Table_1_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.

真菌性叶部病害对全球花生产量的影响极大。晚疫病是最常见的病害，也是巴西及其他许多热带国家花生种植的主要问题。在栽培花生中仅发现对真菌病害的局部抗性，但已在次级基因库中描述了高度抗性。方法为克服在花生育种计划中应用野生种所存在的已知兼容性障碍，本研究采用诱导的四倍体杂种（Arachis stenosperma × A. magna）4x作为供体亲本，与高产巴西栽培品种IAC OL 4进行连续回交。采用与晚疫病和锈病抗性相关的微卫星标记进行前景选择，并利用高通量SNP基因分型进行背景选择。结果利用这些工具，我们培育出农业适应性强的品种，具有高栽培基因组恢复率、高产潜力，并含有来自A. stenosperma和A. magna的野生染色体片段，这些片段能够提供对晚疫病和锈病的高度抗性。这些片段包括之前已确定的四个具有对这两种疾病抗性QTL（数量性状位点）的片段，此处得以确认，以及至少四个通过在四代映射群体中使用的额外QTLs。讨论在本研究中开发的引入种质将通过对这两种破坏性花生病害提供新颖的野生抗性基因，扩展初级基因库的有用遗传多样性。