U.S. Department of Agriculture, Agricultural Research Service, Crop Improvement and Protection Research Unit, Salinas, CA 93905.
Horticultural Sciences Department, Everglades Research and Education Center, University of Florida, Belle Glade, FL 33430.
Plant Dis. 2022 Oct;106(10):2583-2590. doi: 10.1094/PDIS-09-21-2087-RE. Epub 2022 Sep 9.
Spring mix is a popular packaged salad that contains lettuce ( L.) as one of its main ingredients. Plants for baby leaf lettuce (BLL) production are grown at very high densities, which enhances the occurrence of bacterial leaf spot (BLS) caused by pv. (), a disease that can make the crop unmarketable. The market demands disease-free, high-quality BLL all year round. Growing highly BLS-resistant cultivars will reduce loss of yield and quality, thus minimizing economic detriment to lettuce and spring mix growers. The research objectives were to identify lettuce accessions resistant to BLS and associated quantitative trait loci (QTL). A total of 495 lettuce accessions were screened with six isolates (BS0347, BS2861, BS3127, L7, L44, and Sc8B) of . Accessions showing overall high-level resistance to all tested isolates were 'Bunte Forellen', PI 226514, 'La Brillante', ARM09-161-10-1-4, 'Grenadier', 'Bella', PI 491210, 'Delight', and 'Romana Verde del Mercado'. Genome-wide association studies of BLS resistance by mixed linear model analyses identified significant QTLs on four lettuce chromosomes (2, 4, 6, and 8). The most significant QTL was on Chromosome 8 ( = 1.42 × 10), which explained 6.7% of total phenotypic variation for the disease severity. Accessions with a high level of resistance detected in this study are valuable resources for lettuce germplasm improvement. Molecular markers closely linked to QTLs can be considered for marker-assisted selection to develop new BLL lettuce cultivars with resistance to multiple races of .
田园沙拉是一种受欢迎的包装沙拉，其中生菜（L.）是其主要成分之一。生产婴儿生菜（BLL）的植物种植密度非常高，这增加了由 pv. 引起的细菌性叶斑病（BLS）的发生，（），一种会使作物失去市场价值的疾病。市场全年都需要无病、高质量的 BLL。种植高抗 BLS 的品种将减少产量和质量的损失，从而最大限度地减少生菜和田园沙拉种植者的经济损失。研究目的是鉴定抗 BLS 的生菜品种和相关的数量性状位点（QTL）。总共筛选了 495 个生菜品种，用 6 个分离株（BS0347、BS2861、BS3127、L7、L44 和 Sc8B）进行了筛选。对所有测试分离株均表现出高水平抗性的品种有“Bunte Forellen”、PI 226514、“La Brillante”、ARM09-161-10-1-4、“Grenadier”、“Bella”、PI 491210、“Delight”和“Romana Verde del Mercado”。通过混合线性模型分析对 BLS 抗性的全基因组关联研究，在生菜的 4 条染色体（2、4、6 和 8）上鉴定到显著的 QTL。最显著的 QTL 位于第 8 号染色体（= 1.42×10），解释了疾病严重程度总表型变异的 6.7%。本研究中检测到的具有高水平抗性的品种是生菜种质改良的有价值资源。与 QTL 紧密连锁的分子标记可用于标记辅助选择，以开发具有抗多种 pv. 分离株的新 BLL 生菜品种。
