Bacterial fruit blotch (BFB) caused by Acidovorax citrulli is a serious threat to the watermelon industry. Currently, there are no commercial watermelon cultivars with resistance to BFB. In this 3‐yr study, we conducted a screening of 1,452 Citrullus spp. cultigens (PIs and cultivars) for resistance to BFB at the immature fruit stage. However, due to high levels of missing data, many cultigens require additional testing to confirm resistance. Fruit BFB symptoms presented initially as raised bumps, then progressed to blotching, cracking, and internal necrosis. Resistant cultigens rarely proceeded beyond raised bumps at the infection site. Fruit resistance is significantly affected by environmental conditions and has low heritability. Among a subset of cultigens selected for high resistance and susceptibility during the first 2 yr of screening and retested using increased replications, PI 494819 [C. lanatus (Thunb.) Matsum. & Nakai., Zambia], PI 596659 (C. amarus Schrad., South Africa), PI 596670 (C. amarus, South Africa), PI 490384 [C. mucosospermus (Fursa) Fursa, Mali], and PI 596656 (C. amarus, South Africa) had average disease ratings of <1; significantly more resistance than the commercial check, Charleston Gray; low plant‐to‐plant variability within each PI; and infrequent incidence of advanced symptoms. These PIs are potential sources of fruit resistance for breeding programs as well as for research focused on understanding the underlying mechanisms and genetics.

中文翻译：

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西瓜果实耐细菌性斑点病的筛选

Acidovorax citrulli引起的细菌性水果斑点（BFB）对西瓜产业构成严重威胁。目前，尚无对BFB有抗性的商业西瓜品种。在这项为期3年的研究中，我们对1,452株柑橘进行了筛选spp。品种（PI和品种）在未成熟果实阶段对BFB的抗性。但是，由于缺少大量数据，许多栽培者需要进行额外的测试以确认抗药性。水果BFB症状最初表现为凸起的肿块，然后发展为斑点，破裂和内部坏死。抗性栽培种很少在感染部位超出凸起的地方进行。耐果性受环境条件的影响很大，遗传力较低。PI 494819 [ C. lanatus（Thunb。）Matsum。＆中井。，尚比亚]，PI 596659（C.苦竹SCHRAD。，南非），PI 596670（C.苦竹，南非），PI 490384 （马里的粘膜隐孢子虫（C. mucosospermus（Fursa）Fursa）和南非的PI 596656（隐孢子虫C. amarus））的平均疾病等级小于1；比商业支票查尔斯顿·格雷更具抵抗力；每个PI内植物之间的变异性低; 晚期症状的发生率不高。这些PI可能是育种计划以及旨在了解潜在机制和遗传学的研究的果实抗性的潜在来源。