共查询到19条相似文献，搜索用时 140 毫秒
1.
高粱SSA-1无融合生殖特性及其遗传分析 总被引：3，自引：0，他引：3
采用去雄杂交鉴定、遗传分析，对高粱ＳＳＡ－１无融合生殖系的结实特性，无融合生殖频率及其遗传行为进行了鉴定分析。研究结果表明ＳＳＡ－１具有自主结实特性，其自主结实为１３．３－３２．７％。绳索产受两对隐性基因控制，无融合生殖频率为２５．５％－５２．２％，为的兼性无融合生殖类型。该系无杂交不孕性，无融合生殖表达不受授粉方式，父类型等因子的影响，是目前无融合生殖研究以及固定杂种优势的良好基因材料。 相似文献
2.
利用EMS化学诱变高粱无融合生殖系的研究 总被引：2，自引：2，他引：0
使用浓度为0.3%的甲基磺酸乙酯（EMS）处理高粱无融合生殖系1094和2083的种子。4叶期将其幼苗移栽至大田试验地。目的是为了研究EMS对2个高粱无融合生殖系的影响,并选择变异株创新种质。结果表明,经过EMS化学诱变处理后,2个高粱无融合生殖系都出现不同程度的变异。M0代田间鉴定得到了株高、穗长、育性及结实率等突变体。两年平均株高、穗长、育性的变异率分别是0.66%、1.03%和1.93%,结实率以30%~40%分布的突变株为最多。因此,该技术在育种实践和理论上具有重要意义。 相似文献
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本文报导的是冬小麦兼性无融合生殖系８７１１３１研究结果，ａｍ８７１１３１初次杂交时Ｆ１表现隐性性状，Ｆ２不分离，Ｆ３整齐一致，表现十分明显的无融合生殖特性，经过几年的组合再配，正、反交，广泛测交，双胚苗筛选，去雄套袋等，结果表明这一材料是兼性无融合生殖系。 相似文献
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通过对上万份材料的筛选、鉴定、转化、处理等，用上述方法获得Am92372、Am871131、Am87-6072三个兼性无融合生殖材料。 相似文献
7.
无融合生殖：它的证实及其在植物育种中的应用 总被引：1，自引：0，他引：1
无融合生殖是一种通过种子进行的无性繁殖方式,它为未来的作物优良品种选育提供了独特的机遇。在一些栽培物种及与其有关的近缘野生植物中,无融合生殖发生的频率较低。本文的目的在于帮助植物育种工作者和遗传学家认识无融合生殖并提出在植物改良中的可能利用方法。无融合生殖向主要作物上的转育可以不需要细胞质雄性不育系而进行纯杂种的培育和商品化生产,可省工节支。由于专性无融合生殖的杂种产生杂合而整齐一致的后代,因而提供了一个将杂合基因带进新的遗传型的有效方法。优良的专性无融合生殖的杂种可不必进行稳定性试验而直接进行产量比较。无融合生殖杂种的利用可以简化商品杂种的生产过程。几种无融合生殖的机制都是遗传控制的,因此植物育种计划中的遗传操作将是一个主要问题,诸如以下的现象都应该作为无融合生殖的特性而加以调查:(1)杂种F_1或开放授精的杂本后代的一致性:(2)杂交后代中的母性类型;(3)不稳定基因型的高结实率;(4)多胚或一胚多苗现象。 相似文献
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早在 30年代 ,Navasshion和 Karpechenko就讨论过无融合生殖 ;嗣后 ,一些研究者发现了牧草、高梁、玉米、小麦等的无融合生殖。 80年代开始 ,我国的科学家注意到水稻无融合生殖在杂种优势利用上有着重大意义 ,并通过远缘杂交方法获得了无融合材料 ,鉴于无融合研究的新进展。 80年代末 ,袁隆平教授在杂交水稻三个战略阶段中 ,提出利用无融合生殖是一系远缘杂种优势利用的最有效的途径和方法。但利用无融合生殖 ,首先必须筛选可资利用的无融合基因 ,研究无融合生殖基因的遗传行为 ,为育种实践作指导。笔者本文的目的就是利用见诸报导的有关资… 相似文献
9.
