黄瓜的分子标记和连锁图谱研究进展

黄瓜分子标记和遗传连锁图谱的研究工作相对番茄、小麦等作物比较落后，至今开展的分子标记研究多围绕黄瓜遗传关系分析进行，现有的几张遗传连锁图谱基本是由美国Staub研究小组完成，已被定位在图谱上的同工酶、RAPD、RFLP、SSR、AFLP等标记总数达到300多个，各标记间平均距离达到2.1cM，被整合在一起的遗传基因不足10个(F、B、de、ll、dm)。     

水稻品种02428和8504的广亲和性遗传

 以02428、8504和CPSLO 17与籼型测验种南京11、IR36、测49和粳型测验种巴利拉、秋光、丰锦测交，F1杂种的小穗育性为78.8%～97.9%，其平均值02428为90.2%，8504为82．4%，CPSLO 17为90.9%。以CPSLO 17作对照，研究了02428、8504的广亲和性遗传，推测它们的广亲和性遗传都是由一对主基因控制的，广亲和基因与色素原基因C+连锁位于第Ⅰ连锁群上，遗传规律符合单位点孢子体-配子体互作模式，并受微效基因的修饰作用。     

家蚕新突变型h斑油基因的连锁定位研究

新近自保存系统中发现的油蚕突变———h斑油 (mottledtranslucentoh)的性状特征为 :幼虫体表遍布不透明的白色斑块 ,大小不一 ,其余部分为低度透明。通过与正常型和各连锁群标志基因系杂交 ,进行遗传分析和连锁检索 ,结果 :h斑油为第 2 0连锁群的隐性突变 ;与霜降油蚕 (oh)的杂交结果确定其基因座位为 (2 0 0 .0 ) ,对霜降油为显性。命名其基因符号为ohm。同时发现ohm 对中国油 (oc)表现上位作用。     

家蚕Jc油蚕基因的发现和连锁分析

在蚕品种东3291选育过程中．发现了一种中等透明度的油蚕突变，其在第1龄眠中死亡率约为21．16％。经遗传和连锁分析表明：该油蚕性状受一对隐性基因控制，基因位于第5连锁群，且与该连锁群的其它油蚕基因不同，是一个新的油蚕突变，命名为Jc油蚕（JcTranslucent），基因记号：ojc。     

A Genetic Linkage Map of Brassica rapa Based on AFLP Markers

A F2 mapping population was developed by crossing a Chinese cabbage-pe-tsai variety CC156 and an oil type Rapid cycling RC144 which were different from each other in morphology, maturity, self-compatibility, plant height, etc. Using 244 AFLP markers a map was constructed containing 10 main linkage groups covering a total distance of 857 cM,corresponding to 3.5 cM per marker. Length of linkage groups varied from 43 to 125 cM and the number of AFLP markers linkage to each group ranged from 7 to 41.     

小麦BNS雄性不育基因连锁群分析和主效QTLs初步定位

为初步定位小麦温敏雄性不育系BNS中与不育相关的QTL及其所属连锁群,用BNS及其完全保持系郑麦366的F₂为作图群体,建立自交结实率和花粉可育率两个表型BSA池,选用均匀分布在小麦染色体上的710个SSR分子标记,在BSA池中筛选连锁标记,并进行QTL定位,同时用连锁标记引物在BNS DNA中重扩增,扩增产物序列在小麦基因组中进行比对,验证标记所属染色体并分子定位。结果表明,在2对BSA池中共筛选到12个连锁标记,涉及8个连锁群。单标记分析发现,5个连锁标记（Xwmc396、Xwmc517、Xbarc55、Xwmc332和Xwmc752）与不育QTL紧密连锁。用区间分析法分析发现,有2个主效不育QTL,分别为2B染色体上的 qBS1 （紧密连锁Xwmc332和Xbarc55）和7B染色体上的 qBS2 （紧密连锁Xwmc396和Xwmc517）。两个主效QTL的LOD值均大于5,贡献率均大于13%,且显性效应均大于加性效应。     

小麦ARz抗纹枯病的QTL定位研究

纹枯病在我国已成为影响小麦高产、稳产的主要病害之一。为了确定小麦纹枯病抗性基因的位点和数量，本文以单粒传(SSD)方法构建了ARx和扬麦158杂交的F6代重组自交系(RIL)的遗传群体共137个单株，分别在2002和2003年用牙签法和沟带接菌法进行了3次纹枯病抗性鉴定。初步研究结果表明．小麦纹枯病抗性是由主效基因和微效多基因共同控制的。在2D、3A、3B、3D、7D等5条染色体上分析了42个SSR引物．共49个位点．结合回归分析找到10个SSR分子标记。综合本项目组先前分析的48个SSR标记住点．分别对2、3、7同源群使用Map Manager QTXbl7建立了14条连锁区段，并用区间作图法检测到与小麦纹枯病抗病相关的6个QTLs，位于2D、3D、3B和7D上．单个位点可分别解释表型变异方差的9．0％、7．0％、7．0％、9．0％、14．0％和8.0％。初步认为在7D上有一个抗小麦纹枯病的主效QTL。     

Identification of RAPD Markers and Development of SCAR Markers Linked to a Powdery Mildew Resistance Gene,and their Location on Chromosome in Wheat Cultivar Brock

Abstract

Wheat cultivar Jing 411 which is susceptible to powdery mildew, and wheat cultivar Brock and NILs of Jing 411, which are resistant to powdery mildew were analysized for polymophisms using 213 random amplified polymorphic DNA primers. Only one primer (S2092) stably produced a polymorphic band between the resistant and susceptible plants. Linkage analysis of this marker (S2092₉₇₂) revealed that the polymorphism existed in a 131 F₂ segregating population. S2092₉₇₂ was closely linked to a powdery mildew resistance gene in wheat cultivar Brock, at a linkage distance was 4.9 cM. S2092₉₇₂ was converted to sequence characterized amplified region (SCAR) markers SCAR₈₆₀ and SCAR₂₀₀. The two SCAR markers were used for detecting F₂ segregating population. SCAR₈₆₀ and SCAR₂₀₀ existed in resistant plants but were absent in the susceptible plants. We concluded that S2092₉₇₂ was located on the chromosome 3BL. These markers will be useful for marker-assisted selection and gene pyramiding in wheat resistance breeding.     

Development of rice introgression lines with brown planthopper resistance and KDML105 grain quality characteristics through marker-assisted selection

‘Khao Dawk Mali 105’ (KDML105), a Thai aromatic rice cultivar, has been accepted in markets as a prime jasmine rice with premium prices. It has been extensively used as a parental line to develop new cultivars for rainfed lowland areas in Thailand because of its favorable quality and fragrance. However, this cultivar is highly susceptible to brown planthopper (BPH), a phloem sap-feeding insect pest of rice. The main objective of this study was to combine KDML105 essential grain quality traits with BPH resistance from the donor cultivar, ‘Rathu Heenati’. The linkage drag between Bph3 and Wx^a alleles was successfully broken by phenotypic and marker-assisted selections. All introgression lines (ILs) developed in this study showed a broad spectrum resistance against BPH populations in Thailand and had KDML105 grain quality standards. Finally this study was revealed that the ILs can be directly developed into BPH resistant varieties or can be used as genetic resources of BPH resistance to improve rice varieties with the Wx^b allele in rice breeding programs.