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Summary Gene pyramiding in Phaseolus vulgaris is being utilized to develop more effective resistance to the temperature-insensitive-necrosis-inducing (TINI) strains of Bean Common Mosaic Virus (BCMV) present in the USA. Our data indicate that contrary to previous work, the bc-3 gene is effective against these strains in the absence of the strain unspecific bc-u gene in genotypes possessing the I gene. The epistatic bc-3 gene interferes with traditional efforts to pyramid the other recessive resistance genes by masking their activity. Indirect selection based on markers linked to the other recessive resistance genes would likewise be ineffective without the ability to also select for the bc-u gene which is required for expression of the bc-2
2 gene in germplasm carrying the I gene. Because the most resistant genotype (I, bc-u, bc-I
2, bc-22, bc-3) can only be introduced into a wide range of germplasm through the use of molecular markers linked to the different resistance genes, the search for a marker linked to the strain unspecific bc-u gene should also be given priority. 相似文献
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In our previous study, RAPD (Random Amplified Polymorphic DNA) analysis revealed species-specific markers for three medicinal Echinacea species (Asteraceae): E. angustifolia DC., E. pallida (Nutt.) Nutt. and E. purpurea (L.) Moench. In the present work, we have converted a RAPD marker (750 bp) for E. purpurea into a SCAR (Sequence Characterized Amplified Region) marker. SCAR-PCR, in fact, revealed the expected amplicon (330 bp) only in E. purpurea and not in the other two species, giving further evidence for differences in medicinal Echinacea spp. genome and confirming a greater similarity between E. pallida and angustifolia. 相似文献
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AFLP分子标记在小麦种质资源研究中的应用 总被引:11,自引:1,他引:11
AFLP(扩增性片段长度多态性 )是一种新的DNA分子标记 ,近年来广泛应用于小麦种质资源遗传多样性研究、种质指纹图谱构建及遗传材料鉴定、小麦遗传连锁图谱的构建、目的基因的分子定位、分子标记辅助选择以及基因表达调控与克隆研究等方面。本文对AFLP在小麦种质资源研究中的应用进展及前景进行了综述 相似文献
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Bermudagrass (Cynodon ssp.) germplasm is genetically diverse and widely distributed in the world. The study was conducted to identify and assess the molecular variation and relationship among 24 cultivars developed in China, Australia and the USA. Sequence-Related Amplified Polymorphism (SRAP) was applied to cultivars identification in this study for the first time. Thirty of the 90 SRAP primer combinations generated a total of 274 clearly bands encompassing 249 (91%) polymorphic. Each bermudagrass cultivar has its unique binary code and can be distinguished from the others. Three distinct clusters were obtained by unweighted pair-group method with arithmetic averages based on the polymorphic markers. Coefficients of genetic distance among the genotypes ranged from 0.57 to 0.97. The results demonstrated that SRAP marker is a stable molecular marker technique for the identification of bermudagrass cultivars and their genetic relationships. 相似文献
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利用AFLP分子标记对46个水稻品种进行遗传多样性分析,继而研究分子标记遗传距离与按照NC设计获得的195个杂交组合的产量及特殊配合力的相关性,探讨预测杂种优势的可能性。结果表明:(1)通过UPGMA聚类分析(图3),可将供试材料分为16个类群,并把来源不明的品种(系)划分到相应类群中,从而对这些材料进行初步鉴定。可见,AFLP分子标记是检测类内品种间遗传差异的有效方法,为水稻品种(系)亲本选配提供理论依据。(2)分子标记遗传距离与杂种产量优势、F1产量、特殊配合力之间都呈显著正相关,相关系数介于0.3235-0.7713之间。但相关程度还不足以预测杂种优势。增效座位和减效座位以及使用与杂种优势有关的QTL连锁标记位点可能提高杂种优势的预测能力,但最终解决,将依赖于杂种优势遗传机理的研究。 相似文献
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用随机扩增多态性DNA(RAPD)技术对泰国产方斑东风螺养殖群体的遗传多样性进行检测,从100个随机引物中筛选出21个引物对方斑东风螺的DNA进行扩增,结果表明:21个引物共检测到222条清晰且重复性好的条带,每个引物可扩增出4~16条带,分子量在200~2200bp之间,其中多态位点为156个,占70.27%;群体的Shannon多样性指数为0.2818,Nei基因多样性指数为0.2491;个体间最大遗传距离为0.291,最小遗传距离为0.066。通过与其他贝类遗传多样性的研究结果比较,可初步判断泰国产方斑东风螺养殖群体的遗传多样性比较丰富。 相似文献
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Gerard Allan Amber Williams Pablo D. Rabinowicz Agnes P. Chan Jacques Ravel Paul Keim 《Genetic Resources and Crop Evolution》2008,55(3):365-378
Worldwide genetic diversity in 200 individuals comprising 41 castor bean accessions was assessed using amplified fragment
polymorphisms (AFLPs) and simple sequence repeats (SSRs). We found that, despite surveying five continents and 35 countries,
genetic diversity in castor bean germplasm is relatively low (overall H
e = 0.126 for AFLPs and 0.188 for SSRs) compared to estimates of genetic diversity in other plant species. Our data also show
no geographic structuring of genotypes across continents or countries within continents. An assessment of the congruence between
AFLP and SSRs indicates a low correlation (R
2 = 0.19) between the two data sets, but each marker class nonetheless shows similar patterns of low-genetic diversity and
a lack of geographic structure. Our data do suggest that SSRs yield a higher percentage of polymorphic loci, higher heterozyosity
and a greater range of genetic distances, and are therefore more informative than are AFLPs on a locus-by-locus basis. Based
on comparisons with numerous other plant species, we suggest that the lower genetic variation in this worldwide collection
may be due to one or more factors including: sampling strategies that have not captured the full extent of genetic variation
in the species; artifactual variation due to long-term germplasm storage and seed regeneration; or intense selection followed
by domestic cultivation of a limited number of castor bean genotypes, which are widely propagated for their horticultural
and agro-economic value. 相似文献
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利用AFLP分子标记构建杂种葱的遗传图谱 总被引:5,自引:0,他引:5
利用大葱与野葱杂交获得的F2分离群体,通过AFLP分子标记的遗传分析,构建了包含10个连锁群,228个遗传标记的杂种葱较高密度的连锁图谱,该图谱覆盖902.6cM,平均图距为3.95cM。 相似文献