【作者】 刘霞；

【导师】 徐爱遐； 黄镇；

【作者基本信息】 西北农林科技大学 ， 作物学， 2018， 硕士

【摘要】 油菜在国民生产、居民生活中发挥着主要作用。株高是影响油菜产量、抗逆性尤其是抗倒伏性的重要因素,开花时间是影响油菜成熟期、产量等的另一重要因素。近年来油菜品种的株高和熟期已经成为制约油菜产业发展的关键因子,生产上急需株高较矮且早熟的适机收的品种,因此深入开展株高和开花期的遗传和基因研究具有重大的理论和实践意义。本研究分别利用甘蓝型油菜的高代自交系构建了两个“高×矮”杂交组合:“YG-1×72-27-1-2”和“HN92×74-1002”,其中“YG-1×72-27-1-2”又是一“晚花×早花”组合。2016-2018年分别将两个组合的6世代群体（P₁、P₂、F₁、F₂、B₁和B₂）以及“YG-1×72-27-1-2”组合的F_2:3家系种植于杨凌和三原两地,进行开花时间的记录,并于成熟期进行株高及其相关性状的测量,研究结果如下:1.应用主基因+多基因混合遗传分离分析方法,对甘蓝型油菜株高及其相关性状进行研究,并估计其遗传效应。结果表明:“YG-1×72-27-1-2”组合株高（PH）及其相关性状主要受2对主基因控制,部分性状有多基因效应的存在;“HN92×74-1002”组合PH、一次有效分枝高度（VBH）、主花序长度（MIL）和有效分枝数（BN）的遗传可能受2对主基因控制,部分性状存在多基因效应;有效分枝节间距（IL）的遗传可能受加性-显性-上位性多基因控制。在分离世代群体（B₁、B₂和F₂）中,“YG-1×72-27-1-2”组合的5个性状的平均主基因+多基因遗传率中等偏上,介于42.58%-67.94%之间;在“HN92×74-1002”组合中,PH、VBH和MIL的平均主基因+多基因遗传率中等偏上,介于44.09%-77.27%之间,IL和BN的主基因+多基因遗传率偏低,分离世代平均遗传率介于15.24%-25.09%。两个杂交组合中,PH的遗传率均最高,因此,在进行甘蓝型油菜理想株高育种进程中,在早代对株高进行选择是有效的。2.对杨凌和三原两点甘蓝型油菜杂交组合“YG-1×72-27-1-2”、“HN92×74-1002”形成的6世代群体的株高及其相关性状进行相关性分析,结果表明:PH与VBH、MIL及IL呈极显著正相关,VBH与BN呈极显著负相关,MIL与BN和IL呈极显著正相关。这说明随着株高的增加,一次有效分枝高度升高,主花序和一次有效分枝节间距伸长;一次有效分枝高度的增加会导致有效分枝数减少;随着主花序的伸长,有效分枝节间距伸长。因此,在进行甘蓝型油菜适宜株高选育进程中,认为一次有效分枝高度、主花序长度和有效分枝节间距可作为株高相关性状进行辅助选择。3.以“YG-1×72-27-1-2”组合的F₂世代（170株）为作图群体,利用1030对SSR引物对双亲进行多态性筛选,筛选出119对在双亲间存在多态性的引物,占引物总数的11.55%。利用119对差异性引物进行F₂群体的多态性筛选,结果107对引物在群体中重复检测出多态性,多态率为89.92%,获得带型清晰的标记位点160个。利用JoinMap4.0对该群体的160个多态性SSR标记进行连锁性分析,构建了一张包含18个连锁群的甘蓝型油菜遗传连锁图谱,SSR标记覆盖总长为900.33cM,平均遗传距离为8.50cM。4.对“YG-1×72-27-1-2”组合三个环境下株高、株高相关性状及开花时间进行相关性状的QTL分析。结果表明,共检测到20个QTL位点,其中,15个QTL与株高及其相关性状有关,包括3个株高QTLs、2个一次有效分枝高度QTLs、6个主花序长度QTLs、1个有效分枝节间距QTL和3个有效分枝数QTLs。在LG1、LG2和LG15上均检测到一个株高及其相关性状的QTL重复区域。与开花时间有关的QTL位点有5个。20个QTL位点的LOD值介于2.93-6.05之间,表型变异介于0-21.75%之间,其中,qMILYL-3和qMILYL-2分别可解释表型变异的21.75%、19.17%,为主效QTL。在qMILYL-2和qBN-2形成的QTL重复区域初步筛选了两个候选基因Bra025720和Bra025910。更多还原

