Table_2_Marker-assisted introgression of wild chromosome segments conferring resistance to fungal foliar diseases into peanut (Arachis hypogaea L.).xlsx

IntroductionFungal foliar diseases can severely affect the productivity of the peanut crop worldwide. Late leaf spot is the most frequent disease and a major problem of the crop in Brazil and many other tropical countries. Only partial resistance to fungal diseases has been found in cultivated peanut, but high resistances have been described on the secondary gene pool.MethodsTo overcome the known compatibility barriers for the use of wild species in peanut breeding programs, we used an induced allotetraploid (Arachis stenosperma × A. magna)4x, as a donor parent, in a successive backcrossing scheme with the high-yielding Brazilian cultivar IAC OL 4. We used microsatellite markers associated with late leaf spot and rust resistance for foreground selection and high-throughput SNP genotyping for background selection.ResultsWith these tools, we developed agronomically adapted lines with high cultivated genome recovery, high-yield potential, and wild chromosome segments from both A. stenosperma and A. magna conferring high resistance to late leaf spot and rust. These segments include the four previously identified as having QTLs (quantitative trait loci) for resistance to both diseases, which could be confirmed here, and at least four additional QTLs identified by using mapping populations on four generations.DiscussionThe introgression germplasm developed here will extend the useful genetic diversity of the primary gene pool by providing novel wild resistance genes against these two destructive peanut diseases.

引言：真菌性叶部病害对全球花生作物的产量产生严重影响。晚疫病是最常见的病害，也是巴西及众多热带国家作物的主要问题。在栽培花生中仅发现对真菌病害的部分抗性，但已在次级基因库中描述了高度抗性。方法：为了克服在花生育种计划中使用野生种所面临的已知兼容性障碍，我们采用诱导的四倍体杂种（Arachis stenosperma × A. magna）作为供体亲本，与高产巴西栽培品种IAC OL 4进行连续回交。我们利用与晚疫病和锈病抗性相关的微卫星标记进行前景选择，并采用高通量SNP基因分型进行背景选择。结果：通过这些工具，我们培育出具有高栽培基因组恢复率、高产潜力和来自A. stenosperma和A. magna的野生染色体片段的农艺适应型系，这些片段包括四个之前已识别出对这两种病害抗性QTL（数量性状位点）的片段，并且在此得到了验证，以及至少通过在四代群体中进行图谱构建确定的四个额外的QTL。讨论：本研究所开发的转育种质将通过对这两种破坏性花生病害提供新的野生抗性基因，从而扩展初级基因库的有用遗传多样性。