用小麦族7个部分同源群的40个RFLP探针对小麦一纤毛鹅观草二体附加系进行分析，在证实了原有细胞学鉴定结果的基础上，又进一步提供了纤毛鹅观草染色体部分源群的分子证据。即96K025、96K026中添加的一对纤毛鹅观草染色体B属于第2部分同源群；96K012、96K013中添加的一对染色体E属于第5部分同源群。对以上株系的衍生株系分析结果表明，染色体B、E在后代中可稳定传递。96K030中添加的一对染色体D与染色体B同属第2部分同源群。端二体附加系96K033所添加的纤毛鹅观草染色体B的一条臂，只与第2群短臂探针有杂交信号，从而初步确定其可能与小麦族第2部分同源群短臂同源。而另一条臂则与第2群长臂同源。

以簇毛麦（Haynaldia villosa（L.）Schur）物种专化重复序列探针pHv62及小麦（Triticum aestivum L.）第六部分同源群短臂专化RFLP探针Psr113对扬94-138（“扬麦158”的改良品系）与易位系92R149 配制的F2群体进行分析，观察到易位系中的6V短臂在杂交后代中的传递率为69. 5%，接近75%的理论值。对来自同一个F1的另外147株F2 群体以6个白粉菌菌株进行苗期抗病性测定，检测结果表明6VS上所携Pm21基因在向“扬麦158”小麦基因型转移时，按显性单基因遗传，并能很好地表达。

从亲缘植物向小麦品种转移抗病性已成为小麦抗病育种中解决种内基因资源贫乏和抗源单一化问题的一种重要途径。本文在回顾小麦通过染色体工程转移外源抗病性历史的基础上，介绍了南京农业大学细胞遗传研究所近lO多年来，从亲缘植物中寻找、鉴定与转移白粉病和赤霉病抗性的研究过程中所取得的成果。其中特别侧重介绍了该所在综合应用有利于精确鉴定外源染色体或其片段的各种方法技术方面的经验体会。

Pm6 in bread wheat (Triticum aestivan I.), which was transferred from Trition,timpopheevii L, is a gene confering resistance to the powdery midew disase casued by Erysiphe granints f. sp. Tritici, Six near-isogenie lines (XILS) of Pm6 in a cultivar Prins background were analyzed to map this gene using restriction fragment length polymorphism (RFFLP). Each of the six NILs posscssed a T. timophecvii-derived scgment, varying in length, and associated with powdery midex resistance, Lines IGVI-465 (FAO163h/7*Prins) and IGVI-467 DAED 59B/7*Prins) had the shortest introgressed scgmetns. whith weere delected only by DNA probes BCD 135 and PSR934. respectively. The polymorphic loci detected by both probes were mapped to the long and of chromosomc 2B. Lines IGVI-458 C (CII 259/8*Prins) contained the longest T. timopheevii segmets involving both arms of donor chromosome 2G aetoss the centromere, All these introgressed segments had an overlapping region flanked by the loci xpsr934 and xbed135 on 2BL Thus, Pm6 was located in this region since the powdery midew resistance in all the NILs resulted from the introgressed fragment, Lising the F, mapping population from a cross of IGVI-463 (PII70914/7*Prins, Pm6 was shown to be closely linked to the loci xbcd135 and xbed 266 at a genctic distance of 1.6cM and 4.8cM, respectively, BCD135 was sucessully used detecting teh presence of Pm6 in different genetic hackgrounds.

Breeding durable resistance ot pathogens and pests is a major task for modern plant breeders and pyramiding different resistance genes into a genotype is one way of achieving this. Three powdery midew resistance gene combinations, Pm2+Pm4a, Pm2+Pm21, Pm4a+Pm21 were successfuly integrated into an clite wheal cultivar Yang158, Doublc homozygotes were selected from a small F2 population with the help of molccular markers, As the parents were near-isogenic lines (NILs) of Yang158. the progenies showed good uniformity in morphologicaland other ono-resistance agromic traits. The present work illustrates the bright prospects for the untilization of molecualr makrers in brceding for host resitance.

