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1.
病毒病引起农业生产中的严重损失。目前用于病毒病防治的方法主要有:种质资源的利用、利用杀虫药剂防治病毒传毒介体-昆虫或诱导植物产生抗病毒物质、通过遗传修饰的方法获得抗病毒病作物品种。本文对这些方法进行了综述,并对其优缺点和应用价值进行了评述。  相似文献   

2.
The amplification efficiency and identification diversity with gene-specific primers derived from S locus glycoprotein gene (SLG) and S locus receptor kinase gene (SRK) were compared, and the geographical distribution for S haplotypes was investigated by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) in 72 genotypes of 5 Brassica vegetables from China. The amplification efficiency and identification diversity with class I SRK primers were generally higher than that with class I SLG in most crops tested. Class I alleles were found in total 66 genotypes and they were classified into 16, 10, 7 and 10 groups for Chinese cabbage, purple flowering stalk, cauliflower and cabbage respectively. The number of amplification accessions and identification diversity using the primers of class II SLG and SRK were quite similar. Class II alleles were detected in 55 genotypes and further grouped into one type in mustard and three in other crops. The nucleotide sequences showed high similarity between identical S haplotypes determined by reciprocal pollination and PCR-RFLP tests. It demonstrated that the PCR-RFLP analysis was feasible for identification of S alleles, and SRK should be considered as a better marker for the identification of S haplotypes than SLG. The types of S haplotypes are highly diverse in Brassica vegetables from China. Nevertheless, they were geographically limited in some Brassica vegetables, so the exchange of germplasm resources should be enhanced for breeding.  相似文献   

3.
Widespread adoption of genetically modified glyphosate-resistant (GR) crops in the US has dramatically changed the agricultural landscape to one that selects for establishment and spread of weedy species resistant to glyphosate, a commonly applied herbicide. Weed species that possess the means to readily spread across the landscape will be contained by weed management strategies that limit weed establishment and prevent seed set. An empirically-derived simulation model was developed to explore GR Conyza canadensis spread in relation to characteristics of the agricultural landscape. C. canadensis seeds are carried in the wind and move among fields and therefore, access high quality habitat (GR crops) at long distances. The baseline scenario was the current GR adoption levels in many US agricultural landscapes with corn and soybean rotated annually. Alternate scenarios examined the interacting effects of management uniformity (GR crop adoption) and increased landscape richness (three crops: corn, soybean, alfalfa, instead of two), over a 10 year simulation period. When landscape uniformity increased (increased GR corn adoption), 3× more fields would be infested with the resistant biotype and a specific field would have up to 24% greater likelihood of being infested compared to the current GR crop adoption levels. Increased landscape richness (adding alfalfa as a third crop) slightly decreased GR C. canadensis abundance. Reduced GR management uniformity by way of reducing GR soybeans to half their current adoption levels had the greatest impact on spread and prevented GR C. canadensis from reaching high abundance. Large-scale reliance on glyphosate for weed management has increased high-fitness habitat and will result in rapid spread of glyphosate-resistant weeds. Without significant reductions of glyphosate use and without spatial coordination of weed and crop management practices, GR weeds will continue to spread rapidly and impact agricultural practices in areas reliant on glyphosate.  相似文献   

4.
Many Brassicaceae species are economically important crops and Xanthomonas campestris pv. campestris (Xcc), the causal agent of black rot, is considered one of the most important necrotrophic plant bacterial diseases occurring worldwide on these and many other crops. Therefore identifying resistance mechanisms and genes is crucial. Researchers continue to investigate the role of phytochemicals (plant secondary metabolites) in protecting plants against diseases and pathogens. Glucosinolates (GLS), and more specifically their hydrolysis products, are known to have various biological effects including antimicrobial activity. From the positive results of initial in vitro studies with Xcc and other pathogenic bacteria new experiments were designed to evaluate the possible in planta role of GLS, and also phenolics, in the interaction with Xcc. The in planta studies, with various Brassicaceae seedlings, have shown a correlation between GLS profiles, and therefore the subsequent hydrolysis products, and the inhibition of Xcc growth. There were no significant correlations between Xcc infection and total phenolics. Positive correlations were found between specific and total GLS contents and the severity of disease. Further in vitro and in planta studies need to be performed to evaluate the role of GLS and other defense mechanisms in Xcc and other important bacterial infections of Brassicaceae crops.  相似文献   

