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1.
A diallel cross amongst four contrasting white clover varieties was used to provide genetic information on those characters which affect the productivity of white clover-perennial ryegrass mixtures when grown under a cutting-only management regime. Generally speaking those characters recorded on the clover families and in mixtures exhibited highly significant additive and non-ad dative genetic effects, though for1 sortie characters the latter could not be ascribed solely to dominance effects. For two of the clover characters, stolon and leaf number, the genetic picture was radically altered in mixtures by the effects of inter-specific competition Pseudo-genetic effects were also detected for the grass characters, bur it was suggested that the two ryegrass varieties used here were exhibiting phenotypic plasticity. As a group the four intra-varietal crosses performed significantly better than the six intra-varietal crosses for all clover and mixture characters. Only one of the inter-varietal crosses had significantly positive specific combining ability effects for most characters and that was between the two long established varieties ‘S. 184’ and ‘S. 100’. The implications of these results for the breeding of white clover varieties for use in mixtures are briefly discussed. 相似文献
2.
白三叶基因工程改良研究进展 总被引：1，自引：1，他引：0
白三叶（Trifolium repens L.）作为优良牧草和地被植物具有重要的应用价值。但其耐盐碱、干旱能力差等原因致使应用受到广泛限制,转基因技术的快速发展为白三叶种质创新提供了有效技术手段,为开展白三叶分子育种奠定了基础。本文就近30年来有关白三叶组织培养、转化方法、转基因遗传改良方面的研究进展进行了综述,并对其应用进行了展望。 相似文献
3.
Prasert Kongkiatngam Marcia J. Waterway Bruce E. Coulman Marc G. Fortin 《Euphytica》1996,89(3):355-361
Summary The use of random amplified polymorphic DNA (RAPD) markers obtained from bulked samples was investigated for cultivar identification in red clover. Pooled samples were examined in order to minimize variation within cultivars. To determine the appropriate number of individuals to include in the bulked samples representing each cultivar, DNA samples from two, three, four, five, ten and twenty individuals were pooled. Twenty was found to be an appropriate number of red clover individuals per bulk in order to amplify only the DNA sequences shared among most individuals in each cultivar. Fourteen 10-mer primers were used to amplify genomic DNA from combined leaf samples of 15 red clover cultivars from European, Japanese and North American origins. A total of 79 amplified products, of which 55 were polymorphic, was obtained. Cultivar-specific bands were observed with 13 primers. The amplification patterns obtained from two primers could distinguish all 15 red clover cultivars. Rogers' genetic distances for all 105 pairwise comparisons were calculated to evaluate relationships among these cultivars. Cluster analysis based on these genetic distances separated these 15 cultivars into three groups, with two of the groups consisting of a single Japanese cultivar each, while the third group included cultivars from European, North American, and Japanese origins. 相似文献
4.
Summary An analysis of the effects of competition upon the survival of three morphologically distinct genotypes of perennial ryegrass (Lolium perenne) in monocultures and the corresponding binary mixtures (duocultures), indicated that significant differences occurred between them in respect both of the pressures which they exerted and in their capacity to respond to these pressures. Response depended in this experiment upon cutting regime. This dependency is used to explain the rapid elimination of one of the genotypes from most of its duocultures under an infrequent but not under a frequent cutting regime. The implications of these results for survival in mixed pastures and for the ingress of weeds into such pastures are discussed briefly. 相似文献
5.
白三叶种质资源主要数量性状的变异与相关性研究 总被引：1，自引：1，他引：0
为了探讨白三叶(Trifolium repens L.)种质资源农艺性状变异和相关性,揭示各种质材料的特征特性和种质资源群间的遗传关系,本研究对78份白三叶种质的12个主要数量性状的变异和相关性进行了分析。结果表明：这些种质材料存在着丰富的遗传多样性,各个数量性状间均呈正相关,植株高度与小叶长度、小叶宽度、小叶大小、叶柄长度呈显著正相关;小叶长度与小叶宽度、小叶大小呈极显著正相关,与叶柄长度、叶柄直径呈显著正相关;小叶宽度与小叶大小呈极显著正相关,与叶柄长度、花柄直径呈显著正相关;小叶大小与叶柄长度、叶柄直径、花柄直径呈显著正相关。该批种质材料能为各类白三叶育种和遗传研究提供较为丰富的亲本材料。 相似文献
6.
