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1.
2.
对浙江省夏秋蚕品种薪杭,白云,丰1和54A等进行了充血复壮改良,基本稳定后的复壮系与现行生产系进行了生产性能的比较试验。结果表明复壮系在各项性状都有一定的提高,其中龄期经过,各品种的复壮系与生产系之间差别不大,只有薪杭丙和白云丙稍有延长。全茧量和茧层量基本上复壮系都比生产系有所提高。生命率差异比较大,奠中薪杭的复壮系低下生产系,差异达到显著水平,白云复壮系略微低于白云甲,但高于白云乙,丰1的复壮系与生产系无明显差异,54A则是复壮系高于生产系。良卵数除薪杭丙比薪杭甲略低外,其他品种的复壮系都比生产系显著提高,有的甚至达到极显著水平。说明复壮系在生产性能上有较大的改良,有一定的推广应用价值。 相似文献
3.
Aleksa Obradovic Athanassios Mavridis Klaus Rudolph Jaap D. Janse Momcilo Arsenijevic Jeffrey B. Jones Gerald V. Minsavage Jaw-Fen Wang 《European journal of plant pathology / European Foundation for Plant Pathology》2004,110(3):285-292
During the last two decades bacterial strains associated with necrotic leaf spots of pepper and tomato fruit spots were collected in Serbia. Twenty-eight strains isolated from pepper and six from tomato were characterized. A study of their physiological and pathological characteristics, and fatty acid composition analysis revealed that all of the strains belong to Xanthomonas campestris pv. vesicatoria. Being non-amylolytic and non-pectolytic, pathogenic on pepper but not on tomato, containing lower amounts of fatty acid 15 : 0 ante–iso, the pepper strains were designated as members of the A group of X. campestris pv. vesicatoria. However, the tomato strains hydrolyzed starch and pectate, caused compatible reactions on tomato but not on pepper, had higher percent of 15 : 0 ante–iso fatty acid, and were classified into B phenotypic group and identified as X. vesicatoria. PCR primers were developed which amplified conserved DNA regions related to the hrp genes of different strains of X. campestris pv. vesicatoria associated with pepper and tomato. Restriction analysis of the PCR product resulted in different patterns and enabled grouping of the strains into four groups. When xanthomonads isolated from pepper and tomato in Serbia were analyzed, they clustered into two groups corresponding to the grouping based on their physiological and pathological characteristics. According to the reaction of pepper and tomato differential varieties, the strains from pepper belong to races P7 and P8 and tomato strains belong to the race T2. All strains were sensitive to copper and streptomycin. Advantages and disadvantages of various bacterial spot management practices are discussed. 相似文献
4.
Quirico Migheli Elena Briatore Angelo Garibaldi 《European journal of plant pathology / European Foundation for Plant Pathology》1998,104(1):49-57
The RAPD fingerprinting procedure was used in combination with pathogenicity assays on differential cultivars to characterize a representative collection of 72 Fusarium spp. isolates of different geographic origin collected from diseased carnation. In F. oxysporum f. sp. dianthi, isolates were grouped according to the physiologic race: group 1 included isolates of race 4; group 2 was formed by isolates of race 2 and single representatives of races 5 and 6; group 3 included isolates of races 1 and 8. No correlation was found between RAPD data and geographic origin of the isolates tested: representatives of race 2 isolated in Italy, Israel and Japan had the same amplification profile. Three isolates which showed a low level of pathogenicity on all carnation cultivars tested shared an identical amplification pattern and are probably saprophytic F. oxysporum. Finally, two F. redolens isolates from Japan and seven non-pathogenic isolates of F. proliferatum collected from diseased carnation in Italy, Israel and The Netherlands were clearly distinguishable according to their RAPD fingerprint. The results are discussed in relation to previous studies on the genetic diversity of F. oxysporum f. sp. dianthi and to the development of forma specialis- and pathotype-specific diagnostic tools. 相似文献
5.
A total of 404 isolates of Xanthomonas campestris pv. vesicatoria , obtained from Capsicum chinense cv. West Indian Red grown in Barbados and Grenada, were differentiated into pathogenic races, and of these, 96 were tested also for selected taxonomic group phenotypes. The response of C. chinense to infection by several X. campestris pv. vesicatoria races and the contribution of races isolated from this cultivar to severity of bacterial spot of bell pepper and tomato were also investigated. P4T2, P5T2 and P6T2 were the predominant races of X. campestris pv. vesicatoria isolated from C. chinense grown in Grenada, whereas nine races (T1, P4, P6, P0T2, P1T2, P4T1, P4T2, P6T1 and P6T2) were isolated in Barbados. Race P4T2 comprised 46.0 and 71.4% of the isolates from Barbados and Grenada, respectively. The 96 isolates, all of which overcame resistance conferred by the gene Bs2 , shared taxonomic group B strain characteristics, including the presence of the β-protein band, positive amylolytic activity and inability to oxidize cis -aconitate. The C. chinense cv. West Indian Red was susceptible only to races of X. campestris pv. vesicatoria that can overcome Bs2 gene resistance. Of six such races identified in Barbados, only P4T1, P4T2 and P6T1 affected bacterial spot-susceptible bell pepper or tomato in the field, and they amounted to only 1.5–2.1% of each sample of isolates from these plant species. Moreover, they were confined to the smallest bacterial spot lesions. Bell pepper was most severely affected by combinations of races T1 with P3T2 and T2 with P0T1, and tomato by race T1 only and combinations of races P0T1 with P0T2 and P1T1 with P1T0, all of which prevailed in the field despite selection against them by C. chinense cv. West Indian Red. 相似文献
6.
