Downy mildew caused by Pseudoperonospora cubensis is one of the major production constraints of ridge gourd cultivation causing severe yield loss. Host resistance is the most effective and sustainable means of controlling this disease. Ten varieties and thirteen advanced breeding lines of ridge gourd were screened under natural epiphytotics for two seasons and ten moderately resistant lines were identified based on per cent disease index (PDI). Among them, two lines IIHR-DMR-18-4-4 and IIHR-DMR-18-65-1 clearly showed lower disease severity with PDI of 23.46 and 24.03, respectively, while highly susceptible lines showed higher disease severity with 73 PDI. The area under disease progress curve (AUDPC) values of the moderately resistant lines IIHR-DMR-18-4-4 and IIHR-DMR-18-65-1 (1171.86 and 1190.86) were one third of those of the highly susceptible lines (3648.35). Similarly apparent infection rate (r) per week was lower in the moderately resistant lines (0.88) than in the susceptible lines (1.23), indicating slow disease progression (slow mildew) in these moderately resistant lines. Moderate resistance reaction was confirmed by the production of fewer sporangia/cm² (1.08 × 10⁴/cm²) and lower percentage of infected leaf area (8.6%, 8.4%) which was almost ten times less than that observed in highly susceptible lines such as Pusa Nasdar and Jaipur Long with high sporangia production (1.48 × 10⁵/cm²,1.14 × 10⁵/cm²) and leaf area damage (67.8%, 76.9%) respectively. The identified moderately resistant lines IIHR-DMR-18-4-4 and IIHR-DMR-18-65-1 showed slow mildew development and can be utilized in the breeding program to develop resistant cultivars of ridge gourd with desirable horticultural traits.

由古巴假霜霉引起的霜霉病是葫芦种植的主要生产限制因素之一，造成严重的减产。宿主抗性是控制这种疾病最有效和可持续的手段。在自然附生条件下，经过两季筛选，筛选出10个葫芦品种、13个先进育种系，并根据百分病指数（PDI）鉴定出10个中抗性品系。其中，IIHR-DMR-18-4-4和IIHR-DMR-18-65-1两个品系明显表现出较低的疾病严重程度，PDI分别为23.46和24.03，而高感品系则表现出较高的疾病严重程度，PDI为73。中度抗性品系 IIHR-DMR-18-4-4 和 IIHR-DMR-18-65-1 的疾病进展曲线下面积 (AUDPC) 值（1171.86 和 1190.86）是高感品系的三分之一（ 3648.35）。同样，中度抗性品系的每周表观感染率 (r) (0.88) 低于易感品系 (1.23)，表明这些中度抗性品系的疾病进展缓慢（慢霉）。通过产生较少的孢子囊/cm ² (1.08 × 10 ⁴ /cm ² )和较低的受感染叶面积百分比(8.6%、8.4%)证实了中度抗性反应，这几乎比在高感品系中观察到的低十倍例如 Pusa Nasdar 和 Jaipur Long 的孢子囊产量（1.48 × 10 ⁵ /cm ²、1.14 × 10 ⁵ /cm ²）和叶面积损害（67.8%、76.9%）分别较高。鉴定出的中度抗性品系IIHR-DMR-18-4-4和IIHR-DMR-18-65-1显示出霉菌发育缓慢，可用于育种计划中开发具有理想园艺性状的抗性葫芦品种。