利用分子标记辅助选择聚合Pi-1和Pi-2基因改良两系不育系稻瘟病抗性 总被引：17，自引：2，他引：15
以含广谱稻瘟病抗性基因Pi-1和Pi-2的BL122为供体, 温敏核不育系GD-7S为受体, 通过杂交、回交和自交并结合分子标记辅助选择, 将Pi-1、Pi-2基因导入温敏核不育系GD-7S中, 获得5个携带两个抗性基因的纯合改良不育株系。利用34个广东代表性稻瘟病菌株接种鉴定, 5个改良株系的抗性频率为94.12%~97.06%, 而对照GD-7S抗性频率仅为17.65%; 自然病圃诱发鉴定5个改良株系的叶瘟和穗颈瘟均为0级, 表现高抗。经自然条件和人工气候箱育性鉴定, 改良株系与对照均为无或少花粉败育类型, 自交结实率为0, 说明不育起点温度与对照基本一致。统计分析表明, 除剑叶长和每株穗数外, 改良株系与对照在其他农艺性状方面均无显著差异。与恢复系L38杂交, 改良株系的杂种F1与对照的F1大多农艺性状无显著差异, 说明改良株系基本保持了GD-7S的农艺性状和配合力。 相似文献
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Camilo L. Quarin 《Euphytica》1986,35(2):515-522
Summary Changes in incidence of apomixis were determined at different intervals of the flowering period in a highly sexual diploid cytotype of Paspalum cromyorrhizon
Trin., a natural tetraploid cytotype of the same species, and in the triploid and tetraploid intraspecific hybrids that were produced by pollinating the 2x cytotype with pollen of the tetraploid. Reproductive behaviour was determined from observations of embryo sacs in mature ovules. Gametophytic apomixis in this species in characterized by aposporous embryo sacs which differ from normal sacs by their number, orientation inside the ovule, their dimensions and shape, and the absence of antipodal cells.The potential for apomictic reproduction increased in relation to the ploidy level, suggesting a gene dosage effect in the incidence of apomixis. In the three ploidy levels, the highest incidence of apomixis was observed when the plants reached the maximum number of flowering heads. These findings suggest that the same environmental conditions that favour flowering should also be responsible for increasing the incidence of apomixis. An additional experiment under controlled conditions indicated that the light regime should be one of the factors that govern the amount of apomictic reproduction. Thus, polyploidy and apomixis should be of special significance in the dispersion and evolution of this grass species. The 4x facultative apomictic cytotype is far more frequent in nature than the highly sexual 2x. Moreover, most of the seeds produced in a flowering season should arise asexually. So, apomixis rapidly increases the number of plants bearing the successful maternal genotype, and sexual reproduction becomes important in adverse environmental conditions. 相似文献
12.
J. G. Th. Hermsen 《Euphytica》1980,29(3):595-607
Summary Apomictic propagation in potato holds a great promise for the new technology of growing potatoes from botanical seeds in stead of tubers. It is explained that apomixis results from the combination of abnormal meiosis, abnormal fertilization and parthenogenesis.An ideal scheme is given for growing potatoes from true seeds. This scheme remains utopian when autonomous apomixis is not available. Autonomous apomixis occurs when the reduction division is lacking (no gene recombination, no reduction of chromosome number) and the resulting 2n egg cell develops parthenogenetically without fertilization of the central nucleus. The first best approach is pseudogamous apomixis, which differs from autonomous apomixis in the necessity of fertilization of the central nucleus. Second best is the parthenogenetic development of 2n eggs, since these have originated through an abnormal type of reduction division. This type is characterized by the lack of formation of a reduction cell wall and fusion of the two spindles at metaphase II of meiosis (first division restitution).Apomixis in the narrow sense, either pseudogamous or autonomous, is defined. It has not been found in potato species or species hybrids. On the basis of our knowledge about characteristic features of existing apomictic species, about genetics and evolution of apomixis and about the occurrence of particular elements of apomixis in potato the possibility of introducing apomixis into potato from existing elements is discussed along with methods to induce missing elements. Some tentative approaches are suggested which in the long run may lead to the detection of potato genotypes with apomictic propagation.Edited version of a paper presented at the 19th Planning Conference of the International Potato Center (CIP) in Manila, Philippines in September 1979 on production of potatoes from true seed. Published with the consent of CIP. 相似文献