5.
In the present study, phenotypic variability of 80 plum (Prunus domestica L.) varieties maintained in the French National Plum Collection was evaluated with 19 quantitative traits. In addition, genetic diversity and genetic structure was studied in three plum species (P. domestica L., Prunus cerasifera Ehrh. and Prunus spinosa L.) using chloroplast DNA (cpDNA) markers and five single sequence repeat (SSR) loci. Based on phenotypic traits, some varieties, such as mirabelle plums, grouped together. Bayesian structure analysis was used to identify different genetic groups, whereby damson plums were clearly distinguished from greengage plums. When examining the three species together, a higher level of cpDNA allelic richness was found in P. cerasifera and in P. spinosa than in P. domestica where only five cpDNA haplotypes were detected in the national plum collection, with one main haplotype that accounted for 80% of the varieties studied. P. domestica cpDNA haplotypes tended to group together with P. cerasifera haplotypes whereas most of P. spinosa haplotypes formed a separate cluster. SSR markers were somewhat able to distinguish the three species. These results provide some clues as to the origin of plum and the various plum varieties. Our results also provide useful information for the management of plum genetic resources.  相似文献   

6.
根肿病是由根肿菌属根肿菌（Plasmodiophora brassicae Woron.）侵染引起的专性寄生土传病害，主要危害十字花科作物，是十字花科作物重要病害之一。就中国白菜类蔬菜的根肿病菌生物学特性、分类，防治措施，抗根肿病基因的挖掘及抗病品种育种相关研究进行综述，全面了解根肿菌的侵染原理、存活条件、鉴定方法和大白菜抗根肿病基因的定位、克隆与辅助育种工作，剖析了抗病育种工作存在问题，并探讨展望相应对策，旨在为大白菜抗病育种工作的开展提供参考。  相似文献   

7.
Field and pot experiments were conducted to evaluate the effect of co-cultivation and crop rotation on the growth and corm rot disease of gladiolus (Gladiolus grandiflorus sect. Blandus) cv. Aarti caused by Fusarium oxysporum f.sp. gladioli (Massey) Snyd. and Hans. In the field experiment, gladiolus was co-cultivated with 10 agricultural/horticultural crops viz. Allium cepa L., Brassica campestris L., Capsicum annuum L., Eruca sativa Mill., Helianthus annuus L., Tagetes erectus L., Zea mays L., Vinca rosea L. and Rosa indica L., in a soil infested with F. oxysporum. All the crops except V. rosea and R. indica reduced disease incidence. The effect of H. annuus and T. erectus was significant and more pronounced than other co-cultivated crops. In general, root and shoot dry biomass, corm fresh weight, number of cormlets and number of flowers per spike decreased as compared to the un-inoculated monoculture gladiolus treatment (negative control) but these parameters enhanced as compared to the F. oxysporum inoculated monoculture gladiolus treatment (positive control). In a pot experiment, all the crops of the field experiment except V. rosea and R. indica were sown in rotation with gladiolus. Pot grown plants of different species were harvested at maturity and the soil was inoculated with F. oxysporum. Gladiolus was cultivated 1 week after inoculation. Disease incidence was significantly suppressed in all the treatments ranging from 29% to 53%. The highest suppression of disease incidence was recorded in T. erectus (53%) followed by B. campestris (49%). The effect of preceding crops on various vegetative parameters was similar in the pot experiment to that of the field experiment. The present study suggests that corm rot disease of gladiolus can be managed by mixed cropping of H. annuus and T. erectus or cultivation of T. erectus and B. campestris in rotation.  相似文献   

8.
Consumption of plants of the species Brassica oleracea is related to a decreased incidence of certain cancer forms in humans, and this has been linked to the presence of glucosinolates in those vegetables. After ripe seeds, sprouts of some brassicaceous plants contain the highest concentration of these compounds and are therefore a good source of glucosinolates for chemoprotection. In the present experiments, the content and distribution of glucosinolates was determined in ripe seeds and sprouts (seedlings) of five varieties of B. oleracea (white cabbage, red cabbage, Savoy cabbage, broccoli and cauliflower) by high performance liquid chromatography. The type and concentration of individual glucosinolates varied according to variety of B. oleracea, plant parts in which they occurred and the sprouting period of the seed. Concentration of alkyl glucosinolates decreased whereas that of indol-3-ylmethylglucosinolates increased throughout the sprouting period. Roots had the highest glucosinolate concentration in four and seven day old sprouts whereas at both sprouting times, cotyledons had the highest concentration of alkylthio- and alkylsulphinylglucosinolates.  相似文献   

