共查询到19条相似文献，搜索用时 500 毫秒
1.
2n配子在植物育种和种质创新中利用的研究进展 总被引：8，自引：0，他引：8
2n配子在植物进化过程中起了重要作用,目前,自发、诱发2 n配子已在马铃薯、苜蓿、红三叶草、越桔等作物的育种实践中应用,并分别获得了良好的效果.本文综述了关于植物2n配子的主要研究方向和近期取得的研究结果;植物自发、诱发2 n配子在有性多倍化、利用种质资源、传递杂种优势、克服胚乳平衡数障碍、克服自交不亲合、马铃薯实生育种及其他领域应用的优越性和已取得的成果;国际国内通过轮回选择、2 n花粉机械分离、诱导基因突变及直接诱导2 n配子等方法提高2 n配子利用效率的研究进展;2 n配子育种的应用前景. 相似文献
2.
本文以反映国内外马铃薯2n配子研究利用动态的大量文献为基础,综述了马铃薯2n配子在物种上的分布和细胞遗传学基础,并着重阐述了马铃薯2n花粉的形成机制、类型及其遗传效应.对2n配子在马铃薯杂种优势利用、实生种子选育、传递主效显性基因的作用和综合转移野生种有利基因方面的利用价值作了详尽的论述,并分析了2n配子研究利用的发展趋势. 相似文献
3.
彩色马蹄莲2n配子育种技术初探 总被引：2，自引：0，他引：2
以彩色马蹄莲的栽培品种‘黒魔术’Black magic、‘火烈鸟’Flamingo为实验材料,研究彩色马蹄莲2n配子育种技术。选择刚从茎秆中抽出的幼小健壮小花,用0.15%的秋水仙素处理以诱导2n配子,将诱导的2n配子进行不同组合的杂交实验。结果表明：秋水仙素处理对彩色马蹄莲雄雌蕊发育有一定毒副作用,其中对雌蕊的损伤大于雄蕊;2n配子能在一定程度上克服杂交后代不育性;在相同条件下,经2n配子诱导处理的杂交种子与未处理的对照种子相比,种子萌发时间大幅度缩短（50天左右）,叶片变薄、变大、叶色变浅,有些杂交植株表现出不同程度的畸变。通过对杂交后代的细胞学鉴定表明：处理配子杂交后代中获得染色体数目为48（2n=3x=48）的三倍体植株。 相似文献
4.
六倍体普通小麦(Triticumaestivum L., AABBDD, 2n=42)由四倍体小麦(T. turgidum, AABB, 2n=28)与节节麦(Aegilops tauschii Cosson, DD, 2n=14)天然杂交,然后通过染色体自动加倍形成。加倍过程主要受四倍体小麦未减数配子基因控制,且不同四倍体小麦存在不同的遗传效应。本研究利用位于3B染色体上未减数配子基因QTug.sau-3B的连锁SSR标记Xgpw1146和高通量DArTseq分子标记,筛选出可能转入四倍体小麦未减数配子基因的人工合成小麦改良后代。在105份改良材料中检测出17份具有四倍体小麦的Xgpw1146等位位点,表明四倍体小麦的未减数配子基因可能转入了这17份材料。利用DArTseq高通量标记技术分析人工合成小麦SHW-L1的88份改良后代,发现含四倍体小麦Xgpw1146等位位点的材料均具有来自SHW-L1、且可能包含Xgpw1146的一个染色体区段,表明未减数配子基因临近区域以一个区段传递到改良后代。这些人工合成小麦改良材料在加倍单倍体育种中有重要的应用潜力。 相似文献
5.
利用能产生2n配子的二倍体杂种与四倍体普通栽培种(S.tuberosum L.)和四倍体新型栽培种(Neo—tuberosum)进行了2x-2x,4x-2x和2x-4x间的杂交,获得了18个杂交组合的4x杂种家系,将这些家系与其10个4x亲本品种(品系)及对照品种在同一地点进行了连续两年的比较试验。结果表明:4x杂种家系单株平均块茎产量比亲本两年分别高16％和19％;其中最好的6个杂种家系比较好的4个品种(品系)分别高20％和43％;杂种产量的优势主要表现在单株块茎数目的显著增多,但在块茎商品率方面则与4x亲本差异不显著,而且杂种块茎的表现还不如4x亲本及对照品种,这是由于具2n配子特性的2x亲本这些性状较差所致。试验结果还表明杂种的遗传背景愈复杂其杂种优势也愈强,进一步说明马铃薯的产量与遗传异质性(多样性)的强弱可能有明显关系,利用2n配子特性可获得较高的遗传异质性。 相似文献
6.