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Summary Segregation patterns in progeny arrays of selfed plants, heterozygous for the Mdh 1 isozyme marker locus, were used in an attempt to confirm the presence of apomixis in the grain sorghum line R473. No evidence for obligate apomictic reproduction was obtained. However, our studies did not rule out the possibility of a low level of facultative apomixis in R473. 相似文献
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F. Pank F. Matzk U. Kästner W.D. Blüthner E. Foltys de Garcia A. Meister U. Ryschka G. Schumann 《Euphytica》2003,134(1):77-84
St. John's wort (Hypericum perforatumL.) is a medicinal crop plant that reproduces by apomixis. To study the reproductive diversity within the initial breeding
material, 656 plants from 92 accessions of the species were analysed by flow cytometric seed screening (FCSS) and compared
to 66 plants of cv. ‘Topaz’ as a control. Among plants from the 92 accessions, 16 were obligate sexuals, nine were obligate
apomicts and all remaining ones were facultative apomicts. Among controls, there were six obligate and 60 facultative apomicts.
Tests of reproductive pathways indicated that, in the investigated collection, all apomictic plants were tetraploid and all
sexual plants were diploid. A strategy for a cross breeding program in St. John's wort is illustrated by crossing one diploid
obligately sexual mother plant with six tetraploid facultative apomicts. All 91 F1 progeny obtained were triploid with 58% being obligate sexuals and 42%
facultative apomicts. To quantify the different routes of seed formation within facultatively apomictic individuals, the reproductive
pathways were reconstructed from about 30 single seeds from each of five tetraploid and two triploid plants using FCSS. The
frequency of seed formed by apomixis ranged from 54% to 67% among four tetraploid genotypes. One triploid and two tetraploids
formed 23% to 73% of the so-called BIII hybrids (fertilization of unreduced eggs) and one triploid was obligately sexual. The results show that while the mode of
reproduction in H. perforatum is highly variable, tetraploid obligate apomicts as well as diploid and triploid obligate sexuals can be selected as starting
material for breeding purposes.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
15.
Esteban Rios Kevin Kenworthy Ann Blount Kenneth Quesenberry Bryan Unruh John Erickson Fredy Altpeter Patricio Munoz 《Plant Breeding》2017,136(2):253-260
The development of a turf‐type bahiagrass could have a remarkable impact on the billion‐dollar turf industry in the south‐eastern United States. The goals of this study were to (i) select bahiagrass genotypes with improved turf attributes and (ii) determine the reproductive mode and seed fertility of selected genotypes. The population included mutants, wild types, hybrids and standard cultivars evaluated at two locations for two years. Morphological variation was observed and clonal repeatability (H2) ranged from 0.27 to 0.90. Flowering was extremely reduced in some mutants, which also exhibited dark green colour, finer texture and reduced canopy height. Cytoembryological observations revealed that diploids reproduced sexually and tetraploids by obligate or facultative apomixis. Genotypes with superior seed fertility were identified, while others were comparable to the standard cultivars. While mutant plants exhibited great morphological variation, the random mutations did not affect their reproductive mode, validating the use of mutagenesis in apomictic species. The high H2 indicated that selection for improved turf attributes could be successfully performed with the advantage of clonal seed propagation. 相似文献
