South American Leaf Blight (SALB) is the primary limitation to the establishment of new rubber (Hevea brasiliensis) crops in Latin America. This study aimed to assess the temporal dynamics of resistance to SALB in 99 elite Colombian genotypes and the IAN 873 cultivar (control) of H. brasiliensis in small-scale clone trials conducted under conditions with a high disease prevalence in the northwestern Colombian Amazon. Resistance monitoring was carried out on a monthly basis and analyzed over five climatic periods. Three variables were recorded: attack severity (AT, ranging from 0 to 4), reaction type (TR, ranging from 1 to 6) and stromal density (ST, ranging from 0 to 4). The maximum scores for TR and ST were used to classify the level of resistance of the genotypes. Highly significant differences in the mean values of AT, TR and ST among the genotypes, across the periods, and in the interaction between genotype and period were found. Over time, an increase in symptoms (AT) and signs (TR and ST) of SALB was observed. During the rainy periods, SALB intensity was highest, resulting in a leaf area affected ranging from 16 to 30%. Eight genotypes showed partial resistance (PR) (TR < 5 and ST < 2), while 16 genotypes demonstrated complete resistance (CR) (TR < 3 and ST = 0), and 76 genotypes were highly susceptible (HS) (TR > 5 or ST > 2). The temporal analysis identified 23 Colombian superior genotypes with varying degrees of SALB resistance, which can be a valuable breeding resource for improving SALB management in the Colombian Amazon region.

南美叶枯病 (SALB) 是拉丁美洲种植新橡胶 ( Hevea brasiliensis ) 作物的主要限制。本研究旨在评估 99 个哥伦比亚精英基因型和H. brasiliensis IAN 873 品种（对照）对 SALB 抗性的时间动态，这是在哥伦比亚西北部亚马逊地区疾病高发条件下进行的小规模克隆试验。每月进行一次抗性监测并分析五个气候周期。记录了三个变量：发作严重程度（AT，范围从 0 到 4）、反应类型（TR，范围从 1 到 6）和基质密度（ST，范围从 0 到 4）。TR 和 ST 的最大分数用于对基因型的抗性水平进行分类。发现不同基因型、不同时期以及基因型与时期之间的相互作用的 AT、TR 和 ST 平均值存在高度显着差异。随着时间的推移，观察到 SALB 的症状（AT）和体征（TR 和 ST）有所增加。雨季期间，SALB强度最高，导致叶面积受影响16%至30%。8 个基因型显示部分耐药 (PR)（TR < 5 和 ST < 2），16 个基因型显示完全耐药（CR）（TR < 3 和 ST = 0），76 个基因型高度敏感（HS）（TR > 5）或 ST > 2)。时间分析确定了 23 个具有不同程度 SALB 抗性的哥伦比亚优良基因型，这可以成为改善哥伦比亚亚马逊地区 SALB 管理的宝贵育种资源。