The use of bulked leaf samples from individual plants for amplified fragment length polymorphism (AFLP) analysis was evaluated
as a tool for assessment of genetic diversity in white clover (Trifolium repens L.). Bulking of leaf samples produced slightly simpler AFLP profiles compared to the combined profiles of individual plants
from the same cultivar. Approximately 90% of bands which were present in individual plants were present in bulked samples
of the same cultivar. The majority of those absent were rare bands, shared by less than 25% of individual plants. Replicate
bulk samples gave almost identical banding patterns, demonstrating the robustness of the bulked AFLP technique. Cluster analysis
of AFLP data derived from individual plants resulted in a phenogram similar to that produced from data derived from bulked
samples of the same plants. AFLP analysis of bulked samples detected significant amounts of genetic variability among 52 cultivars
and accessions with genetic similarity values ranging from 0.42 to 0.92. However, cluster analysis of AFLP data only partially
reflected the geographic origin of cultivars and accessions and was not congruent with cluster analysis based on variation
for morphophysiological characters. Bulked AFLP analysis provides a powerful tool for rapid assessment of genetic variability
in white clover and may also be used for cultivar identification.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
7.
R. M. M. S. Thilakarathna Y. A. Papadopoulos S. A. E. Fillmore B. Prithiviraj 《Journal of Agronomy and Crop Science》2012,198(4):295-303
Red clover cultivars, including diploid and tetraploid, are commonly used in legume‐based pasture mixtures. However, information on nodulation under different starter N regimens is limited. We hypothesized that there is genetic variability among different red clover cultivars for nodulation. A root hair deformation assay was conducted using three diploid (AC Christie, Tapani and CRS15) and three tetraploid (Tempus, CRS18 and CRS39) red clover cultivars by inoculating them with Rhizobium leguminosarum biovar trifolii. Nodulation and morphological characteristics of two selected red clover cultivars, AC Christie and Tempus, were determined under five starter N concentrations (0, 0.2, 0.4, 0.8 and 1.6 mg per plant). Inoculation with rhizobia increased root hair deformation with significant interaction across cultivars. Nodulation was delayed under high starter N concentrations, and genotypic differences were evident for days‐to‐nodule initiation. There was a positive quadratic response to starter N for AC Christie and a negative quadratic response for Tempus for nodulation. Tempus had more active nodules (92 %) than AC Christie (73 %). The genetic variability of red clover cultivars should be considered in N fixation studies and their response to availability of initial N. 相似文献
8.
T. Seresinhe U. A. Hartwig W. Kessler J. Nosberger 《Journal of Agronomy and Crop Science》1994,172(4):279-288
The aim of this study was to investigate whether symbiotic nitrogen fixation in white clover nodules limits nitrogen supply and hence clover growth by repeated defoliation at two cutting heights. Other possible factors governing symbiotic nitrogen fixation in the field were also elucidated. Using 15 N, a 2-year field experiment including white clover ( Trifolium repens L. cv. Ladino) and perennial ryegrass ( Loliumperenne L. cv. Bastion) in monocultures and in mixtures was conducted in Eschikon, Switzerland. The effect of two cutting heights (4 cm and 10 cm above ground level) on the performance of symbiotic nitrogen fixation of white clover in the different sward-types was investigated. After each harvest, the plots were fertilized with 3 g N m-2 (equivalent to 30 kg N ha-1 cut-1 or 210 kg N ha-1 year-1 ). In both years, white clover grown in a mixture with grass received a significantly higher percentage of nitrogen from symbiotic fixation compared with clover grown in monoculture. This phenomenon is attributed to the strong competitiveness of ryegrass in soil nitrogen uptake. Consequently, white clover in the clover-ryegrass mixture was more dependent on symbiotic nitrogen fixation than that grown in monoculture. The cutting height did not preferentially influence symbiotic nitrogen fixation, as opposed to the uptake of mineral nitrogen from the soil. From this finding it is suggested that symbiotic nitrogen fixation did not limit the supply of nitrogen to clover and hence its growth. It is proposed that symbiotic nitrogen fixation in white clover is regulated by the demand for nitrogen rather than by the availability of carbohydrate reserves in the stolons. Symbiotic nitrogen fixation should thus be looked upon as an integrated plant growth factor and not as an isolated phenomenon. 相似文献
9.
Red clover (Trifolium pratense L.) is one of the main forage species of temperate regions. Cultivars of red clover are heterogeneous which makes their genetic
analysis difficult. We applied RAPDs (Random Amplifed Polymorphic DNA) in order to assess the genetic relationship and levels
of genetic variability existing among a group of 16 elite red clover parents organised in four subsets of 4 parents each.
