Harveson R M, Rush C M
University of Nebraska, Panhandle Research and Extension Center, 4502 Ave. I, Scottsbluff 69361.
Texas Agricultural Experiment Station, P.O. Drawer 10, Bushland 79012.
Plant Dis. 2002 Aug;86(8):901-908. doi: 10.1094/PDIS.2002.86.8.901.
The effects of cultivar mixtures and two irrigation frequency treatments were evaluated over two seasons for their impact on a complex of sugar beet root diseases in three fields infested with the fungal pathogens Aphanomyces cochliodes, Fusarium oxysporum f. sp. radicis-betae, Rhizoctonia solani, and the viral pathogen Beet necrotic yellow vein virus (BNYVV). Irrigations after emergence consisted of two or five (two 1994 studies) and three or six (1995 study) applications of water for dry and wet treatments, respectively. Cultivar treatments included MH9155, HH67, Ranger, Rhizosen, and four combinations of these same cultivars. Disease progress was monitored through destructive sampling of plants exhibiting foliar symptoms typical of root disease during the season. At harvest, data on root and sucrose yields, sucrose percentage, and a root disease index were collected. No significant irrigation × cultivar treatment interactions were observed. Few significant differences were observed between irrigation treatments involving measured yield components. Reduced irrigations however, resulted in significantly lower disease incidence in all three repeated experiments when cultivar treatments were combined. No added benefits were observed for increasing yield or decreasing root disease by planting mixed cultivars, compared to the same cultivars planted individually. Several regionally adapted cultivars performed as well or better than mixtures under the unusually high levels of disease pressure in test fields. When few alternative options are available, sugar beet growers may still benefit from reducing irrigations, and growing locally adapted cultivars in soils severely infested with root pathogens.
在三个受到真菌病原体腐皮镰孢菌、尖孢镰刀菌甜菜专化型、立枯丝核菌以及病毒病原体甜菜坏死黄脉病毒（BNYVV）侵染的田块中，对品种混合物和两种灌溉频率处理在两个季节里对甜菜根病复合体的影响进行了评估。出苗后的灌溉，在干旱和湿润处理中，分别为两次或五次（两项1994年的研究）以及三次或六次（1995年的研究）浇水。品种处理包括MH9155、HH67、Ranger、Rhizosen以及这些相同品种的四种组合。通过在生长季对表现出典型根病叶部症状的植株进行破坏性采样来监测病害进展。收获时，收集了根产量、蔗糖产量、蔗糖百分比以及根病指数的数据。未观察到显著的灌溉×品种处理交互作用。在涉及实测产量构成因素的灌溉处理之间，未观察到显著差异。然而，当将品种处理合并时，在所有三个重复试验中，减少灌溉导致病害发生率显著降低。与单独种植相同品种相比，种植混合品种在提高产量或降低根病方面未观察到额外益处。在试验田异常高的病害压力下，几个适应当地的品种表现与混合物一样好或更好。当几乎没有其他选择时，甜菜种植者通过减少灌溉以及在严重受根病原体侵染的土壤中种植适应当地的品种仍可能受益。
