Cotton (Gossypium spp.) is an economically important crop which provides a significant source of fiber, animal feed, and food oil worldwide. Bacterial blight (BB), caused by Xanthomonas citri pv. malvacearum (Xcm), infects the aerial part of the cotton plant at all stages and can cause a significant loss in yield and fiber quality. In this study, 288 Upland (G. hirsutum) and 8 Pima (G. barbadense) commercial transgenic cultivars and elite breeding lines were divided into 10 replicated tests and evaluated for BB resistance using the toothpick scratching method in the greenhouse in 2016–2017. Five Upland and four Pima genotypes were used as resistant and susceptible controls, respectively. The percentage of susceptible plants with water-soaking symptoms was calculated on a replication basis for each genotype. While all the commercial Pima cultivars tested were susceptible, 21 commercial Upland cultivars were resistant to Xcm race 18. A total of 22 elite public breeding lines were resistant, including 11 lines from the University of Arkansas with an active breeding program for BB resistance and 1–4 resistant lines from five other public breeding programs without an active screening component for BB resistance. Of more than 150 breeding lines developed at New Mexico State University, 11 were found to be resistant to BB. Many commercial cultivars and public breeding lines were found to contain various levels of susceptible plants and are therefore heterogeneous in BB resistance. The results suggest that the resistance to Xcm race 18 can be easily bred in breeding without a selection pressure. A pedigree analysis showed that there are likely different sources of BB resistance. The resistant cultivars and lines identified should be a valuable resource to improve BB resistance in cotton breeding.

棉花（棉属）是一种重要的经济作物，在全世界范围内提供大量的纤维，动物饲料和食用油。细菌性疫病（BB），由Xanthomonas citri pv引起。malvacearum（Xcm）会在各个阶段感​​染棉花植物的空中部分，并可能导致产量和纤维质量的重大损失。在这项研究中，有288个陆地棉（G. hirsutum）和8个比马（G. barbadense））将商业转基因品种和优良育种系分为10个重复试验，并在2016-2017年间使用牙签刮擦法评估了BB的抗性。五种高地和四种皮马基因型分别用作抗药性和易感对照。对于每种基因型，以复制为基础计算出具有水浸症状的易感植物的百分比。虽然所有测试的Pima商业品种均易感，但21个陆地棉商业品种对Xcm种族18具有抗性。共有22个优良的公共育种品系具有抗性，其中包括来自阿肯色大学的11个具有BB抗性积极育种计划的品系。来自其他五个公共育种计划的–4个抗性品系，但没有针对BB抗性的有效筛选成分。在新墨西哥州立大学开发的150多个育种系中，有11个对BB具有抗性。发现许多商业品种和公共育种品系包含各种水平的易感植物，因此在BB抗性方面异质。结果表明，在没有选择压力的情况下可以容易地育种对Xcm族18的抗性。家谱分析表明，可能有不同的BB抵抗源。确定的抗性品种和品系应该是提高棉花育种对BB的抗性的宝贵资源。结果表明，在没有选择压力的情况下可以容易地育种对Xcm族18的抗性。家谱分析表明，可能有不同的BB抵抗源。确定的抗性品种和品系应该是提高棉花育种对BB的抗性的宝贵资源。结果表明，在没有选择压力的情况下可以容易地育种对Xcm族18的抗性。家谱分析表明，可能有不同的BB抵抗源。确定的抗性品种和品系应该是提高棉花育种对BB的抗性的宝贵资源。