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植物病害是指作物生产上重要而可防治的那种危害。在下述情况下,基因或胞质的同质性大大增加作物对病害的感染力:a)该种作物分布很广;b)作物对其侵袭有抵抗力的某种病原,具备有效的传布方式和经常从无毒性向有毒性转化的潜在遗传变异性;c)作物生长在对病害有利的环境条件下。对农业利大于弊的作物单一性,同时也存在着危险性。由于流行很罕见,目前的种质鉴定和利用办法虽则很好,但却可以改进。需要对病原及种质同抗病性基因及胞质问的关系作进一步地研究。许多种质原始材料对病害的反应尚未充分测定,也没有将有效抗病基因转移到适于农业的植物类型中。大部分病害的稳定抗病性,可以采用育种和基因分配来实现。普通抗病性、多因子抗病性、分带种植和多系都可被选用,但对植物育种和农业来说其中每项又各有优点和局限。在各种环境条件下对病原的不同小种进行国际性观测,是抗病育种的有力手段。种质的多样性对予防未知病害能起到某些保护作用。
Plant disease is the type of hazard that is important and preventable in crop production. The homogeneity of the gene or cytoplasm greatly increases the infectivity of the crop to the disease when: a) the crop is widely distributed; b) a pathogen that is resistant to the attack by the crop has an effective route of dissemination And the potential genetic variability that often translates from non-toxic to toxic; c) the crop is growing under environmentally-friendly conditions. The unity of crops that outweigh the benefits of agriculture is also dangerous at the same time. As the epidemic is rare, the current methods of germplasm identification and utilization are good, but they can be improved. The relationship between pathogen and germplasm and disease resistance genes and cytoplasm should be further studied. The reaction of many germplasm raw materials to diseases has not been adequately determined and no effective resistance genes have been transferred to plant types suitable for agriculture. Stable disease resistance of most diseases can be achieved by breeding and gene allocation. Common disease resistance, multi-factor disease resistance, zonal planting and multiple lines can all be used, but each has its advantages and limitations for plant breeding and agriculture. International observation of different races of different pathogenic species under various environmental conditions is a powerful tool for disease resistance breeding. The diversity of germplasm can play some protective role in preventing unknown diseases.