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BACKGROUND

Psathyrostachys huashanica Keng (2n = 2x = 14, NsNs) carries many outstanding agronomic traits, therefore is a valuable resource for wheat genetic improvement. Wheat-P. huashanica translocation lines are important intermediate materials for wheat breeding and studying the functions of alien chromosomes. However, powdery mildew resistance in these translocation lines has not been reported previously.

RESULTS

This study developed a novel wheat-P. huashanica translocation line TR77 by selecting a F progeny from the cross between heptaploid hybrid H8911 (2n = 7x = 49, AABBDDNs) and durum wheat line Trs-372. Chromosome karyotype of 2n = 42 = 21II was observed in both mitotic and meiotic stages of TR77. Genomic in situ hybridization analysis identified two translocated chromosomes that paired normally at meiosis stage in TR77. Molecular marker analysis showed that part of chromosome 5D was replaced by part of alien chromosome fragment 5Ns. It meant replacement made part 5DL and part 5NsL·5NsS existed in wheat background, and then translocation happened between these chromosomes and wheat 3D chromosome. Fluorescence in situ hybridization demonstrated that TR77 carries dual translocations: T3DS-5NsL·5NsS and T5DL-3DS·3DL. Analysis using a 15 K-wheat-SNP chip confirmed that SNP genotypes on the 5D chromosome of TR77 matched well with these of P. huashanica, but poorly with common wheat line 7182. The translocation was physically located between 202.3 and 213.1 Mb in 5D. TR77 showed longer spikes, more kernels per spike, and much better powdery mildew resistance than its wheat parents: common wheat line 7182 and durum wheat line Trs-372.

CONCLUSIONS

TR77 is a novel stable wheat-P. huashanica T3DS-5NsL·5NsS and T5DL-3DS·3DL dual translocation line and showed significant improved spike traits and resistance to powdery mildew compared to its parents, thus, it can be an useful germplasm for breeding disease resistance and studying the genetic mechanism of dual translocations.

BACKGROUND

RESULTS

CONCLUSIONS

背景

华山新麦草（2n = 2x = 14，NsNs）具有许多优良的农艺性状，因此是小麦遗传改良的宝贵资源。小麦-华山新麦草易位系是小麦育种和研究外源染色体功能的重要中间材料。然而，这些易位系的抗白粉病特性以前尚未报道过。

结果

本研究通过从七倍体杂种 H8911（2n = 7x = 49，AABBDDNs）与硬粒小麦系 Trs-372 的杂交后代中选择 F 代，获得了一个新的小麦-华山新麦草易位系 TR77。在 TR77 的有丝分裂和减数分裂阶段都观察到 2n = 42 = 21II 的染色体核型。基因组原位杂交分析鉴定出 TR77 中有两条易位染色体在减数分裂阶段正常配对。分子标记分析表明，部分 5D 染色体被外源染色体片段 5Ns 取代。这意味着部分 5DL 和部分 5NsL·5NsS 存在于小麦背景中，然后这些染色体与小麦 3D 染色体之间发生了易位。荧光原位杂交表明，TR77 携带双重易位：T3DS-5NsL·5NsS 和 T5DL-3DS·3DL。使用 15K 小麦-SNP 芯片进行的分析证实，TR77 的 5D 染色体上的 SNP 基因型与华山新麦草的 SNP 基因型匹配良好，但与普通小麦 7182 匹配较差。该易位位于 5D 染色体上的 202.3 到 213.1 Mb 之间。TR77 比其小麦亲本：普通小麦 7182 和硬粒小麦系 Trs-372 具有更长的穗、更多的穗粒数和更好的抗白粉病能力。