志荣；

【作者基本信息】 西北农林科技大学 ， 蔬菜学， 2006， 博士

【摘要】 白菜(Brassica campestris L.)起源于中国,在我国蔬菜栽培中分布广、种植面积大。在我国北方白菜栽培中,春季的先期抽薹是生产上的主要限制因素。选育优良的晚抽薹品种,是其稳定、安全生产的重要保障。由于控制白菜的晚抽薹性状为数量性状,常规育种进展缓慢,只有通过QTL分析才能将多基因性状分解为若干遗传组分,找到与目标性状QTL位点紧密连锁的分子标记进行辅助选择,才能加快育种进程。本实验以结球白菜BY(Brassica campestris L. ssp. Pekinensis)和芜菁MM(Brassica rapa L. ssp. rapifera Metzg)杂交后代F1进行小孢子培养获得的81个DH株系为试材,采用AFLP、SRAP、RAPD、SSR及同工酶等5种标记技术,构建了一张较为饱和的、永久性的遗传图谱,在此基础上,进行耐抽薹性状及其相关农艺性状的QTL定位研究。利用白菜与芜菁杂交后代所获得的81个DH系组成的DH群体,发现AFLP、SRAP、SSR、RAPD和同工酶等5种标记均出现较高比例的偏分离,通过分子标记的分离分析发现,来源于两个亲本的标记座位在群体中的分离比例接近1:1;每个位点上,两个亲本基因频率的平均值比较接近,并没有发现有严重偏向某一亲本的现象,说明该群体总体上未出现严重的偏分离,可以用于遗传图谱的构建及数量性状QTL定位研究。以白菜与芜菁杂交后代所获得的81个DH系为作图群体,采用AFLP、SRAP、SSR、RAPD和同工酶等5种标记类型,利用JoinMap3.0软件构建了永久性高密度的白菜遗传连锁图谱。该图谱包含10个连锁群,由326个遗传标记组成,其中包括130个AFLP标记、123个SRAP标记、16个SSR标记、43个RAPD标记、12个同工酶标记。图谱总长度为882 cM,标记间平均图距为2.71 cM。每个连锁群上的标记数在6～118个之间,每个连锁群的长度在33～222 cM的范围内,平均图距在1.88～8.33 cM之间。该图谱是国内第一张结球白菜×芜菁亚种间永久性遗传连锁图谱,为耐抽薹等重要性状的基因定位、比较基因组学等研究打下了良好基础。利用MapQTL5软件,采用MQM作图法,对控制白菜耐抽薹性的数量性状基因位点进行了定位和遗传效应研究。以抽薹指数、抽薹日数、开花日数进行耐抽薹性表型鉴定,通过两个不同年份试验,共检测到控制耐抽薹性的QTL 18个,其中,控制抽薹指数的QTL 11个,控制抽薹日数QTL 3个、开花日数的QTL 4个,分布于4个连锁群上。获得控制白菜耐抽薹性较稳定的QTL共6个。其中,获得1个稳定的主效QTL,获得以抽薹指数、抽薹日数、开花日数3个指标定位共同稳定表达的QTL 1个,两个指标定更多还原

【Abstract】 Chinese cabbage (Brassica campestris L.)is one of the most important vegetables in East Asian countries, such as China, Japan and Korea. Early bolting of Chinese cabbage during spring cultivation often has detrimental effects on the yield and quality of the harvested products. Breeding late bolting varieties is a major objective of Chinese cabbage breeding programs.In order to analyze the genetic basis of bolting traits, a genetic map of Brassica campestris was constructed based on AFLP, SRAP, SSR, RAPD, and isozyme markers. Marker analysis was performed on 81 double haploid (DH) lines obtained by microspore culture from F1 progeny of two homozygous parents: BY (an extra-early bolting Chinese cabbage line) and MM (an extra-late bolting European turnip line).In this DH population, distorted segregation is a universal phenomenal. The frequency of distorted segregation markers were high. Out of 432 markers, the number of markers came from male parent and female parent agrees with the Mendel ratio 1:1 approximately. To single marker, the frequency of band from two parents was closely, and not deflected to either parent. It could be concluded that no obvious distorted segregation in the population.A total of 326 markers including 130 AFLPs, 123 SRAPs, 16 SSRs, 43 RAPDs and 14 isozymes were employed to construct a genetic linkage map with 10 linkage groups,which covered a total of 882 cM with an average distance of 2.71 cM between loci. Number of markers in every linkage groups varied from 6 to 118, average interval distance from 1.88 cM to 8.33 cM and the total map distance from 33 to 222 cM. A total of 25.2% deviated markers distributed in the map. The genetic map is fundamental for gene localization, comparative genomics, and QTL mapping of bolting and agronomical traits.The bolting resistance of each DH line were evaluated by bolting index, bolting time and flowering time under controlled conditions. QTL analysis was conducted using MQM mapping with MapQTL5 software. In 2005 and 2006,twenty-one QTL controlling bolting resistance were identified,11 for bolting index, 3 for bolting time, 4 for flowering time. These QTL, accounting for 10.7% to 35% of the phenotypic variation with positive additive effects, were distributed into five linkage groups. BI-5 had the highest contribution to bolting resistance, and it may be a major QTL. These results provide useful information for molecular更多还原