The development of apple varieties displaying durable resistance against powdery mildew is one of the major aims in apple breeding programmes worldwide. For a reliable judgment of the resistance of different Malus genotypes, an extended knowledge about the virulence of the pathogen is necessary. To prove the existence of physiological races of Podosphaera leucotricha , 31 monoconidial isolates of the obligate biotrophic fungus representing five locations within Europe have been established and maintained over a period of 3–4 years. The isolates were maintained on in vitro shoots of the highly susceptible apple cv. Gibb's Golden Gage. An AFLP-based DNA fingerprinting protocol was developed and, using 54 stably reproducible AFLP markers, a dendrogram revealed genetic variability among different isolates of P. leucotricha . Although the molecular characterization of the isolates showed an overall low level of genetic variability, the high phenotypic diversity among European isolates suggest that sexual reproduction may also be involved in the disease cycle of the pathogen in Europe. Phytopathological tests using detached leaves of a collection of 36 Malus genotypes allowed the differentiation of five selected isolates by their virulence patterns. A high level of diversity in terms of virulence was obtained in P. leucotricha. From the present study, based on apple breeding germplasm, cultivars and Malus species, it can be concluded that physiological races of P. leucotricha do indeed exist in Europe. 相似文献
7.
苏州大学蚕桑研究所发明现行蚕品种转育成荧光茧色判性蚕品种的方法,新育成的蚕品种“雄晓”雄茧为黄荧光,雌茧为紫荧光,判性率100%。茧质成绩:全茧量1.499g,茧层量0.366g,茧层率24.42%,具生产实用性。 相似文献
8.
J. A. Lane T. H. M. Moore D. V. Child K. F. Cardwell B. B. Singh J. A. Bailey 《Euphytica》1993,72(3):183-188
An in vitro growth system was used to determine the virulence of two samples of Striga gesnerioides from Zakpota in southern Benin. Cowpea variety B301, previously considered resistant to all races of S. gesnerioides, was susceptible to both samples of the parasite. Two other cowpea varieties, 58–57 and IT81D-994, were totally resistant. Resistance in 58–57 was associated with a hypersensitive necrosis of infected roots, whilst IT81D-994 supported production of small S. gesnerioides tubercles with stems which failed to develop. Striga gesnerioides from southern Benin is the fourth race of the parasite to be identified, and the first with virulence on variety B301. The implications for breeding cowpeas with resistance to S. gesnerioides are discussed.Abbreviations IITA
International Institute of Tropical Agriculture
- LARS
Long Ashton Research Station
- SAFGRAD
Semi-Arid Food Grain Research and Development 相似文献
9.
Patterns of shoot elongation of 2-yr seedlings from native North American populations of ponderosa pine and Douglas-fir were compared to those of Argentine land races originating from unknown provenances. The comparisons were conducted in Moscow, Idaho (USA), and suggested that the ponderosa pine land race was descended from a California provenance at low or middle elevations but that the growth potential of the land race was only mediocre in comparison to eight native populations. The Douglas-fir land race exhibited a relatively high growth potential in comparison to 19 native provenances and undoubtedly originated from a mild coastal environment. The results provide concrete recommendations for upgrading the growth potential of the Argentine land races by importing germ plasm of specific provenances. 相似文献
10.
河北省西瓜枯萎病菌生理小种分化及其分布 总被引:3,自引:0,他引:3
采用国际公认的鉴别寄主Sugar Baby、Charleston Gray和Calhoun Gray的病株率作为抗性分级标准,对采集于河北省西瓜种植区46个县(市)的西瓜枯萎病菌系进行了致病性测定。根据鉴别寄主对供试菌系的抗感反应,将46个西瓜枯萎病菌系划分为0号、1号和2号3个不同的生理小种,分别包括8,30和8个菌系,占供试菌系的17.4%、65.2%和17.4%;0号生理小种菌系致病性最弱,仅使品种Sugar Baby感病,以冀中和冀南居多;1号生理小种菌系致病力中等,使鉴别寄主Sugar Baby和Charleston Gray感病,而使Calhoun Gray抗病,分布在整个河北省西瓜种植区;2号生理小种的菌系致病力最强,使3个鉴别寄主均能感病,主要分布在冀中和冀北。 相似文献