The black pod disease affects cacao plantations worldwide; it is caused by the oomycete species of the genus Phytophthora. The resistance of cacao plants to the black pod is commonly evaluated by artificial inoculation of the pathogen and the monitoring of the disease symptoms. However, it is difficult to identify resistant plants because the commonly used methods for the inoculation of the pathogens produce inconsistent results. Therefore, this study aimed to develop an efficient and reliable method to evaluate the resistance of Theobroma cacao seedlings to the infection by Phytophthora palmivora. Seedlings of different cacao genotypes were inoculated with P. palmivora under greenhouse conditions using the previously reported inoculation methods and a newly proposed method, the agar–water solution method. While none of the previously reported methods was effective, the agar–water solution method ensured a 100% seedling infection under greenhouse conditions. The proposed agar–water methodology is fast, simple and reproducible. Furthermore, the evaluation of this method in susceptible (CCN-51) and tolerant (SCA-6) T. cacao genotypes produced the expected contrasting results. The agar–water solution method presented in this study is an efficient alternative inoculation protocol for the identification of cacao genotypes that are resistant to black pod under greenhouse conditions.

中文翻译：

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一种在温室条件下将棕榈疫霉（巴特勒）接种到可可幼苗中的新方法。

黑豆荚病影响全世界的可可种植园；它是由疫霉属的卵菌引起的。可可植物对黑豆荚的抗性通常通过人工接种病原体和监测病害症状来评估。然而，很难识别抗性植物，因为常用的病原体接种方法产生的结果不一致。因此，本研究旨在开发一种有效且可靠的方法来评估可可树幼苗对棕榈疫霉感染的抗性。使用先前报道的接种方法和新提出的方法，即琼脂水溶液法，在温室条件下用 P. palmivora 接种不同可可基因型的幼苗。虽然以前报道的方法都没有效果，但琼脂水溶液方法确保了温室条件下 100% 的幼苗感染。所提出的琼脂-水方法快速、简单且可重复。此外，该方法在敏感 (CCN-51) 和耐受 (SCA-6) T. cacao 基因型中的评估产生了预期的对比结果。本研究中提出的琼脂水溶液方法是一种有效的替代接种方案，用于鉴定在温室条件下对黑豆荚有抗性的可可基因型。可可基因型产生了预期的对比结果。本研究中提出的琼脂水溶液方法是一种有效的替代接种方案，用于鉴定在温室条件下对黑豆荚有抗性的可可基因型。可可基因型产生了预期的对比结果。本研究中提出的琼脂水溶液方法是一种有效的替代接种方案，用于鉴定在温室条件下对黑豆荚有抗性的可可基因型。