| 摘要: |
| 本文以小麦锈菌群体毒性结构和变异方面的研究进展为例,评介了植物—病原菌群体遗传学的原理和方法。采用单基因系作鉴别寄主后,就能够确定锈菌毒性基因组成及其频率。Groth提出的理论模型描述了品种变动所引起的锈菌毒性频率的变化,但小麦秆锈菌二十余年的田间标样分析表明,毒性变化状况更为复杂,寄主抗病性也并非影响毒性变化的唯一因素。Vanderplank用定向选择和“稳定化选择”解释病菌毒性频率的变化,但大量精细实验和小种鉴定结果提供了不利于这一假说的证据。虽然由于人们对植物和病原菌群体间相互作用的遗传学和生物学细节知之甚少,现在还不能对此得出最终结论,但这不表明Vanderplank可能是完全正确的。 |
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| GENETIC CHANGE OF VIRULENCE IN WHEAT-RUST POPULATIONS |
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| Abstract: |
| This review discusses principle and methodology of population geentics of host-parasite and centers mainly on genetic change of virulence in wheat-rust populations.By means of analysing the reactions of rust on single gene differentials the virulence structure and frequency can be determined.Groth's idealized curve describes virulence frequency dynamics of cereal rust fungi due to manipulation of the population of host plants by humans.Field data of stem rust of wheat over 20 years demonstrated more complicated features of virulence change and indicated that host resistance was not the only factor influencing that change.Vanderplank put forth directional selection and "stabilizing selection" as the forces keeping virulence frequency changing.Evidences from carefully designed experiments and large scale rust survey raise serious doubts concerning the validity of Vanderplank's hypothesis,but the final conclusion can not be reached because of the poor understanding of genetics and biology of host-parasite interaction at population level. |
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