Periodicity and gradients in dispersal ofAlternaria linicola in linseed crops     

I. Vloutoglou  B. D. L. Fitt  J. A. Lucas 《European journal of plant pathology / European Foundation for Plant Pathology》1995,101(6):639-653

Conidia ofAlternaria linicola produced on infected linseed crops were mainly dispersed by wind. The numbers of conidia in the air above linseed crops collected by a Burkard spore sampler were greatest between 1200 h and 1300 h, when the relative humidity was lowest. Although numbers of conidia collected decreased with increasing height within and above the crop canopy, air-borneA. linicola conidia were present up to 80 cm above the crop canopy. Conidia ofA. linicola were transported by wind up to at least 40 m downwind from an artificial line inoculum source, but their numbers decreased with increasing distance from the source. In 1991, 1992, and 1993, the dispersal ofA. linicola conidia above linseed crops followed a seasonal periodicity which was influenced by weather conditions and cultural practices. The greatest numbers of conidia were collected during July, August and early September and coincided with periods favourable for sporulation and with an increase in the incidence of the disease in the senescent crop. Air-borneA. linicola conidia produced on point or line inoculum sources (naturally infected linseed stem debris) were responsible for the spread of the disease in linseed crops. In 1992 and 1993, the disease was first detected downwind from the sources, but by the end of the growing seasons, it had spread in all directions and up to 20 m and 60 m from the sources, respectively. Disease gradients were initially steep near the inoculum sources but they became flatter with time due to the secondary spread of the disease.  相似文献   

通径分析在油纤兼用亚麻产量分析中的应用     

刘海龙  王世发  周玉萍  牛海龙  刘淑莲  潘亚丽  孙晓平  徐迟 《安徽农业科学》2012,40(11):6416-6417,6419

首先对18个胡麻(Linum usitatissimum Linn.)品系的5个产量构成性状及产量进行相关分析,指出单株粒数和分枝长与产量之间的相关性达显著水平,并且各性状之间还存在着相互作用、相互制约和相互促进的关系。因此对吉林省胡麻产量及其构成性状的关系须采用通径分析方法进行分析,以估算每一个性状对产量的直接作用,以及一个性状通过另一个性状对产量的间接作用。通径分析结果表明,在吉林省提高胡麻产量,可主要通过提高单株粒数和增加分枝数来实现;返青将致使胡麻减产。  相似文献   

Infection of Linseed by Alternaria linicola; Effects of Inoculum Density, Temperature, Leaf Wetness and Light Regime     

I. Vloutoglou  B.D.L. Fitt  J.A. Lucas 《European journal of plant pathology / European Foundation for Plant Pathology》1999,105(6):585-595

Controlled environment studies were conducted to determine the effects of inoculum density, temperature, leaf wetness and light regime on the infection of linseed by Alternaria linicola. The % cotyledons and leaves with symptoms, and the disease severity (% leaf area with symptoms) increased linearly when the inoculum density increased from 1×10³ to 1×10⁵ conidiaml^–1. The first symptoms appeared on cotyledons and leaves 4 and 6 days after inoculation, respectively. Eight hours of leaf wetness were sufficient to initiate the disease at 25°C but not at 15°C, when 10-h periods of leaf wetness were required. % leaf area with symptoms was lower at 15°C than that at 25°C irrespective of the leaf wetness periods tested. Interruption of a continuous leaf wetness period by a 12-h dry period, occurring at any time between 1 and 18h after inoculation, decreased the % cotyledons with symptoms and the disease severity, with the greatest reductions (60% and 100%, respectively) being observed when the dry period began 6h after inoculation. A. linicola conidia were able to exploit successive 12-h periods of leaf wetness cumulatively to infect linseed plants. Disease incidence and severity were positively correlated with the dark period following inoculation, but they were negatively related to the length of the initial light period. Our findings suggest that infection of linseed by A. linicola and further development of symptoms can occur under unfavourable environmental conditions.  相似文献   

Production and characterisation of monoclonal antibodies to cell wall components of the flax rust fungus     