果树辐射诱变育种研究进展 总被引：11，自引：1，他引：10
继实生选种和杂交育种后,辐射诱变育种也成为创造果树新种质的一个有效途径。通过辐射诱变,大大提高了果树基因突变频率,而且可以产生小量突变,获得常规育种难以获得的新种质。开展果树辐射诱变育种几十年来,国内外已经创造出许多的具有优良生物学性状和经济性状的果树新种质,辐射材料、诱变剂和诱变方法不断得到补充和改良,短枝型变异、早熟变异、抗性变异、无籽变异等辐射效应的研究也在逐渐深入地开展起来。同时,笔者认为果树辐射诱变育种与常规杂交育种、果树离体培养相结合是其今后发展的方向,辐射诱变育种和单倍体育种相结合在农作物育种上有诸多成功的例子,为其在果树育种上的应用也提供了有益的借鉴。 相似文献
7.
抗白粉病基因Pm21来自小麦近缘种簇毛麦。小麦一簇毛麦小片段顶端易位系NAU418(T1AS·1AL-6VS)和小片段中间插入易位系NAU419(T4BS·4BL-6VS-4BL)携带Pm21,高抗白粉病,是小麦抗病育种新种质。为了对其育种利用提供依据,以NAU418和NAU419为亲本分别与来源于不同生态区的郑麦9023等12个小麦品种杂交,杂种F_1再分别与来源于不同生态区的农艺亲本进行正、反回交,研究两种易位染色体在不同小麦背景中的遗传稳定性及其通过雌雄配子的传递规律。DNA分子原位杂交结果表明,在杂种F_1花粉母细胞减数分裂中期Ⅰ(Pollen Mother Cell,PMC MI),两种易位染色体分别可以与对应的小麦染色体配对形成棒状二价体。正、反交结果分析表明,NAU418中的小片段顶端易位染色体T1AS·1AL-6VS通过雌配子和雄配子的传递率分别为8.00%~50.98%和7.89%~45.07%,NAU419中的小片段中间插入易位染色体T4BS·4BL-6VS-4BL通过雌配子和雄配子的传递率分别为29.17%~52.38%和7.69%~47.06%。表明2个易位系中的易位染色体都可以通过雌、雄配子传递,但是其通过雄配子的传递率均显著低于通过雌配子的传递率。 相似文献
8.
观赏植物原生质体研究和应用 总被引：1，自引：0，他引：1
长期以来,植物育种多以有性杂交的方法进行,但由于植物的生殖隔离,许多植物存在杂交不亲和性,限制了有性杂交的组合和范围。另外,多数植物雌雄配子(即性细胞)间遗传物质的交换,只限于核基因,雄配子细胞质基因不能遗传。所以人们一直在寻求更好的遗传物质的传递途径。自1960年英国植物生理学家Cocking首次用纤维素酶分离原生质体取得成功以来,人们成功地将原生质体应用于植物育种研究,运用该技术对观赏植物进行遗传改良取得了一定进展。 相似文献
9.
10.
11.
Summary From data available in the literature and supplemented by information from private tulip breeders, it appeared that triploid and tetraploid varieties raised in the past, resulted from crosses between diploid tulips and between diploids and tetraploids. This can only be explained by the occurrence of diploid gametes in diploid (2n=24) cultivars. This phenomenon which may affect both female and male gametes, appears to be specific for certain varieties. Consequences for practical breeding are discussed. 相似文献
12.
A total of 45 tetraploid-diploid (4x—2x) hybrid progenies were obtained by crossing each of ten diploid parents as males to each of five tetraploid parents. A relatively low degree of determination (R2) of both 4x and 2x parents on the performance of their 4x—2x hybrid progenies was found for all six traits studied. This implies that test crossing and subsequent progeny analysis is necessary before such parents can be used in a breeding program. Since marketable yield was found to have a higher predictability than total yield, it is the preferred yield trait to be measured. Diploids which produce 2n gametes via FDR usually give rise to 4x progenies with a greater amount of heterosis than similar progenies derived from diploids which produce 2n gametes via SDR, although such heterosis is not necessarily expressed in terms of marketable yield. 相似文献
13.
