Fusarium wilt caused by soil-borne fungus Fusarium oxysporum f. sp. vasinfectum race 4 (FOV4) is an early season disease causing root rot, and seedling wilt and death. However, it was unknown if cotton (Gossypium spp.) growth stages and root wounding affected genotypic responses to FOV4. The objectives of this study were to investigate the effects of cotton growth stage, cultivar, and root wounding on FOV4-associated disease development at 7-, 14-, 21-, and 28-d post inoculation through five replicated tests in controlled environmental conditions with temperatures at 21 to 23 °C. Seedlings inoculated at the cotyledon stage incurred the highest disease incidence (DI), disease severity rating (DSR), and mortality (MR), followed by seedlings inoculated at the 1-, 3-, and 5-true leaf stages in descending order. Root wounding at the cotyledon stage followed by immediate inoculation with FOV4 inoculum made all the tested cultivars and lines highly susceptible. Among the six cultivars tested, FM 2334GLT and Pima DP 359 RF were the most resistant, Pima S-7 was highly susceptible, and Acala 1517-08, Acala 1517–18 GLS, and Pima PHY 881 RF were susceptible. The importance of artificial inoculation at a true leaf stage with or without root wounding to identify resistance that may be undetected under field conditions was discussed.

中文翻译：

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生长阶段、品种和根伤对由枯萎病 4 号（Fusarium oxysporum f. sp. vasinfectum）引起的棉花病害发展的影响

由土传真菌Fusarium oxysporum f. 引起的枯萎病。sp。vasinfectum race 4 (FOV4) 是一种早季病害，会导致根腐病、幼苗枯萎和死亡。然而，尚不清楚棉花 ( Gossypiumspp.) 生长阶段和根部损伤影响了对 FOV4 的基因型反应。本研究的目的是通过在受控环境条件下进行五次重复试验，调查接种后 7、14、21 和 28 天棉花生长阶段、品种和根部损伤对 FOV4 相关疾病发展的影响温度为 21 至 23 °C。在子叶期接种的幼苗的发病率 (DI)、疾病严重程度 (DSR) 和死亡率 (MR) 最高，其次是在 1、3 和 5 真叶期接种的幼苗，按降序排列。在子叶阶段根部受伤，然后立即接种 FOV4 接种物，使所有测试的品种和品系都高度敏感。在测试的六个品种中，FM 2334GLT 和 Pima DP 359 RF 的抗性最强，Pima S-7 高度易感，Acala 1517-08、Acala 1517-18 GLS 和 Pima PHY 881 RF 易感。讨论了在有或没有根伤的真叶阶段人工接种以确定在田间条件下可能未检测到的抗性的重要性。