Out of 55 primers 21 provided reproducible results. A total of 135 reliable and polymorphic RAPD bands were detected which
were used to estimate genetic distances among pair-wise combinations of elite parents. Nei and Li's similarity values ranged
from 0.60 to 0.77, with a mean of 0.66, which reflects a rather high genetic variability among the genotypes evaluated. Lower
levels of genetic variability, as detected by polymorphic loci and mean heterogeneity values, were detected in a subset of
parents selected for resistance to the stem nematode. Cluster analyses resolved the different sets of parents in a manner
consistent with what is known from their breeding origins. An Analysis of Molecular Variance detected substantial levels of
variation within subsets of parents. RAPDs represent a valuable source of genetic information for red clover breeding programmes.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
10.
J. C. Simon A. Jacquet M. L. Decau E. Goulas F. Le Dily 《European Journal of Agronomy》2004,20(4):341-350
The influence of cutting frequency was studied on white clover (Trifolium repens L.) cultivars (giant-Aran and dwarf-Rivendel) during two experiments set up under field conditions. Clover morphological and biochemical characteristics were measured prior to regrowth in response to various cutting interval treatments (1, 2, 3, 6 and 8 weeks of regrowth between two successive defoliations). The morphology of the aerial parts of the plant was described through the residual leaf area (RLA), the number of total growing points (TGP), stolon length and stolon and root dry matter productions per unit of cultivated area, as well as stolon dry weight per unit length. C and N reserve status was assessed by starch and vegetative storage proteins (VSP) concentration and amount measurements. Cutting frequency largely influenced the different variables. RLA and TGP increased in response to frequent cuttings while all other morphological and biochemical parameters decreased, with the exception of the soluble protein concentrations and protein amounts. Nevertheless, a significant difference in morphology and C and N reserve accumulation was shown between the two clover cultivars. In spite of a few number of leaves and growing points, the giant cultivar Aran showed higher C and N reserves, compared with the dwarf type Rivendel. However, the genetic expression of these differences was tightly linked to the cutting frequency applied to the sward, and was at its maximum in response to the most frequent treatments. Subjected to severe cuttings, both genotypes showed an increase in RLA and TGP, the greater effect of the treatment was obtained with the dwarf-type Rivendel. Frequent defoliations strongly reduced organic reserves but the cutting-induced decreases observed in starch and VSP contents were similar for each cultivar. Overall results confirmed that the morphological development of clover, partly defined by genetic performance, should also be controlled by cutting frequency, and highlighted a tight relationship between morphogenesis, reserve accumulation and sward management. Results are also discussed in terms of the use of C and N reserve contents as a further characterisation of white clover cultivars. 相似文献
11.
Genetic variation within and between two cultivars of red clover (Trifolium pratense L.): Comparisons of morphological,isozyme, and RAPD markers 总被引：2，自引：0，他引：2
Summary Morphological, isozyme and random amplified polymorphic DNA (RAPD) markers were used to estimate genetic variation within and between cultivars of red clover (Trifolium pratense L.), an important temperate forage legume. Two cultivars of red clover, Essi from Europe and Ottawa from Canada, were evaluated. Six monogenic morphological characters were observed for 80 plants from each of these two cultivars. All six morphological loci were polymorphic in the cultivar Essi whereas only four loci were polymorphic in the cultivar Ottawa. Forty plants from each cultivar were assayed for isozyme markers. A total of 21 enzyme-coding loci with 43 alleles was detected using twelve enzyme systems. Thirteen and nine of these loci were polymorphic in Essi and Ottawa, respectively. The mean number of alleles per locus was 1.81 in Essi and 1.67 in Ottawa. Seventeen random 10-mer primers were screened for RAPD markers. Nine primers which gave clear and consistent amplified products were used to assay 20 individuals from each cultivar. Each primer gave from 7 to 20 amplified bands with an average of 14.8 bands per primer. One hundred and eight of 116 putative loci were polymorphic in Essi and 90 of 98 loci were polymorphic in Ottawa. High within-cultivar variation was observed in both cultivars using both isozyme and RAPD markers. This high polymorphism makes these markers useful for germplasm characterization and genetic studies in red clover. 相似文献
12.
