根芹优异种质资源的收集评价与筛选

［目的］筛选适宜在我国北方地区种植的根芹品种。［方法］对北京蔬菜研究中心收集的15份根芹种质资源的主要田间性状进行了比较,并对根芹的特征特性、生长特点、栽培技术等进行了简要介绍。［结果］15份根芹资源的共同特点为：茎短缩型（抽薹前）,平叶,叶扇形,叶面平滑无刺毛,叶缘有深锯齿等;7010056、7010059、7010099根芹个体较小,其他根芹品种的单根重均在200-400 g,7010197、7010061、7010096、7010100品种综合性状优良,适宜在北方地区推广种植;中早熟根芹品种的适宜定植密度为75 000-90 000株/hm^2,晚熟品种的适宜定植密度为60 000株/hm^2,缓苗后应加强水肥管理;根芹根部膨大过程中,适宜温度为白天15-20 ℃,夜间5-8 ℃。［结论］根芹品种7010197、7010061、7010096、7010100适宜在北方地区种植。     

The incidence of stolbur disease and associated yield losses in vegetable crops in South Moravia (Czech Republic)

The study was performed at a vegetable farm from 2006 to 2008 in the intensive horticultural area of Lednice (South Moravia, Czech Republic), where a stolbur (phytoplasma) epidemic had occurred. The study showed that the incidence of stolbur disease reached 15% in both tomato (Lycopersicon esculentum) and pepper (Capsicum annuum), and up to 6.7% in celeriac (Apium graveolens). There were significant yield losses in the stolbur-affected plants; total yield losses were up to 60% in tomato, 93% in pepper, and 100% in celeriac. The mean yield was significantly decreased in stolbur-affected plants, compared to healthy plants (i.e. from 42.79 to 17.21 fruits per plant in tomatoes; from 10.11 to 0.74 fruits per plant in peppers). In the locality studied, it was mainly the weed plants Convolvulus arvensis and Cirsium arvense (which were frequently interspersed among the crops), which tested positive for the stolbur phytoplasma and might have provided a reservoir for the phytoplasma infection.