9.
The physico-chemical properties and antioxidant capacity of the five main jujube varieties: Junzao, Lingbaozao, Jinzao, Zanhuangzao and Lizao collected from loess plateau of China were determined. The analyzed components included fruit yield, moisture content, total mass per fruit, pH, titratable acidity (TA), reducing sugars, total sugars, total soluble solids (TSS), ascorbic acid, total phenolics content, total flavonoids content and several pure phenolic compounds. The output of the analyses showed higher amounts of ascorbic acid and phenolics in these jujube varieties than in some common fruits. The antioxidative capacity of the jujube extracts, evaluated with the reducing power, the β-carotene bleaching, the 2,2-diphenyl-1-picrylhydracyl (DPPH•), and the 2,2′-azinobis (3-ethylbenzothiazoline-6-sulfonicacid) (ABTS•+) scavenging methods, showed that the antioxidant activity of the extracts of Lingbaozao was excellent for free radical scavenging and a potent natural antioxidant of commercial value. Statistically significant differences were observed between jujube cultivars investigated with regards to the measured parameters except rutin content of fruit. These results demonstrated that the cultivar was the main factor which influences the physico-chemical properties and antioxidant activity of jujubes.  相似文献   

10.
To clarify the variation and characteristics of polyphenolic compounds in Malus germplasm, and also to provide a theoretical basis for the application of apple landraces in China, polyphenolic compounds and concentrations were analysed in 103 Malus accessions from China using ultra performance liquid chromatography and liquid chromatography-mass spectrometry. The apple landraces of North China, which should have undergone more artificial selection than those of Northwest China and Northeast China, are used as table fruit, or as parents for breeding table varieties with high polyphenolic concentrations from. Wild species have been appropriated as parents for historical hybridisation of new genetic resources with high polyphenolic concentrations. The apple landraces ‘Bandayulenggunzi #1’ and ‘Duanzhigunzi’ possess the greatest concentrations of total polyphenols detected, and so could be used as table fruit by consumers directly, or as parents for breeding varieties with high polyphenolic concentrations from by breeders. The apple landraces originating from North China, Northwest China and Northeast China, are significantly separated by linear discriminant analysis (LDA), and the wild species and apple landraces are evidently discriminated by LDA as well. Hierarchical cluster analysis of polyphenolic compounds of Malus accessions resulted in clusters derived from closely-related biochemical pathways.  相似文献   

11.
《Scientia Horticulturae》2005,103(4):403-412
The objective of this work was to determine a standardised sampling plan for Bemisia tabaci Genn. (Homoptera: Aleyrodidae) in outdoor tomatoes. Eight commercial crops of tomato in the Municipalities of Coimbra and Viçosa, Minas Gerais State, Brazil were used to assess the density of nymphs and adults of B. tabaci on tomato leaves. Twelve sampling methods were compared. Each consisted of one of two sampling techniques (beating tomato leaves in plastic trays and direct counting of insects on leaf surfaces), one of three sizes of sampling units (one, two and three leaves) in either the apical and basal parts of the canopy of tomato plants. The most appropriate sampling methods were beating one apical leaf in the tray to assess adults and by direct counting of nymphs on a basal leaf of tomato plants. The number of samples, when estimating the population density with a specified precision level equal to 20%, was 45 samples/plantation for nymphs (Kcommon = 0.737) and 24 samples/plantation for adults of B. tabaci (Kcommon = 1.10).  相似文献   

12.
Fruits play a crucial role in human diets and as a commercial commodity in trade. The consumers have considered fruit quality as the most important criteria that decides its acceptability. Fruit quality-based overall acceptability determines the success of any breeding programme, as a number of improved varieties with desired traits including resistance to stresses could not be popularized due to their poor quality fruits. However, breeding for quality improvement in perennial fruit crops is hampered by a number of limitations including large size of the plant, long juvenile phase and environmental problems (e.g. fruit drops due to natural calamities). Besides, fruit quality is a polygenic trait, which is quantitatively inherited and thus making breeding programme complicated in quality improvement of fruit crops. Several attempts have been made to improve the quality characters in annual staple crops, however this aspect is conveniently ignored in case of perennial fruit crops. A balanced approach combining conventional and non-conventional breeding techniques could help in addressing this issue. The biotechnological approaches provide precision, reliability and are considered to reduce the breeding cycle in long duration crops. Efficacy of approaches like marker assisted selection, candidate gene, genomics, trangenics, cisgenics has shown to be advantageous when dealing with cumbersome crops. This review would focus on problems in fruit breeding and present status of different breeding approaches for fruit quality improvement in fruit trees.  相似文献   

