苎麻疫霉生物学性状遗传与变异研究

在实验室条件下研究了不同地区和不同寄主来源的苎麻疫霉（PhytophthoraboehmeriaeSawada）的菌落形态、菌丝线性生长速率（以下简称为生长速率）及同宗配合性状的遗传与变异，结果指出苎麻疫霉菌落形态和生长速率的遗传存在3种类型：（1）在单游动孢子后代和自交后代均可稳定遗传；（2）在单游动孢子后代稳定遗传而在自交后代发生变异；（3）在单游动孢子后代和自交后代均发生变异。结果表明，该菌菌落形态和生长速率的遗传具有多样性，上述两性状可以由细胞核杂合基因控制，也可以由细胞核纯合基因控制，还可能由细胞质因子控制。试验结果还指出，苎麻疫霉的同宗配合性状在单游动孢子和单卵孢后代均可稳定遗传，表明在供试的苎麻疫霉菌株中控制该性状的遗传因子是纯合的。

INHERITANCE OF BIOLOGICAL CHARACTERS IN PHYTOPHTHORA BOEHMERIAE SAWADA

The inheritance and variation of biological characters including growth rate, colony morphology and homothallism of Phytophthora boehmeriae sawada were studied in vitro. Six isolates obtained from different localities and host plants were used as the test microorganisms. The results showed that there were three patterns on inheritance of growth rate and colony morphology in P. boehmeriae: (1) The growth rate and colony morphology of isolates PM-8 and JX-9 from papermulberry (Broussonetia papyrifera) and cotton (Gossypium hirsutum) respectively, were all steadily inherited in both single-zoospore and single-oospore progenies, which indicated that the genetic factors controlling the two characters in the two isolates were homozygous, (2) The two characters of isolates JS-5 and ZH-8 from cotton and ramie (Boehmeria nivea) respectively, were steadily inherited in single-zoospore progenies but showed obvious variation in selfed singleoospore progenies, which suggested that the two characters of the isolates were controlled by nuclear heterozygous genes, (3) The growth rate and colony morphology of isolates RA-2 and CS-8 from ramie and cotton respectively, showed variation in both single-zoospore and single-oospore progenies, but the variation of growth rate in selfed oospore progenies was significantly different from that in zoospore progenies, which suggested that these characters might be controlled by cytoplasmic factors, moreover, the variation of growth rate in selfed oospore progenies also associated with nuclear genetic factors in the two isolates. The results also showed that the homothallic character of all the six isolates tested were steadily inherited in both asexual and sexual progenies, which suggested that the genetic factors controlling the character appeared to be homozygous.