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71.
Seishi Akino Masayasu Kato Kiyotaka Gotoh Shigeo Naito Akira Ogoshi 《Journal of General Plant Pathology》2005,71(3):200-203
The genetic characteristics of the dominant genotypes of Phytophthora infestans in Japan (US-1, JP-1, Japanese A1-A, A1-B) were compared. Differences were evident in the peptidase genotype, amplified fragment length polymorphism, and RG57 DNA fingerprints. Almost all of the fingerprint bands for the Japanese genotype A1-B were also present in JP-1 and Japanese A1-A, and few bands were unique to Japanese A1-B. These results suggest that the Japanese A1-B genotype was generated from sexual reproduction involving Japanese A1-A and JP-1 or related genotypes. 相似文献
72.
73.
大青杨群体变异及其选择的研究 总被引:4,自引:1,他引:4
大青杨种内群体间变异十分丰富,为了选出最佳群体,直接用于造林,进行了全分布区群体选择的研究。本试验在大兴安岭地区对9个产体群体的大青杨做了生长、生根、抗寒、抗锈病的主要经济性状的测定,然后进行综合评定,选择出最佳群体。 相似文献
74.
75.
A sample of 602 street dogs captured by the São Paulo zoonosis-control municipal service was analyzed for the presence of serum antibodies against the rabies virus and compared to a control sample of 37 dogs from the kennel of the police of São Paulo. Data were stratified into 4 age intervals and the age from the street-dog sample was estimated by general aspects and dental observation according to standard techniques. We assumed that seropositivity was due to previous vaccination (no sub-clinical infection). From the prevalence data, we estimated the age-dependent incidence-density rate of vaccination by a simple mathematical model, which also allowed the estimation of the period of antibody protection given by the supposed vaccination. Crude seroprevalence in the street-dog sample was 16.5% and in the sample from the police-kennel dogs was 80%. The average age of first vaccination calculated for the street-dog sample was 5 years of age (if we assumed an average period of vaccine protection of 3 years) — but 5 months of age for the police-kennel sample. 相似文献
76.
A restricted maximum likelihood analysis applied to an animal model showed no significant differences (P > 0.05) in pH value of the longissimus dorsi measured at 24 h post-mortem (pH24) between high and low lines of Large White pigs selected over 4 years for post-weaning growth rate on restricted feeding. Genetic and phenotypic correlations between pH24 and production and carcass traits were estimated using all performance testing records combined with the pH24 measurements (5.05–7.02) on slaughtered animals. The estimate of heritability for pH24 was moderate (0.29 ± 0.18). Genetic correlations between pH24 and production or carcass composition traits, except for ultrasonic backfat (UBF), were not significantly different from zero. UBF had a moderate, positive genetic correlation with pH24 (0.24 ± 0.33). These estimates of genetic correlations affirmed that selection for increased growth rate on restricted feeding is likely to result in limited changes in pH24 and pork quality since the selection does not put a high emphasis on reduced fatness. 相似文献
77.
78.
赞皇大枣的群体遗传多样性评价 总被引:1,自引:1,他引:1
为了探明三倍体赞皇大枣的遗传基础,利用22个多态性引物对赞皇县及周边县区的50个赞皇大枣类型、26个酸枣类型、8个枣品种等3个群体进行了RAPD扩增,共扩增285个位点。遗传多样性分析表明:赞皇大枣群体的多态性位点百分率为58%,小于枣品种群体(66%)和酸枣群体(89%);赞皇大枣群体共扩增出205种带型,而酸枣群体扩增出416种带型;赞皇大枣群体内平均遗传距离为0.087,小于枣品种群体(0.181)和酸枣群体(0.254)。说明:赞皇大枣的遗传多样性小于枣品种群体,酸枣群体有较丰富的遗传背景。 相似文献
79.
Black-tailed prairie dogs (Cynomys ludovicianus) currently live in metapopulations in the parts of their range where plague, caused by the bacterium Yesinia pestis, has invaded. Prairie dogs are highly susceptible to the pathogen, with most animals within towns dying during Y. pestis outbreaks. A review of population genetic studies of prairie dogs demonstrates considerable differentiation between prairie
dog towns. Despite declines and fluctuations in size of prairie dog populations, they continue to harbor considerable genetic
variation. This results from continual dispersal and gene flow, likely along low-lying drainages that connect towns. When
combined with estimates of population size, the landscape genetic approach described here will provide precise estimates of
dispersal and gene flow, in addition to evaluation of long-term stability of prairie dog metapopulations. 相似文献
80.
Dead wood is a critical resource for biodiversity in boreal forests. We analysed the persistence of five model species inhabiting
dead wood. By parameterising a metapopulation model (the incidence function model), the model species were all assigned characteristics
that makes it likely that they have disappeared from some (20%) forest landscapes with a long history of forest management.
In the metapopulation model, a forest stand (5 ha) was regarded as a habitat patch. The amount of habitat in each patch was
obtained from models of dead wood dynamics of Norway spruce in central Sweden. Dead wood generated by altered management over
the entire landscape was found to be less efficient in reducing extinction risks in comparison to the same amount of dead
wood generated by protecting reserves. Because generation of dead wood by altered management is often less expensive than
setting aside reserves, it is difficult to determine which conservation measure is most cost-efficient. In a landscape subjected
to forestry for the first time, it was better to preserve a few large reserves than many small ones. However, in a managed,
highly fragmented forest landscape it was better to set aside many small reserves. The reason for this was that small plots
with high habitat quality could be selected, while large reserves originally contained habitats both of high and low quality,
and the rate of habitat quality increase was low. A strategy for biodiversity conservation in a managed forest landscape should
include information about the history of the landscape, the current amount and spatial distribution of forest habitats, and
the potential for rapid restoration of forest habitats, both on managed and unmanaged forest land. 相似文献