Leanne J. Murdoch  Issei Kobayashi  Adrienne R. Hardham 《European journal of plant pathology / European Foundation for Plant Pathology》1998,104(4):331-346

Monoclonal antibodies have been raised against an haustorium-enriched sample prepared from flax leaves infected with the biotrophic flax rust pathogen Melampsora lini. The monoclonal antibodies were produced following conventional and co-immunisation procedures and the range of antibody specificities was compared. The preparation used as immunogen for the conventional protocol was a crude isolate of haustoria consisting of approx. 65% fungal haustoria, the other components being mainly mesophyll cells or cell wall and chloroplast fragments. Following hybridoma production, 40% of positive cell lines produced antibodies that reacted with haustoria and other fungal cells, but 60% bound to plant cells in the infected leaves. For the co-immunisation protocol, the preparation used for immunisation consisted of the crude isolate of haustoria mixed with serum raised against an haustorium-depleted leaf homogenate. In two fusions, 92-94% of the antibodies reacted with fungal cells, including 3 cell lines that localised specifically to the cell wall of haustoria. Only 6-8% of the antibodies produced via co-immunisation reacted with plant cells. The antigens targeted by the three haustorium-specific monoclonal antibodies are incorporated into the wall at early stages of haustorium development, remain in the wall throughout haustorium maturation, and are present in both compatible and incompatible interactions. The epitopes recognised by the monoclonal antibodies are oligosaccharide in nature and the antigens are highly resistant to extraction from the wall. These results highlight the value of the co-immunisation protocol for the production of monoclonal antibodies to specific components in an impure preparation and provide direct evidence for molecular differentiation within the wall of the haustorium of M. lini.  相似文献   

亚麻萌发期耐盐鉴定体系优化及150份种质耐盐性综合评价     

李枭  郭栋良  李恭泽  薛敏  江海霞  叶佳丽  谢丽琼 《新疆农业科学》2022,59(6):1438-1449

【目的】 优化亚麻萌发期耐盐鉴定体系并综合评价种质资源耐盐性,为亚麻种质资源耐盐性评价及耐盐品种培育奠定基础。【方法】 选用芽长、根长和发芽率作为亚麻萌发期耐盐性鉴定的表型性状。利用13个NaCl浓度梯度胁迫处理30份亚麻种质,分析不同指标变化确定胁迫浓度。用确定的浓度对150份亚麻种质进行胁迫,分别统计相对芽长、相对根长和相对发芽率,利用隶属函数法对供试亚麻萌发期耐盐性进行综合评价,结合聚类分析划分耐盐等级。【结果】 以相对芽长或相对根长为指标时适宜的NaCl胁迫浓度为100 mmol/L,以相对发芽率为指标时适宜的NaCl胁迫浓度为220 mmol/L;150份亚麻种质分划为5个耐盐等级:高耐3份、耐盐36份、中耐67份、敏感33份、高敏11份;油用亚麻亚群中各指标均显著高于纤维亚麻和兼用亚麻。【结论】 不同耐盐指标的最适筛选浓度不同。筛选出的3份高耐亚麻种质可用于亚麻耐盐育种及后续研究。油用亚麻相比兼用和纤用亚麻更耐盐。  相似文献   

Importance of sepals in fruit and seed development in linseed (Linum usitatissimum L.)     

D. P. S. Tomar  P. S. Deshmukh  S. K. Sinha 《Euphytica》1979,28(3):739-745

Summary The green sepals in linseed (Linum usitatissimum L.) persist till almost the time of fruit ripening. Since the plant retains very few leaves and the fruits are better exposed to receive sunlight, the green sepals may be important in fruit and seed development. Influence of the removal of 0, 1, 3 and 5 sepals on the day of anthesis, 7, 15 and 25 days after anthesis on fruit and seed development was examined. Excision of all the fine sepals on the day of anthesis stopped fruit and seed development in the varieties M 10 and NP (RR) 45 but in Mukta the reduction was about 55%. Removal of three sepals also decreased fruit growth in Mukta and NP (RR) 45. The effect of removal of sepals was more pronounced on the number of seeds per fruit than on seed weight. Sepals fixed ¹⁴CO₂ and translocated ¹⁴C to seeds. However, the ¹⁴CO₂ fixation was maximum at early stages of fruit development, whereas a higher percentage of the fixed ¹⁴C was translocated at later stages of growth. It is suggested that the sepal size in linseed could be a useful selection criterion.  相似文献   

