Faculty of Science and Technology, Dhonburi Rajabhat University, Bangkok 10600, Thailand.
J Genet. 2020;99.
Fourteen cucumber lines were tested for genetic homozygosity and performed pairwise comparison to identify a pair with the highest DNA polymorphic level. Cucumber accessions CSL0067 and CSL0139 were selected to generate 315 F populations. The genetic linkage map based on 66 polymorphic SSR markers was constructed. It composed of eight linkage groups (LGs) spanning 474.4 cM. Downy mildew disease reaction was evaluated in cotyledons, first and second true leaf on 7, 10, and 14 day after inoculation. The results showed that downy mildew resistance was controlled by multiple recessive genes. The susceptible to resistant ratio of F progenies fit 9:7 susceptible/resistant segregation types corresponding to duplicate recessive epistasis. Fourteen QTLs were detected. The phenotypic variance ranged from 5.0 to 12.5%, while LOD values ranged from 3.538 to 9.165. Two major QTLs and two QTL hotspots were identified. Moreover, the additive effects data explained that these QTL reduced downy mildew susceptibility.
对 14 个黄瓜品系进行遗传同质性测试，并进行成对比较，以确定一对具有最高 DNA 多态性水平的品系。选择黄瓜品系 CSL0067 和 CSL0139 产生 315 个 F1 群体。基于 66 个多态性 SSR 标记构建了遗传连锁图谱。它由 8 个连锁群（LG）组成，跨度为 474.4cM。在接种后 7、10 和 14 天，在子叶、第一真叶和第二真叶上评估了霜霉病的反应。结果表明，霜霉病抗性由多个隐性基因控制。F1 后代的感病/抗病比值符合 9:7 的感病/抗病分离类型，对应于双隐性上位性。检测到 14 个 QTL。表型方差范围为 5.0%至 12.5%，而 LOD 值范围为 3.538 至 9.165。鉴定出两个主要 QTL 和两个 QTL 热点。此外，加性效应数据表明这些 QTL 降低了霜霉病的易感性。