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Summary An interspecific hybridization program designed to transfer gene(s) controlling apomixis from Pennisetum squamulatum Fresen. (2n=6x=54) to induced tetraploid (2n=4x=28) cultivated pearl millet, Pennisetum americanum (L.) Leeke resulted in four offtype plants, two with 27 chromosomes and two with 28 chromosomes. These plants were found among 217 spaced plants established from open-pollinated seed of an apomictic 21-chromosome polyhaploid (2n=21) plant derived from an apomictic interspecific hybrid (2n=41) between tetraploid pearl millet and Pennisetum squamulatum. It appeared that a 21- (or 20-) chromosome unreduced egg from the apomictic polyhaploid united with a 7-chromosome pearl millet (2n=2x=14) gamete to produce a 28- (or 27-) chromosome offspring. Meiotic chromosome behavior was irregular averaging from 3.60 to 4.05 bivalents per microsporocyte in the 27- and 28-chromosome hybrids. The 27- or 28-chromosome hybrids, like the 21-chromosome female parent, shed no pollen, but set from 1.8 to 28 seed per panicle when allowed to outcross with pearl millet. Progeny of the 28-chromosome hybrids were uniform and identical to their respective female parents, indicating that apomixis had been effectively transferred through the egg. In addition, a 56-chromosome plant resulting from chromosome doubling of a 28-chromosome hybrid was identified. Pollen was 68 per cent stainable and the plant averaged 2.3 selfed seeds per panicle. Chromosomes of the 56-chromosome plant paired as bivalents (x=10.67) or associated in multivalents. Three to nine chromosomes remained unpaired at metaphase I. Multiple four-nucleate embryo sacs indicated the 56-chromosome hybrid was an obligate apomict. The production of 27-, 28-, and 56-chromosome hybrid derivatives were the results of interspecific hybridization, haploidization, fertilization of unreduced apomictic eggs, and spontaneous chromosome doubling. These mechanisms resulted in new unique genome combinations between x=7 and x=9 Pennisetum species. 相似文献
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番茄ps-2雄性不育系01222的育性观察 总被引：1，自引：0，他引：1
对从保加利亚引入并选出的含有番茄ps - 2基因的雄性不育新品系 0 12 2 2进行了杂交制种试验。结果表明 ,该不育品系虽然会发生自交 ,但座果率极低 ,其中正常果率只占 2 9% ,其余均为僵果。通过开花后 1～ 3d人工去雄授粉和蕾期去雄杂交制种试验比较说明 ,即使 3d后的处理杂交种子纯度仍可达 99%以上 ,符合国际种子质量标准 ,但是杂交座果率、单果种子含量却随开花天数的增加而降低 ,以蕾期和开花后 1d处理最佳。表明该不育系是一个很有应用价值的新材料。 相似文献
18.
P. Kaushal D. R. Malaviya A. K. Roy Shalini Pathak A. Agrawal Ambica Khare S. A. Siddiqui 《Euphytica》2008,164(1):81-92
One hundred and sixty accessions representing global germplasm of guinea grass (Panicum maximum Jacq.), an important apomictic (aposporous) fodder crop, were subjected to study on reproductive diversity in apomictic seed
development utilizing ovule clearing and flow cytometric seed screen (FCSS). Single seed FCSS of selected 14 tetraploid and
five hexaploid lines demonstrated uncoupling between the three apomixis components, viz. apomeiosis, parthenogenesis and functional
endosperm development, in natural as well as experimental populations, though it differed across ploidy levels and genotypes.
Reconstruction of reproductive pathways yielded a total of eight different pathways of seed development, arising by uncoupling/recombination
between apomixis components. Amongst these, two pathways involving modifications in embryo-sac (ES) (presence of two polar
nuclei in aposporous ES that fuse prior to fertilization) and fertilization process (fusion of only one polar nucleus in a
sexual ES) have been reported for the first time. Some of the combinations, such as MI (haploids arising from parthenogenetic development of reduced egg cell), were found viable only in hexaploid background. Germplasm
lines with higher expression of individual components were also identified. These components (including autonomous endosperm
development) were also experimentally partitioned in hexaploid progenies (derived from a tetraploid parent viz. accession
IG 04-164) that showed segregation in their reproductive capacities, and are reported for the first time. Occurrence of several
apomixis recombinants (phenotypic) in guinea grass lines suggested their hybrid origin, favors a multigene model for apomixis,
with their penetrance affected by modifiers and epigenetic mechanisms, in contrast to earlier reports of single locus control.
Implications of partitioning components on apomixis research are discussed. 相似文献