Genotypes of conilon coffee and their reaction to coffee leaf rust

ABSTRACT The objective of this study was to evaluate the behavior of 54 conilon coffee clones from the Incaper Genetic Improvement Program to rust under controlled conditions of temperature and photoperiod. A completely randomized design with three replicates was used, and each replicate was composed of 16 leaf disks each, which were packed in gerboxes and inoculated with 104 spores.mL-1 H. vastatrix. The gerboxes were stored in the absence of light at 22ºC for 48 hours and subsequently at 12-hour photoperiod until the end of the experiment. The evaluated resistance components were: incubation period, latent period, incidence, percentage of disks with sporulation, number of spores and severity. Based on the results, three groups of conilon coffee genotypes were identified: Resistant, Moderately Resistant and Susceptible. To the Resistant group, 19 genotypes were allocated; to the Moderately Resistant group, 19 genotypes were allocated and to the Susceptible group 16 susceptible genotypes were allocated. Thus, results led to the conclusion that there is a variation in the resistance level of C. canephora genotypes to H. vastatrix. Such information subsidizes breeding programs in properly selecting C. canephora progenies for resistance to rust.

摘要
本研究旨在可控温度与光周期条件下，评估来自Incaper遗传改良计划的54份科尼隆咖啡（conilon coffee）无性系对咖啡锈病的抗性表现。本试验采用完全随机设计，设置3次生物学重复，每重复包含16个叶盘，将叶盘置于培养盒（gerbox）中，以浓度为10^4孢子·毫升^-1的咖啡驼孢锈菌（H. vastatrix）菌液进行接种。将培养盒置于无光环境中，于22℃条件下培养48小时，随后转移至12小时光周期的培养环境中，直至试验结束。本试验评估的抗性指标包括：潜育期、潜伏期、发病率、产孢叶盘占比、孢子产量及病情严重度。基于试验结果，可将供试科尼隆咖啡基因型划分为3类：抗病型、中抗型及感病型。其中抗病型组包含19份基因型，中抗型组包含19份基因型，感病型组则包含16份感病基因型。综上，本研究结果表明，刚果咖啡（C. canephora）不同基因型对咖啡驼孢锈菌的抗性水平存在显著差异。该研究结果可为咖啡育种项目中精准筛选抗锈病刚果咖啡后代提供理论支撑。