Comparison of pedigree selection and single seed descent for oil yield in linseed (Linum usitatissimum L.)     

Graciela Salas  W. Friedt 《Euphytica》1995,83(1):25-32

Summary Four populations of linseed derived from five parents were advanced from the F₂ to the F₆ generation by SSD and to the F₅ by pedigree selection. These populations were used to compare the efficiency of the two methods in order to provide superior genotypes with respect to grain yield and oil content, i.e. oil yield. The results showed minimum differences between pedigree and SSD lines for grain yield, where in only one cross the SSD lines were significantly superior to the pedigree lines. Since pedigree selection was carried out for both, seed yield and oil content, a positive response to selection was expected. However, early selection for yield, a character with low heritability, was not successful. On the contrary, significant differences for oil content were detected between the two groups of lines in three of the four crosses studied. In these cases the pedigree lines were superior to the SSD lines. These results demonstrate that strict selection in early generations for oil content, a character with comparatively high heritability, is feasible and successful in linseed. However, selection for seed yield should be postponed to later inbred generations. Consequently, in breeding for maximum oil yield of linseed a two-step selection procedure is recommended.Abbreviations PS pedigree selection - SSD single seed descent - TGW thousand grain weight  相似文献   

Variation of cultivated flax (Linum usitatissimum L. subsp.usitatissimum) and its wild progenitor pale flax (subsp.angustifolium (Huds.) Thell.)     

A. Diederichsen  K. Hammer 《Genetic Resources and Crop Evolution》1995,42(3):263-272

The domestication of cultivated flax (Linum usitatissimum L. subsp.usitatissimum) is briefly discussed. Using data documented as a matter of routine in genebank work, 63 accessions of cultivated flax from the flax germplasm collection of the Gatersleben Genebank are compared with 73 accessions of its wild progenitor pale flax (subsp.angustifolium (Huds.) Thell.), which have been observed in systematic field trials. Range of variation, genetically based variation, heritability and correlation of several characters are considered, especially with respect to the influence of domestication. Cultivated flax shows higher variation in the characters of generative plant parts, while pale flax varies more in the vegetative parts of the plant. The character correlations are similar in both subspecies. Of the 29 characters studied in pale flax the parameters describing tillering, height of plant, weight of seeds, width of petals and width of leaves are especially suitable for distinguishing between different accessions. In spite of the high heritabilities of most of the characters, the influence of the environment is significant in most cases.  相似文献   

猕猴桃病害的发生规律及其综合防治措施     

方绍正  徐祖明 《安徽农业科学》2006,34(22):6060-6062

简要概述了猕猴桃常见病害的症状、病原及发生规律,并在此基础上提出了相应的综合治理措施。  相似文献   

石海椒愈伤组织诱导与增殖研究     

古玉  许强  李龙  GU Yu  XU Qiang  LI Long 《北方园艺》2011,(9):130-134

对石海椒幼嫩叶片和茎段进行了愈伤组织的诱导增殖研究,以期探寻其诱导和增殖的最佳条件。结果表明:石海椒的叶片和茎段都能诱导出愈伤组织,但最佳外植体为叶片,叶片和茎段在0.1%升汞中适合消毒时间为6 min和10 min。叶片最适诱导培养基为B5+0.6 mg/L6-BA+2.0 mg/L NAA,增殖培养基为B5+0.6 mg/L 6-BA+1.25 mg/L NAA。基本培养基和生长调节剂对愈伤诱导的影响是NAA>6-BA>基本培养基。  相似文献