导入小麦的外源染色体片段的准确鉴定及外源抗性基因的稳定性分析

Precise Identification of Alien Chromosome Segment Introduced in Wheat and the Stability of Its Resistance Gene

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Ｆ１ＰＭＣ’ｓＭＩＣ－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Ｆ１ＰＭＣ’ｓＭＩ，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．ｔ６Ａ）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．ｔ６Ａ）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。

The C-banded meiotic configurations at MI of PMCs were investigated in F1 hybrids of a translocation line with Yangmai 5, 6V substitution line and double ditelosomic 6A of Chinese Spring(C.S.d.d.t 6A),as well as in the F_1 hybrid of 6V substitution line with C.S.d.d.t 6A, The bivalents with specific C-banding patterns formed by translocated chromosome and chromosome 6A or 6V were observed in(translocation line×Yangmai 5or 6V substitution line)F1 plants,with more rod bivalent per PMC in F1 plants than in their parents.The(tl”,t’)configurations were observed in 87.9% of PMCs in(translocation line×C.S.d.d.t. 6A) F1 plants.Meiotic C-banding analysis revealed that the long arm of translocated chromosome and telocentrics 6AL were involved in the formation of heteromorphic bivalent(tl”).But in(Sub.6V×C.S.d.d.t. 6A) F1 plants, 96.68% PMCs had two univalent telocentric chromosomes.This again demonstrated that the short arm of alien chromosome(6V) and the long arm of homoeologous wheat chromosome 6A were involved in wheat-H. villosa translocation. Due to nomally pairing of translocation chromosome in translocation line or its hybrid F_1,the resistance gene on 6VS could be regularly transmitted to the progenies.