A spceies-specific repeated sequence, pHvN-AU62, was cloned from Haynaldia villosa, a wheat relative of grea improtance, It strongly hybridized to H. Villosa, but not to wheat. In situ hybridization ocalized this sequence to six of seven H. villosa chromosome pairs in iclomeric or sub-telomeric regions, Southern hybridization to wheat-H, villosa additon lines that chromosomes 1V through 6V escaped detection, In addition to H. villosa, several Triticeae species were identified for a high aboundance of the PHvNAU62 repeated sequence, among which Thinopyrum hassurabicum and Leymus racemosus produced the strogest signals. Scquence analysis indicated that the cloned fragment was 292 bp long, being AT rich (61%). and showed 67% homology of pSc 7235, a rye re[eated scquence. Isochizomer analysis suggestedthat the present repeated sequence was heavily methylated at the cylosine of the CpG dimer in the genome of H. cillosa. It was also demonstrated that pHvNAU62 is useful in tagging the introduced 6VS chromosome arm. which confers a resistance gene to wheat powdery mildew, in the segregating generations.

系统总结了南京农业大学细胞遗传研究所近20多年来利用基因组分析方法培育从簇毛麦（aynaldia villosa Sch.）、大赖草（Leymus racemosus Lam.）、鹅观草（Roegneria kamoji C. Koch）和纤毛鹅观草（R. ciliaris (Trin.）Nevski）导入白粉病和赤霉病抗性的小麦种质的研究进展。利用染色体C-分带、基因组原位杂交、分子标记（特别是RFLP）等技术与非整倍体分析相结合对所创制的种质进行了系统分析与鉴定。还对所培育的小麦种质在育种实践和理论研究中的潜在价值及相关问题进行了讨论。

以当地育成的小麦抗白粉病材料，对国外筛选到的与白粉病抗性基因Pm2及Pm4a紧密连锁的RFLP标记进行了分析。结果表明，这些RFLP标记即使在遗传背景不同的情况下仍可用于对Pm2及Pm4a基因的检测及鉴定。研究还表明，利用分子标记辅助小麦抗白粉病育种不仅可行，而且还可对育成的抗病品系所携具体抗性基因进行精确鉴定，并可大量减少分菌系或小种接种鉴定时的冗繁程序。

借助与Pm2及Pm4紧密连锁的RFLP标记，对南京农业大学细胞遗传所与江苏省里下河地区农科所合作育成的抗白粉病小麦新品系及其它单位育成或引自国外但所含具体Pm基因尚有异议的抗病品种进行了分析。结果表明，本所与江苏省里下河地区农科所合作育成的抗病新品系及江苏省农科院育成的白粉病抗源材料中所含具体Pm基因与按系谱推导及对白粉病菌抗谱分析的结果相一致。而据单体分析认定为“Pm 2x ”和“KG”（6A）的白免3号和肯贵阿1号和按侵染型推导为含Pm2+ 6的“郑州831”，在本研究中发现这3个材料所含主效抗病基因均为Pm4，而无Pm2，此结果与分菌系、分小种抗谱鉴定结果相符。另外，RFLP分析还证明了2个引自国外且抗病性已降低的Pm6鉴别寄主Timgalen 和CI12632ö8Cc所携带Pm6基因已丢失。

用抗白粉病的普通小麦一簇毛麦6VS/6AL易位系与普通小麦品种扬麦5号、普通小麦一簇毛麦6v代换系和中国春6A双端二体以及6V代换系和6A双端二体配制了4个测交组合，分析了这4个杂交组合F1 PMC's MI C-分带的减数分裂构型。在（6VS/6AL易位系×扬麦5号）和（6VS/6AL易位系×6V代换系）的F1 PMC's MI，分别观察到由易位染色体与6A染色体和6v染色体配对形成的具有特定C-分带带型的棒状二价体，杂种中的棒状二价体数目高于各自亲本中的棒状二价体数。在（易位系×C.S.d.d.t 6A）F1中，在87.9%的PMC中观察到由易位染色体长臂与6AL端体配对形成的异形二价体（tl”）。而在（6V代换系×C.S.d.d.t 6A）F1中，96.68%的PMC具有两个单价端体（t',t'）。该结果进一步证实易位涉及簇毛麦染色体6VS和小麦染色体6AL，易位断点靠近着丝粒。在减数分裂中，易位染色体的正常配对和分离，保证了6VS上白粉病抗性基因Pm21的正常传递，为这一新抗源在小麦育种中的应用奠定了细胞学基础。