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.