13.
Five watermelon varieties with different flesh colors: “ZAOHUA” (red); “96B41” (pink); “307CHAOFENG” (yellow); “UNKNOWN” (orange); and “SANBAI” (white) were used to investigate the relationship between carotenoid profiles and expression of carotenoid-related genes during fruit development and ripening. In mature fruit, “ZAOHUA” and “96B41” accumulated high level of lycopene, “SANBAI” contained trace amounts of carotenoids. Through HPLC and dot blot hybridization, carotenoid content was analyzed and compared to the expression of carotenoid-related genes including Psy, Pds, Zds, CrtIso, Lcyb, Chyb, Nced1, Nced2, Nced3 during fruit development. All genes examined were expressed in all five watermelon varieties. In red and pink color varieties, the decrease of gene expression for Lcyb and Chyb at stage C (30 d after pollination) may be consistent with the high accumulation of lycopene and β-carotene. In the yellow variety, expression of the detected genes increased markedly with the onset of maturation, but little carotenoid accumulation was detected, which may be due to high level of carotenoid cleavage dioxygenases. Expression of all detected genes decreased rapidly in the white color variety upon fruit ripening, which may be attributed to a reduction in metabolic flux in the carotenoid pathway. These results imply the complex regulation of the carotenoid biosynthetic pathway in watermelon.  相似文献   

14.
The recent progress on bell pepper transformation through in planta approach is incredibly simple with high transformation efficiencies in indigenous varieties. This method produces chimeric primary transformants (T0) hence, a large number of T0 plants and an efficient high throughput screening strategy is necessary to be developed. In the present investigation, we have standardized a rapid and highly efficient method of screening putative bell pepper transformants. Bell pepper transformants harbouring gfp genes was developed using in planta approach and 1050 etiolated T1 seedlings were screened using fluorescent microscope to select GFP positive plants. The molecular analysis such as, gene specific PCRs, semiquantitative RT-PCR and Southern blots analysis corroborated the transgene integration in selected T1 transformants. Based on progressive selection strategy, the transformation efficiency was 27.4% in gfp screened plants. The fluorescence based screening is viable, rapid, requires minimal labour, expense, and expertise with less percent of non-transformant escapes; further, this method can be extended from bell pepper to other crops to identify putative transformants developed through in planta approach.  相似文献   

15.
Broomrapes (Orobanche spp) are holoparasitic weeds that cause devastating losses in many economically important crops. The branched broomrape (Orobanche ramosa) represents a real threat for many vegetable crops including tobacco, tomato and potato.  相似文献   

16.
《Scientia Horticulturae》2005,105(2):213-221
Young leaf samples were taken from susceptible and resistant pear varieties in June and August for 2 years in 2000 and 2001 and were analyzed for phenolic compounds by using thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC) after artificial inoculation with Erwinia amylovora. The distribution of spots in relation to phenolic compounds on TLC plates showed differences in resistant varieties compared to susceptible ones. The number of spots in resistant varieties was generally higher than the other group. Some spots were peculiar for distinguishing resistant and susceptible ones. Similarly, on HPLC dendograms, mean arbutin value was higher in the resistant group than the susceptibles both in 2000 and 2001. Additionally, arbutin content was found to be higher than chlorogenic acid content both in resistant and susceptible varieties.  相似文献   

17.
A review of apple canker caused by Neonectria ditissima is presented for Northwestern Europe with a focus on the Lower Elbe region (Northern Germany). Whereas conidia released by rainsplash are produced mainly from spring to autumn, the liberation of wind-borne ascospores peaks in autumn and/or early spring. Infection occurs via natural as well as pruning-induced wounds, some of which are present throughout the year. Autumnal leaf scars are the most frequent entry point for N. ditissima. Wounds on tree trunks, especially bark cracks in the crotch regions, are potentially even more serious because cankers on trunks and leader shoots commonly cause the total loss of a tree. Surface moisture is a prerequisite for leaf scar infections but possibly not for an entry through other wounds. Irrespective of the entry route, successful infection of a wound requires a mass inoculum of at least 50–100 conidia or ascospores. Infections of trees originating in nurseries may enter a state of latency from which they can break out up to 3 years after the trees have been explanted into the production orchard. Streaks of brown wood discolourations can be caused both by systemic colonisation of the xylem by N. ditissima and by winter frost damage. Apple varieties may show pronounced differences in their sensitivity to canker. For highly susceptible varieties, this disease can be a major production-limiting factor. Flower infections by N. ditissima commonly lead to a pre-harvest rot at the blossom end of the fruit, whereas infections of the growing fruit before harvest lead to a storage rot. Rigorous pruning is an essential canker control measure. Chemical control during the growing season is achieved by apple scab fungicides such as dithianone, captan or dodine. At leaf fall and in winter, copper fungicides are indispensible for controlling canker on highly susceptible varieties in Northern Germany.  相似文献   