【Abstract】 Rapeseed plays a major role in national production and resident life.Plant height(PH)is one of the key factors of its yield and resistance,especially the lodging resistance.Flowering time(FT)is another factor affecting the maturity and yield of rapeseed as well.PH and maturing period of rapeseed varieties have become key factors restricting the development of rapeseed industry in recent years.So the varieties with shorter height and earlier maturity are badly needed in the actual production.Therefore,it is of great significance to carry out genetic research on plant height and flowering period in Brassica napus L..In this study,two combinations “YG-1×72-27-1-2” and “HN92 ×74-1002”,were constructed from inbred lines of Brassica napus L..There was significant difference on flowering time of “YG-1×72-27-1-2”.Six generations(P1,P2,F1,F2,B1 and B2)derived from two crosses and F2:3 family from “YG-1×72-27-1-2” were planted in Yangling and Sanyuan respectively from 2016 to 2018.FT was recorded and PH with its related traits were measured in the mature stage.Results were as follows:1.The inheritances of PH and its related indicators were analyzed by mixed major gene plus poly-gene genetic model.Results showed that PH and its related traits of “YG-1×72-27-1-2” were controlled by two pairs of major gene.There were poly-gene effect in some indicators.In cross of “HN92×74-1002”,PH,the first valid branch height(VBH),main inflorescence length(MIL)and numbers of valid branch(BN)were dominated by two pairs of major gene.There were poly-gene effect in some traits while internodal length(IL)was dominated by poly-gene with additive-dominant-epistatic effect.The heritabilities among segregating generations(B1,B2 and F2)of five traits in “YG-1×72-27-1-2” were medium,which were between 42.58% to 67.94%.As for “HN92×74-1002”,the heritabilities of PH,VBH and MIL were between 44.09% to 77.27% while the heritabilities of IL and BN were between 15.24% to 25.09% only.The heritability of PH reached the highest in both crosses.Thus,the selection of plant height was effective in early generation on the breeding process of ideal plant height in Brassica napus L..2.The correlation analysis of PH related traits on “YG-1×72-27-1-2” and “HN92×74-100 2” showed that PH was significantly and positively correlated with VBH,MIL and IL.VBH was significantly and positively correlated with BN,and MIL was significantly and negatively correlated with IL.The results suggested that with the increasing of plant height,length of first valid branch,main inflorescence and internode length increased accordingly.The raise of first valid branch might lead to the decrease of branch numbers,and the add of main inflorescence result in the increase of internodal length.Therefore,VBH,MIL,IL and BN could be regarded as the relevant traits in the breeding process for suitable rapeseed height.3.The F2 population with 170 individuals derived from “YG-1×72-27-1-2” was used as test materials for mapping.1030 pairs of SSR primers were used to screened with polymorphism between parental lines and 119 pairs of primers were selected to be polymorphisms among parents,which accounted for 11.55% of all.The polymorphic analysis of F2 population was conducted by 119 pairs of differential primers,polymorphism could be detected repeatedly through 107 pairs of primers,and the polymorphism rate was 89.92%.160 marked sites with clear bands were obtained and were clustered into 18 linkage groups spanning 900.33 c M in length with a distance between the adjacent markers of 8.50 c M on average.4.The QTL analysis of PH relevant traits and flowering time was made basing on data from F2 population planted in Yangling(2017)and F2:3 families planted in Yangling and Sanyuan(2018).20 QTLs were detected in our study,including 15 QTLs of plant height relevant traits and 5 QTLs of flowering time.15 QTLs of PH related traits were composed of 3 QTLs of PH,2 QTLs of VBH,6 QTLs of MIL,1 QTL of IL and 3 QTLs of BN.A QTL repeat region,which was related to PH and its relevant indicators,was detected in linkage 1,2 and 5 respectively.The LOD score of 20 QTLs ranged from 2.54 to 5.87 and phenotypic variation explained by the single putative QTL varied largely from 0 to 21.75%.q MILYL-3 and q MILYL-2 were characterized by major QTL while the phenotypic variation of q MILYL-3 and q MILYL-2 was 21.75% and 19.17% respectively.Two candidate genes,Bra025720 and Bra025910,were detected in the repeat region of q MILYL-2 and q BN-2.更多还原