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121.
122.
[目的]明确降雨量变化对烟草生长及病害发生的影响。[方法]于2010~2014年调查昌宁烟区烟草病害,并研究降雨量变化对烟草生长及病害发生的影响。[结果]昌宁烟草主产区共发生病害13种,其中,主要病害有烟草黑胫病、烟草青枯病、烟草根黑腐病、烟草白粉病和烟草赤星病;各年份间随着降雨量不同,烟草病害发生程度亦有所变化,旺长期降雨量偏少时部分病害发病较轻,烟草黑胫病和烟草青枯病病情指数均达20,发病烟株多被2种或2种以上主要病害侵染。2012年烟草根结线虫病被首次发现,应引起重视。[结论]试验结果为昌宁烟区烤烟的种植、病害预防及防治提供了参考。 相似文献
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124.
基于多重RT-PCR技术检测新疆甜瓜主栽区3种病毒病及其分布 总被引:5,自引:0,他引:5
采用同源克隆的方法,从新疆感染病毒病的甜瓜中克隆获得WMV、CMV、ZYMV 3种病毒CP蛋白基因的部分片段。并基于单重RT-PCR扩增条件,采用单因素分析法,优化所获得多重RT-PCR的反应体系,利用多重PT-PCR体系对48份供试样品检测。结果表明,多重RT-PCR的检测结果与单重RT-PCR结果一致,说明构建的多重RT-PCR体系具有一定准确性和稳定性,可以用于WMV、CMV、ZYMV 3种病毒的快速检测、病源鉴定、阳性筛选等研究。通过分析甜瓜主要种植区病毒病的多重RT-PCR检测结果,初步得出新疆甜瓜主栽区3种病毒的分布现状与侵染形式,从而为病毒病的防治工作提供依据,以期对新疆瓜果生产中病毒防治,田间检测,流行病学调查以及抗病毒病甜瓜育种等研究提供相应的理论基础与依据。 相似文献
125.
牛病毒性腹泻病活疫苗BVDV2/JZ05-1株毒力返强试验 总被引:1,自引:0,他引:1
研究了BVDV2/JZ05-1株免疫犊牛后是否会出现毒力返强现象.以病毒含量为10-7.26 TCID50/mL的BVDV2/JZ05-1活疫苗滴鼻免疫犊牛(4mL/头),通过疫苗回滴,连续临床观察,采集抗凝血和鼻拭子,对淋巴细胞数量变化进行分析,并从淋巴细胞和鼻拭子中分离病毒.结果表明,BVDV活疫苗BVDV2/JZ05-1株免疫犊牛没有出现BVDV感染的临床症状,淋巴细胞数量正常,鼻拭子和淋巴细胞病毒分离阴性.可见,该毒株对犊牛免疫没有出现毒力返强的现象. 相似文献
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127.
《Communications in Soil Science and Plant Analysis》2012,43(2):229-243
Abstract Phytophthora root rot (PRR) is an important disease of alfalfa (Medicago sativa L.) in wet soils. Excess soil water (ESW) stress is required for the successful infection and development of PRR. The effects of P at 0, 40, and 80 μg.g‐1 soil and K at 0, 120, and 240 μg.g‐1 soil (in factorial combinations) on the severity of PRR or ESW stress was investigated on a PRR‐susceptible (Iroquois) and a resistant (Oneida) alfalfa cultivar in a greenhouse trial. P and K applications significantly increased the dry weight of tops prior to imposition of PRR or ESW stress. However, plants subjected to PRR or ESW stress did not respond significantly to P or K and there was no significant effect of P or K on the severity of PRR or ESW injury. The plants subjected to PRR or ESW stress had lower tissue P concentration than those under stress‐free conditions. Increasing P additions resulted in a significant increase in P concentration of Iroquois plants, while in Oneida the response was non‐significant. The response of K concentration in the plant to increasing K additions was dependant on P levels. 相似文献
128.
《Scandinavian Journal of Forest Research》2012,27(2):147-154
During the 1990s, there were serious outbreaks of the pathogen Lophodermium seditiosum on pine seedlings in Swedish forest nurseries, even though the seedlings had been treated with the fungicide propiconazole. The present experiment was carried out to evaluate two other fungicides, fluazinam and azoxystrobin, as possible alternatives to propiconazole. In the tests, which were all carried out in the same forest nursery, seedlings were treated with either propiconazole, fluazinam or azoxystrobin, and the proportion of needles with ascocarps of L. seditiosum and the number of ascocarps per needle were recorded over the following 2 yrs. Seedlings treated with azoxystrobin already appeared healthier than control seedlings in September of the first year, and by November all azoxystrobin-treated seedlings had fewer ascocarps per needle compared with control seedlings. In autumn of the second year, there were no ascocarps on seedlings treated with fluazinam or azoxystrobin, whereas seedlings treated with propiconazole had similar numbers of ascocarps to non-treated control seedlings. 相似文献
129.
Among the recommended measures for citrus Huanglongbing (HLB) management, the systematic elimination of symptomatic trees is the most argued and difficult to be accepted and accomplished by citrus growers. Elimination of recently affected HLB trees represents a short term yield loss and cost increase due to the need of frequent inspections and removal operations. This work aimed to evaluate the effect of different frequencies of inoculum reduction applied at individual citrus blocks scale (or local inoculum reduction) on HLB temporal progress. Eight experiments were carried out in new planted and older citrus blocks with 504–1290 trees/plot. In all experiments, inspections to detect symptomatic trees were done in a fortnightly or monthly frequency. The treatments of frequencies of local inoculum reduction varied from fortnightly to 6 months. Annual disease progress rate was estimated by logistic model for each plot. No difference on HLB progress rates among treatments was observed, except in experiments 1 and 3 where less frequent tree removal resulted in higher disease progress rate. This ineffectiveness of local inoculum reduction on the disease progress rate was explained by the higher weight of primary spread on HLB epidemics than the secondary spread within plots associated with small size and narrow shape of treated plots (except for experiments 1 and 3), high dispersal capacity of HLB-insect vector among plots and groves, and strong control of psyllid within the plots (except for experiment 1, with poor insecticide spray program). Also, the high amount of inspections to detect symptomatic trees before the eradication treatment, which reduced the escapes (asymptomatic and non visual detectable diseased trees) contributed for these results. It is important to note that these results were obtained with only small citrus plots (0.8–2.9 ha) and they cannot be extended to larger groves and farms amenable to HLB management by the symptomatic tree removal and vector control. 相似文献
130.
In this paper a general introduction is given to research advances in genetics improvement and breeding of Chinese aspen (Populus davidiana Dode) in China. This introduction includes natural distribution and collection, conservation, gene diversity, provenance
trial, crossing breeding, vegetative propagation and disease resistant etc. Based on the current situation of forest tree
breeding in China, some strategic suggestions concerning the future development of Chinese aspen genetics improvement in China
are presented, taking into consideration the existing domestic demands of forestry production and international trends in
forest tree breeding.
Responsible Editor: Chai Ruihai 相似文献