18.
Buxus sinica var. parvifolia, a rare and endangered tree species in some semitropics alpine areas of China, plays an important role in the maintenance of the landscape and ecosystem. In this study, RAPD and ISSR markers were used to investigate the genetic diversity and structure of five natural populations and one tamed population of B. sinica var. parvifolia. 21 RAPD primers amplified 209 bands with 167 (79.90%) polymorphic and 21 ISSR primers amplified 518 bands with 467 (90.15%) polymorphic. The genetic diversity, estimated by Shannon’ index, was 0.4343 (by RAPDs) and 0.3661 (by ISSRs). Both RAPD and ISSR analyses revealed a high level of genetic diversity in natural populations of B. sinica var. parvifolia. Furthermore, analysis of molecular variance (AMOVA) was used to apportion the variation within and between populations. The proportion of variation attributable to within-population differences was very high (69.2% by RAPDs; 84.51% by ISSRs). Moderate differentiation was detected among populations using RAPDs (30.80%), while only a small amount of variation (15.49%) was detected among populations using ISSRs. We suggest that the present genetic structure is due to high levels of environmental variability and gene flow, which still need further study to confirm. Conservation measures are suggested, including in situ and ex situ strategies, based on the observed population genetic information.  相似文献   

19.
Mulberry is a perennial and economically important plant that has traditionally been used for feeding the silkworm. Evaluating genetic relationship is important for long-term improvement in mulberry yield, quality and resistance, and for germplasm conservation and identification. Population structure and genetic diversity of 8 mulberry populations from different ecotypes in China were analyzed by ISSR markers. Twelve ISSR primers generated a total of 83 amplification products, of which 50 were polymorphic, revealing 60.24% polymorphism among 66 mulberry local varieties, the mean PIC value was 0.1469. The total heterozygosity (HT), heterozygosity within population (HS), diversity between populations (DST) were 0.1600, 0.0851 and 0.0749, respectively. The coefficient of population differentiation (GST) was 0.4683, indicating that the variations among populations and those within populations contributed 46.8% and 53.2% to the total heterozygosity, respectively. The gene flow (Nm) was 0.5678, suggesting that genetic drift between populations can caused local genetic differentiation and therefore, population divergence. The mean genetic similarity coefficient was 0.8456, genetic similarity coefficient among 8 mulberry populations ranged from 0.8441 to 0.9640, indicating that genetic diversity of different populations existed variation. A dendrogram of all 66 local varieties of mulberry based on the genetic similarity using ISSR markers was generated by UPGMA cluster method. In the dendrogram, most varieties from the same ecotype clustered together.  相似文献   

20.
Somatic embryogenesis is the preferred method for cell-to-plant regeneration of grapevine. In this study, we tested the embryogenic capacity of anther-derived calli from 59 grape genotypes, representing a diverse group of Vitis vinifera and hybrid varieties, and hybrids and accessions of non-vinifera Vitis species. Most genotypes were tested on two types of media: MST1 medium, which contained plant growth regulators (PGRs) 2,4-dichlorophenoxyacetic acid (2,4-D) and thidiazuron (TDZ), and MSE medium, which contained 2,4-D and 6-benzylaminopurine (BAP). Twenty-four of the grape genotypes produced embryogenic callus on one or both of these media, eighteen of which have not been reported to form somatic embryos before. The results also suggested that the various PGR combinations are differentially effective at inducing somatic embryos in various classes of grape genotypes. For example, seven of the eight V. vinifera conv. occidentalis varieties brought forth somatic embryos on MSE medium, and three out of four American Vitis genotypes produced somatic embryos on MST1 medium. We could not observe any apparent association between frequency of callus formation and embryogenic capacity of the anthers.  相似文献   

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