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1.
白菜型油菜在中国的起源与进化   总被引:24,自引:0,他引:24  
以云南长角(甘蓝型油菜,B.napus)、青海牛尾梢(芥菜型油菜,B.juncea)、汕头芥蓝(B.alboglabra)和黑芥(B.nigra cy giebra)为参照品种,对不同地理来源的82份白菜型油菜(B.campestris L.)资源进行了形态学鉴定和RAPD分子标记分析。利用分子进化遗传分析软件(MEGA)构建白菜型油菜的系统发育树,以揭示白菜型油菜在我国的起源与进化。分析表明:北方小油菜(B.campestris var.oleifera)的起源早于南方油白菜(B.chinensis var.oleif-era);冬油菜(Winter type B.campestris var.oleifera)的起源早于春油菜(Spring type B.campestris var.oleifera);关中蔓菁是起源较早的北方小油菜。陕西可能是北方小油菜的起源地,后来逐渐分化出广泛种植于甘肃、青海等地的春油菜;南方油白菜可能起源于云南、贵州、四川、湖北等地。形态性状与分子标记相结合,可用于研究白菜型油菜的起源与进化。  相似文献
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Summary This paper shows that questions of an unexpected phylogenetic depth can be addressed by the study of mitochondrial DNA (mtDNA) sequences. For decades, it has been unclear whether coelacanth fishes or lungfishes are the closest living relatives of land vertebrates (Tetrapoda). Segments of mtDNA from a lungfish, the coelacanth, and a ray-finned fish were sequenced and compared to the published sequence of a frog mtDNA. A tree based on inferred amino acid replacements, silent transversions, and ribosomal RNA (rRNA) substitutions showed with statistical confidence that the lungfish mtDNA is more closely related to that of the frog than is the mtDNA of the coelacanth. This result appears to rule out the possibility that the coelacanth lineage gave rise to land vertebrates; hence, morphological characters that link the latter two groups are possibly due to convergent evolution or reversals and not to common descent. Besides supporting the theory that land vertebrates arose from an offshoot of the lineage leading to lungfishes, the molecular tree facilitates an evolutionary interpretation of the morphological differences among the living forms. It would appear that the common ancestor of lungfishes and tetrapods already possessed multiple morphological traits preadapting their locomotion, circulation, and respiration for life on land.  相似文献
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冬小麦不同基因型幼苗形态性状遗传力和抗旱性的研究   总被引:19,自引:1,他引:18  
用植物根系喷雾试验箱培养冬小麦茶淀红×MY9094、轮抗7号×山农215953的四个亲本及其两个杂种F2,研究两叶到六叶期幼苗形态性状的遗传力及幼苗形态性状与抗生的关系。  相似文献
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A core collection is a chosen subset of large germplasm collection that generally contains about 10% of the total accessions and represents the genetic variability of entire germplasm collection. The purpose of a core collection is to improve the use of genetic resources in crop improvement programs. In many crops the number of accessions contained in the genebank are several thousands, and a core subset consisting of 10% of total accessions would be an unwieldy proposition. In this article we have suggested a two-stage strategy to select a chickpea mini core subset consisting of only about 1% of the entire collection held in trust at ICRISAT’s genebank (16,991 accessions). This mini core subset still represents the diversity of the entire core collection. The first stage involves developing a representative core subset (about 10%) from the entire collection using all the available information on origin, geographical distribution, and characterization and evaluation data of accessions. The second stage involves evaluation of the core subset for various morphological, agronomic, and quality traits, and selecting a further subset of about 10% accessions from the core subset. At both stages standard clustering procedure was used to separate groups of similar accessions. A mini core subset consisting 211 accessions from 1,956 core subset accessions, using data on 22 morphological and agronomic traits, was selected. Newman- Keuls’ test for means, Levene’s test for variances, the chi-square test and Wilcoxon’s rank-sum non-parametric test for frequency distribution analysis for different traits indicated that the variation available in the core collection has been preserved in the mini core subset. The most important phenotypic correlations which may be under the control of coadapted gene complexes, were also preserved in the mini core. This mini core subset, due to its drastically reduced size, will prove to be a point of entry to proper exploitation of chickpea genetic resources. Received: 20 August 2000 / Accepted: 25 September 2000  相似文献
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玉米根系形态性状和空间分布对水分利用效率的调控   总被引:17,自引:0,他引:17       下载免费PDF全文
玉米根系形态性状(总根长、根系表面积和根系干物质重)与植物整体水分利用效率间具有显著或极显著的相关性,回归曲线趋势基本相同,均呈二次曲线关系,只是相关系数不同。说明从提高水分利用效率来说,根系需要维持适宜的大小。其中根长对水分利用效率的贡献是第一位的,而根系干物质重的贡献最小,根系表面积介于二者之间。从空间分布来说,玉米每层节根数、节根长度和直径在父母本和杂交种间也具有显著或极显著的差异。与中下层根量相比,母本与不抗旱的父本处于上层干土中的根系数量明显较多,且根系直径大,吸水困难。而杂交种在干旱条件下上层根重和数量维持不变,或略高于不抗旱品种,但中层和下层根系数量和长度明显高于不抗旱品种,且根系直径小于不抗旱品种,这样从多的有效根系数量和低的吸水阻力两方面保证了水分的吸收,从而使其产量和水分利用效率均最高,说明通过根系形态特性和空间分布的优化能够调节作物整体的水分利用效率。  相似文献
6.
