Apple blue mold causes significant postharvest economic losses worldwide. A blue mold resistance locus, qM-Pe3.1, was previously identified on chromosome 3 of Malus sieversii PI 613981, a wild accession with inferior fruit quality. Introgression of the resistance allele into elite breeding germplasm is difficult and success of introgression and the effect of the PI 613981 genome on fruit quality cannot be phenotypically evaluated until fruiting, which occurs approximately 5 years from seed. In this study, introgression of the qM-Pe3.1 resistance allele was achieved by rapid cycle breeding, utilizing the transgenic line T1190 constitutively expressing the BpMADS4 early-flowering gene. This was supported by DNA-based diagnostic information that enabled marker-assisted selection for blue mold resistance using a locus-specific DNA test developed to detect the qM-Pe3.1 resistance allele in offspring (foreground selection). Of 75 second-generation ([‘Gala’ × PI 613981] × T1190) offspring carrying BpMADS4, 43 also carried the qM-Pe3.1 resistance allele. DNA tests for other trait loci were used to identify other desirable alleles related to fruit quality in progeny and 6874 genome-wide SNP markers (from an apple 20K Illumina® SNP array) were used to identify undesirable genomic segments of PI 613981 (background selection). Three individuals identified with favorable recombination close to qM-Pe3.1 and less than 25% of M. sieversii unimproved genome were selected as best suited for the elimination of unimproved DNA segments in subsequent generations. Our pipeline for introgression of qM-Pe3.1, facilitated by marker-assisted foreground and background selection, successfully advanced this promising germplasm in readiness for the next generation.

苹果蓝霉病在全球范围内造成了严重的收获后经济损失。先前在苹果属苹果（Malus sieversii） PI 613981的3号染色体上鉴定出蓝色霉菌抗性位点qM- Pe 3.1，这是一种劣质水果的野生种。难以将抗性等位基因渗入优良育种种质中，直到从结实开始（从种子开始约5年），才能从表型上评估渗入成功和PI 613981基因组对果实品质的影响。在这项研究中，利用组成型表达BpMADS4的转基因品系T1190，通过快速周期育种实现了qM- Pe 3.1耐药等位基因的渐渗早开花基因。这由基于DNA的诊断信息提供支持，该诊断信息可使用位点特异性DNA测试开发标记物辅助选择蓝霉菌抗性，以检测后代的qM- Pe 3.1耐药等位基因（前景选择）。在携带BpMADS4的75个第二代（['Gala'×PI 613981]×T1190）后代中，有43个还携带了qM- Pe 3.1抗性等位基因。使用其他性状基因座的DNA测试来鉴定与子代果实品质相关的其他理想等位基因，并使用6874个全基因组SNP标记（来自苹果公司的20KIllumina®SNP阵列）鉴定PI 613981的不良基因组片段（背景选择） 。确定了与qM- Pe接近的良好重组的3个人选择3.1和少于25％的sieversii未改良基因组作为最适合消除后代中未改良DNA片段的基因。通过标记物辅助的前景和背景选择，我们的qM- Pe 3.1渗入管道成功地使这种有前途的种质为下一代做好了准备。