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排序方式: 共有273条查询结果,搜索用时 578 毫秒
101.
Harvest management based on leaf stage of a tetraploid vs. a diploid cultivar of annual ryegrass 下载免费PDF全文
Leaf stage‐dependent defoliation is linked to the plant's physiological status and may be a more suitable criterion than time‐based intervals for harvesting forage grasses, but no reports of research with annual ryegrass (Lolium multiflorum Lam. var. westerwoldicum) were found. To address this, a 2‐year field study was carried out at Raymond, MS, on a Loring silt loam soil (fine‐silty, mixed, thermic Typic Fragiudalfs). Forage production, morphological characteristics and nutritive value responses to defoliation based on leaf stage (2, 3 and 4 leaves per tiller) and two residual stubble heights (RSH; 5 and 10 cm) of a tetraploid (“Maximus”) vs. a diploid (“Marshall”) cultivar of annual ryegrass were quantified. Forage harvested, in 2011, increased linearly as leaf stage increased from 7.3 to 8.8 Mg/ha, but during 2012 was least (7.0 Mg/ha) at 3‐leaf stage and similar at the other two leaf stages (7.6 Mg/ha). Tiller density was less for Maximus (1,191 tillers/m2) than for Marshall (1,383 tillers/m2). Leaf blade proportion decreased with increasing leaf stage and was greater by 9% for Maximus than for Marshall. Generally, forage nutritive value became less desirable with increasing leaf stage. There was a dichotomy in forage harvested and nutritive value responses, but maximum forage productivity was achieved when annual ryegrass was defoliated at the 4‐leaf stage interval. 相似文献
102.
四倍体和二倍体泥鳅及大鳞副泥鳅营养成分分析 总被引:2,自引:0,他引:2
利用常规肌肉营养分析方法测定了四倍体泥鳅、二倍体泥鳅和大鳞副泥鳅的肌肉营养成分。结果表明: 四倍体泥鳅、二倍体泥鳅和大鳞副泥鳅肌肉中蛋白质含量(鲜重) 分别为18. 68%、18. 69%和18. 20%; 脂肪含量分别为0. 796%、0. 106%和1. 203%; 水分含量分别为79. 81%、79. 52%和78. 40%; 灰分含量分别为0. 951%、11188%和1. 162%。3种泥鳅肌肉中都含有常见的17种氨基酸, 其中包括9种人体必需氨基酸。氨基酸总量(占鲜重)分别为17. 57%、18. 11%和17. 47%; 必需氨基酸总量分别为7. 84%、7. 98% 和7. 76%, 必需氨基酸的构成比例符合FAO /WHO 的标准。鲜味氨基酸含量分别为6. 98%、7. 33%和6. 95%。经比较分析, 四倍体泥鳅和二倍体泥鳅肌肉中蛋白质含量、17种氨基酸含量、氨基酸总量和必需氨基酸总量均很接近, 但都明显高于大鳞副泥鳅。 相似文献
103.
FU Bo LIU Di MA Hong GUO Zhen-hua WANG Liang LI Zhong-qiu PENG Fu-gang ZHANG Dong-jie LIU Zi-guang BAI Jing 《中国畜牧兽医》2017,44(1):148-154
The study was aimed to investigate the role of porcine oocyte nuclear factors during reprogramming. Somatic cell nuclei was introduced into intact MⅡ oocytes to establish tetraploid somatic cell nuclear transfer (SCNT) embryos containing both somatic nuclei and oocyte nuclei. And then the influence of the oocyte nucleus on tetraploid SCNT embryo development was examined by assessing characteristics including cleavage rate and blastocyst rate. The results showed that the cleavage rate of tetraploid SCNT embryos,diploid parthenogenetic embryos and haploid parthenogenetic embryos was extremely significantly higher than that of standard diploid SCNT embryos (P<0.01). The blastocyst rate and the total number of cells in tetraploid SCNT embryos were extremely significantly higher than that of standard diploid SCNT embryos (P<0.01).Overall,tetraploid SCNT embryos had a higher developmental competence than standard diploid SCNT embryos. In conclusion, the embryonic model was established in which a fetal fibroblast nucleus and an oocyte M Ⅱ plate coexist. Tetraploid SCNT represented a new research platform that was potentially useful for examining interactions between donor nuclei and oocyte nuclei. This platform should facilitate further understanding of the roles played by nuclear factors during reprogramming. 相似文献
104.
An investigation was carried out into the survival of two tetraploid varieties of perennial ryegrass ( Lolium perenne L.), sown in a mixture with a diploid and very intensively grazed for over five years.
Mixture M1 consisted of the late heading varieties Meltra and Vigor , and mixture M2 of the early heading varieties Merlinda and Melino.
The ploidy was determined by microscopic analysis.
The share of the tetraploid component decreased in both mixtures. The decrease was more pronounced in the early heading mixture. Information was also sought on the technique of sampling such swards. 相似文献
Mixture M1 consisted of the late heading varieties Meltra and Vigor , and mixture M2 of the early heading varieties Merlinda and Melino.
The ploidy was determined by microscopic analysis.
The share of the tetraploid component decreased in both mixtures. The decrease was more pronounced in the early heading mixture. Information was also sought on the technique of sampling such swards. 相似文献
105.