I. Karsai Gy. Vida S. Petrovics E. Petcu B. Kobiljski S. Ivanovska Z. Bedő O. Veisz 《Euphytica》2012,186(1):139-151
The genetic diversity present in the breeding programs of southeast Europe was assessed in a set of 114 winter wheat (Triticum aestivum L.) cultivars using AFLP and SSR markers. The average genetic diversity characterised with the Jaccard’s distance coefficient was 0.605 with an interval of 0.053 and 0.889. The wheat cultivars originating from the four countries differed from each other in their clustering patterns, including the numbers of clusters and the most prevalent cluster, which was breeding program-specific. Hungarian and Romanian cultivars showed closer relationships, and Serbian and Macedonian cultivars grouped together more frequently. The phenotypic variability of the same cultivars was assessed under diverse ecological conditions of the four growing sites, measuring the disease resistance against two foliar diseases, and several agronomic traits. Of the phenotypic traits, powdery mildew and leaf rust responses showed significant associations with genetic diversity, whereas heading date, plant height and yield components did not. Through parallel assessment of genotypic and phenotypic diversity it was possible to separate winter wheat cultivars with similar genotype but diverse phenotype from those with similar phenotype but diverse genotype. This information will allow breeders to make informed decisions in selecting parents for new crosses. 相似文献
13.
山西省中部地区主栽小麦品种的标记分析 总被引：1，自引：0，他引：1
【研究目的】山西省中部地区是山西小麦生产的重要地区,了解该地区目前主栽小麦品种的基因组成特点,对于进一步选育新品种具有重要的指导作用。【方法】采用SDS-PAGE方法对10个山西省中部地区主栽小麦品种的高分子量谷蛋白亚基组成进行了分析,同时用黑麦1RS 上特有的醇溶蛋白标记对上述材料进行1BL/1RS易位检测,并进一步利用已经开发的小麦矮杆基因Rht8和PPO功能基因标记PPO18,分析了10个小麦品种的基因组成。【结果】结果表明,供试材料在编码HMW-GS 位点上具有较大的变异,其中晋太9923高分子量谷蛋白亚基评分为10分。携带有1BL/1RS易位的材料为4份,占供试材料的40.0%。Rht8基因的平均分布频率为70.0%,Ppo-A1b基因在参试品种中出现的频率达100%。 相似文献
14.
J. R. Caradus A. C. MacKay D. R. Woodfield J. van den Bosch S. Wewala 《Euphytica》1989,42(1-2):183-196
Summary Morphology, flowering, cyanogenesis and leaf markings of 109 white clover (Trifolium repens L.) cultivars, grown as spaced plants and in small plots, were measured. Principal component analysis and cluster analysis were used to compare cultivars. Cultivars were classified into four broad groups. The most important criteria for distinguishing between groups were leaf size, cyanogenesis and combinations of these. Group I, termed small, included small-leaved, prostrate cultivars; Group II, termed intermediate, included the majority of the cultivars which were characterised by medium sized leaves and relatively low cyanogenesis levels; Group III, termed large, included the large-leaved highly cyanogenic cultivars; and Group IV, termed ladino, included large-leaved acyanogenic cultivars. 相似文献
15.
White lupin (Lupinus albus) and narrow-leafed lupin (L. angustifolius) have special interest as high-protein feed crops but their cultivation is limited by low grain yields. This study aimed to
support breeding programs targeting Italy or other climatically variable south-European regions by investigating within-species
adaptation patterns across contrasting Italian environments. An additional aim was comparing species for yielding ability.
Eight narrow-leafed and six white lupin cultivars featuring different origin, phenological type (Mediterranean in both species;
winter in white lupin; spring in narrow-leafed lupin) and plant architecture (determinate or indeterminate in both species;
tall or dwarf in white lupin) were evaluated in a Mediterranean and a subcontinental-climate site under autumn and late-winter
sowing. Additive main effects and multiplicative interaction was preferable to joint regression for modeling yield responses.
In both species, cross-over GE interaction was observed (P < 0.05), autumn-sown Mediterranean and subcontinental environments were the most-contrasting for GE effects, and widely adapted
material included cultivars of Mediterranean phenological type with indeterminate growth. Material with determinate growth
was not among the best-yielding entries in any environment, whereas a dwarf winter-type white lupin entry was specifically
adapted to autumn-sown subcontinental environments. White lupin displayed larger genetic variation than narrow-leafed lupin
for phenology and other traits. Relationships of morphophysiological traits with grain yield were environment-specific and
were locally high for some white lupin traits (early flowering, long reproductive phase, high aerial biomass, low proportion
of pod wall). White lupin exhibited higher yielding ability than narrow-leafed lupin in all environments but the late-winter
sown Mediterranean one, when comparing locally top-yielding cultivars. 相似文献
16.
Summary Eighteen clones of white clover chosen at random were examined for their seed setting possibilities. Large differences in the size of the inflorescence and the rate of fertilization were found among the clones, so that breeding strains of white clover with better seed-setting seems possible. The number of ovules per floret seemed not very variable. 相似文献
17.