大白菜部分形态性状的QTL定位与分析   总被引:13,自引:0,他引:13  
于拴仓  王永健  郑晓鹰 《遗传学报》2003,30(12):1153-1160
应用352个标记位点的大白菜AFLP和RAPD图谱和一套栽培品种间杂交获得的重组自交系群体,采用复合区间作图的方法对大白菜9个形态性状进行QTL定位及遗传效应研究。在14个连锁群上检测到50个QTL:其中控制株型的QTL有5个;控制株高的QTL有6个;控制开展度的QTL有5个;控制最大叶长的QTL有7个;控制最大叶宽的QTL有4个;控制叶形指数的QTL有6个;控制中肋长的QTL有7个;控制中肋宽的QTL有4个;控制抽苔的QTL有6个。另外,估算了单个QTL的遗传贡献率和加性效应。这将为大白菜品种改良中形态性状的分子标记辅助选择提供理论依据。  相似文献
7.
达翰尔族、鄂温克族、鄂伦春族13项形态学研究   总被引:13,自引:1,他引:12  
本文报道了内蒙古呼伦贝尔盟达翰尔族485例、鄂温克族322例、鄂伦春族100例的13项形态特征的调查结果。X^2检验结果显示,鄂温克族与鄂伦春族之间形态特征相差较远,而鄂温克族与达翰尔族之间比较相象。多数形态特征无性别差异;少数有性别差异的形态特征在3个民族中表现不一;没有一项形态特征在3个民族中均表现出有显著性别差异。13项形态特征绝大多数具族间差异。  相似文献
8.
QTL analysis of leaf morphology in tetraploid Gossypium (cotton)   总被引:12,自引:0,他引:12  
Molecular markers were used to map and characterize quantitative trait loci (QTLs) determining cotton leaf morphology and other traits, in 180 F2 plants from an interspecific cross between a Gossypium hirsutum genotype carrying four morphological mutants, and a wild-type Gossypium barbadense. The prominent effects of a single region of chromosome 15, presumably the classical ”Okra-leaf” locus, were modified by QTLs on several other chromosomes affecting leaf size and shape. For most traits, each parent contained some alleles with positive effects and others with negative effects, suggesting a large potential for adapting leaf size and shape to the needs of particular production regimes. Twenty one QTLs/loci were found for the morphological traits at LOD≥3.0 and P≤0.001, among which 14 (63.6%) mapped to D-subgenome chromosomes. Forty one more possible QTLs/loci were suggested with 2.0≤LOD<3.0 and 0.001<P≤0.01. Among all of the 62 possible QTLs (found at LOD≥2.0 and P≤0.01) for the 14 morphological traits in this study, 38 (61.3%) mapped to D-subgenome chromosomes. This reinforces the findings of several other studies in suggesting that the D-subgenome of tetraploid cotton has been subject to a relatively greater rate of evolution than the A-subgenome, subsequent to polyploid formation. Received: 26 April 1999 / Accepted: 30 July 1999  相似文献
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