High density genetic map and quantitative trait loci(QTLs) associated with petal number and flower diameter identified in tetraploid rose 下载免费PDF全文
Peter M. BOURKE 《农业科学学报》2021,20(5):1287-1301
Rose is one of the most important ornamental and economic plants in the world. Modern rose cultivars are primarily tetraploid, and during meiosis, they may exhibit double reduction or preferential chromosome pairing. Therefore, the construction of a high density genetic map of tetraploid rose is both challenging and instructive. In this study, a tetraploid rose population was used to conduct a genetic analysis using genome sequencing. A total of 17 382 single nucleotide polymorphism(SNP) markers were selected from 2 308 042 detected SNPs. Combined with 440 previously developed simple sequence repeats(SSR) and amplified fragment length polymorphism(AFLP) markers, a marker dosage of 6 885 high quality markers was successfully assigned by GATK software in the tetraploid model. These markers were used in the construction of a high density genetic map, containing the expected seven linkage groups with 6 842 markers, a total map length of 1 158.9 c M, and an average inter-marker distance of 0.18 c M. Quantitative trait locus(QTL) analysis was subsequently performed to characterize the genetic architecture of petal number and flower diameter. One major QTL(qpnum-3-1) was detected for petal number in three consecutive years, which explained 20.18–22.11% of the variation in petal number. Four QTLs were detected for flower diameter; the main locus, qfdia-2-2, was identified in two consecutive years. Our results will benefit the molecular marker-assisted breeding of modern rose cultivars. In addition, this study provides a guide for the genetic and QTL analysis of autotetraploid plants using sequencing-based genotyping methods. 相似文献
106.
E. N. Sedov G. A. Sedysheva E. V. Ul’yanovskaya Z. M. Serova 《Russian Agricultural Sciences》2009,35(3):156-159
An agrobiological and cytoembryological assessment of eight apple tetraploid varieties and a number of tetraploid seedlings, the donors of diploid gametes, is given. A high breeding value of seedlings from hybridization at the polyploid level is noted. A brief economic and biological characterization of 13 new apple varieties of different ploidy obtained from intervalent crosses is given. 相似文献
107.
以2年生5种四倍体泡桐为材料,研究其光合作用、材积生长量、接干长度、比叶重( SLW)等指标间的差异。结果表明,5种四倍体泡桐叶片的净光合速率( Pn)、气孔导度( Gs)、蒸腾速率( Tr)、胞间CO2浓度( Ci)光合因子的日变化规律相同。9月份叶片的Pn、 Gs、 Tr、 Ci日变化为单峰曲线,四倍体豫杂一号泡桐( TF4)的最大净光合速率高于其余4个种。此外,四倍体毛泡桐( T4)的树高生长量和接干高增长量、 TF4的胸径生长量和比叶重增长量、四倍体南方泡桐( A4)的材积增长量最大。5种四倍体泡桐的树高、胸径、接干、材积的相关性表明,材积与胸径呈正相关关系,相关性显著;树高与比叶重呈正相关关系,但相关性不显著。 相似文献
108.
取四倍体刺槐3年生采穗圃中1年生硬枝和半木质化嫩枝枝条为试材,研究硬枝和嫩枝插条不定根发生过程中可溶性蛋白、可溶性糖、淀粉和植物总氮含量及C/N比值的变化规律,为四倍体刺槐扦插生根的化学调控提供参考依据。结果表明:(1)不定根形成过程中,对照插穗可溶性蛋白含量持续下降;经IBA处理的插穗可溶性蛋白含量先降低后升高,且经IBA处理的硬枝插穗可溶性蛋白含量显著高于对照。(2)插穗可溶性糖含量先升高后降低;经IBA处理的插穗可溶性糖含量明显高于对照,且可溶性糖含量达到高峰的时间较对照提前5 d。(3)经IBA处理的插穗淀粉含量下降的速度大于对照,且经IBA处理的硬枝插穗和对照之间差异水平显著。(4)植物总氮对四倍体刺槐扦插生根的影响作用较小。(5)四倍体刺槐扦插,插穗C/N比值越高,生根能力越强。 相似文献
109.
秋水仙素诱导杂交兰四倍体及倍性鉴定 总被引:4,自引:2,他引:2
以杂交兰F1代无菌苗(2n=2x=40)为供试材料,分别用浓度为0.02%、0.05%、0.10%和0.20%的秋水仙素对其根状茎处理24、48和72h,成功获得了四倍体植株。试验结果表明,以0.10%的秋水仙素处理48h诱导效果最佳,变异率为36%。根尖染色体压片表明,四倍体染色体数为2n=4x=80,二倍体对照为2n=2x=40。加倍后的植株较二倍体植株粗壮,叶片变厚,颜色变深,茎基部粗壮,颜色深,生长势变缓,根系变粗,根状茎增粗,可作为新材料加以利用。 相似文献
110.
S. Gowers 《Euphytica》1977,26(1):203-206
Summary Five lines of tetraploid turnips and their diploid progenitors were examined. Diallel crosses were made at each level of ploidy and trial results showed that in all cases the diploids outyielded their respective tetraploids for dry matter production. 相似文献