对不同年份育成的21个小麦品种（系）进行全基因组扫描,通过分析遗传距离和染色体区段/位点,明确其亲缘关系远近和遗传差异。分析可知,获得的2029个SNP基因位点在B基因组拥有较高的遗传多样性,其次是A和D基因组;在7个同源群中,第3和第6同源群呈现出较高的遗传多样性,而第1和第4同源群的遗传多样性较低;21条染色体中,3A、1B、6B染色体的遗传多样性较高,而1A、6A的遗传多样性偏低。对21份供试材料依据审定（育成）年份分析其群体的平均遗传距离,不同年份品种间的平均遗传距离先增大后减小,遗传多样性逐渐降低;21份供试材料间的遗传相似系数在0.69~0.99之间,大致可聚为4个类群,同一年份的品种一般聚在一起,与其系谱关系吻合。构建并分析供试材料的基因型图谱发现,00s、10s和现在育成的小麦品种（系）共有SNP和共有染色体区段分别主要在A、D和B基因组,对应已发表性状同不同年份育种目标吻合。同时发现21份供试材料均含有25个共同SNP位点,分布在1A、5A、6A、7A、2B、3B、6B、1D、2D、3D和7D染色体上,且每条染色体上分布的SNP位点数目均不相同,通过对应已发表性状进一步证实在品种（系）组配与选育过程中注重产量、株高、分蘖数、抽穗期、灌浆速率和抗病等性状的选择。以上研究结果可为今后小麦新品种组配和选育提供参考依据。 相似文献
18.
The aim of this work was to obtain mukifoiiare types of berseem clover with a great proportion of the leaf weight and increased plant weight. Thereby research an berseem clover over a 10 year period resulted in the transfer of the multicare gene(s) from a mutant plant of the monocut Fahl culrivar which possess such trait to the muiticut trifoliate culrivar Meskawi by crossing between them. A multicut multifoliate strain was developed after rune generations of selection.
The multsfoliate strain gave significantly higher dry forage yield than commercial cultivate Giza 10, Sakha 4, Giza 15, Helaly and Giza 6 by 22.1, 22.5, 24,8, 29.9 and 36.7%, respectively, in the first cut. On the other hand, the moltifoliate strain gave higher seasonal protein yield than cultivars, i.e. Helaly, Giza 10, and Giza 6 by 7.0,10.1, and 121 %, respectively.
The leaves/stems rario trait averaged over cuts was 18.3 % higher than for the five commercial trifoliate cultivars. Therefore, this multifoliate muiricut strain could be useful for forage especially before sowing cotton or other early summer crops. In addition to that, it could he used as a genetic marker for berseem breeders. 相似文献
The multsfoliate strain gave significantly higher dry forage yield than commercial cultivate Giza 10, Sakha 4, Giza 15, Helaly and Giza 6 by 22.1, 22.5, 24,8, 29.9 and 36.7%, respectively, in the first cut. On the other hand, the moltifoliate strain gave higher seasonal protein yield than cultivars, i.e. Helaly, Giza 10, and Giza 6 by 7.0,10.1, and 121 %, respectively.
The leaves/stems rario trait averaged over cuts was 18.3 % higher than for the five commercial trifoliate cultivars. Therefore, this multifoliate muiricut strain could be useful for forage especially before sowing cotton or other early summer crops. In addition to that, it could he used as a genetic marker for berseem breeders. 相似文献
19.
I. B. Norris 《Euphytica》1990,47(2):159-164
Summary The inheritance of the cold induction response in the UK cultivar of white clover Menna, was assessed in controlled environments.Only 50% of the population flowered without prior cold induction. The cold period increased the number of stolons which became reproductive.All families from the crosses between induction and non-induction requiring genotypes produced progeny lacking a cold requirement for flowering.Heritability estimates for the number of flowers per plant, reproductive buds per stolon and stolon number were high.The necessity of eliminating the cold induction requirement in potentially valuable white clover cultivars in relation to seed production at lower latitudes is discussed. 相似文献
20.
Summary When white clover plants were self-pollinated, 75% of a 143-plant population did not set seed. Plants which did set small numbers of seed probably did so as a result of pseudo-self-compatibility. One highly self-compatible plant was selected from the breeding materials. The S2 progeny of this plant was autogamous and genetically fixed for morphology and isozyme patterns. Genetic analyses of self-compatibility were conducted as far as the F3 progeny. It was concluded from these data that self-compatibility was inherited in a simple Mendelian way and that plants homozygous for self-compatibility were obtained. There was no correlation between presence or absence of self-compatibility and growth vigor. The possibility of application of self-compatible plants to recurrent selection procedures is outlined and the utilization of self-compatible plants in white clover breeding programs is discussed. 相似文献