Colchicine induced polyploids have not directly contributed for crop improvement in the past. On the other hand, the so-called
natural polyploids, derived from the functioning of numerically unreduced(2n) gametes have been shown to be more relevant for crop improvement in many cases. Different types of cytological abnormalities
during meiosis can give rise to 2n gametes and the genetic composition of these gametes is variable. Depending on the type meiotic abnormalities, various types
of 2ngametes, such as first division restitution(FDR), second division restitution (SDR),indeterminate meiotic restitution (IMR)
and post meiotic restitution (PMR) gametes,among others, have been described in recent years. For the improvement of autopolyploids
such as potato, alfalfa,Vaccinium spp., and some of the fodder grasses, FDR gametes have been proved to be highly useful. However, the use of 2n gametes for the improvement of allopolyploid crops has received much less attention so far. Some of the investigations on
allopolyploids, derived from Festuca-Lolium, Alstroemeria and Lilium species hybrids, have revealed that 2ngametes can be most useful for the introgression of alien genes and chromosomes into cultivars. An important feature of using
sexual polyploidization in the case of allopolyploids is that introgression can be achieved through recombination due to genetic
crossing-over between alien chromosomes as well as addition of alien chromosomes, which is extremely difficult or impossible
to achieve in the case of colchicine induced allopolyploids. Because of the recent developments in the field of plant molecular
biology, methods have become available for the analysis of 2ngametes and sexual polyploid progenies more accurately and to develop systematic breeding approaches. The methods include
DNA in situ hybridization (GISH and FISH)and molecular mapping (AFLP, RFLP, RAPDs).In addition to providing basic information
on the genetic and genome composition of the polyploid progenies, these methods can be potentially useful for a more efficient
creation of desirable breeding material and cultivars.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
14.
Summary Sexual polyploidization via the action of 2n gametes (gametes with the sporophytic chromosome number) has been identified as the most important evolutionary mode of polyploidization among plant genera. This study was conducted to determine whether 2n gametes are present in the tetraploid level of the genus Avena (2n=4×=28) Twenty tetraploid Avena lines, representing four species and one interspecific hybrid, were screened for pollen grain size in order to differentiate between n and 2n pollen. Avena vaviloviana (Malz.) Mordv. line PI 412767 was observed to contain large pollen grains at a 1.0% frequency. Cytogenetic analyses of pollen mother cells of PI 412767 revealed cells with double the normal chromosome number (i.e., 56 chromosomes at metaphase I and anaphase I). The mode of chromosome doubling was found to be failure of cell wall formation during the last mitotic division that preceded meiosis. The resulting binucleate cells underwent normal meiotic divisions and formed pollen grains with 28 chromosomes. Based on the formation and function of 2n gametes, three models involving diploid and tetraploid oat lines are proposed to describe possible evolutionary pathways for hexaploid oats. If stable synthetic hexaploid oat lines could be developed by utilizing 2n gametes from diploid and tetraploid oat species through bilateral sexual polyploidization, the resulting hexaploids could be used in breeding programs for transferring genes from diploids and tetraploids to cultivated hexaploids. 相似文献
15.
The widespread occurrence of 2ngametes (i.e. gametes with the somatic chromosome number) in the Medicago sativa-coerulea-falcata complex supports the concept that gene flow from diploid to tetraploid species occurs continuously in nature and plays a
key role in alfalfa evolution. Breeders realized early that gene transfer between ploidy levels via 2n pollen and 2n eggs would have had potential use in cultivated alfalfa improvement. Cytological investigations provided insights into the
types of meiotic abnormalities responsible for the production of 2n gametes. Alterations were defined as genetically equivalent to first (FDR) or second division restitution(SDR) mechanisms.
For breeding purposes,data have proven that 2n gametes of the FDR type are more advantageous than those obtained by SDR for transferring parental heterozygosity and retaining
epistatic interactions. The use of diploid meiotic mutants that produce 2ngametes is now recognized as one of the most effective methods available for exploiting heterosis and introgressing wild germplasm
traits into cultivated tetraploid alfalfa via unilateral (USP) and bilateral sexual polyploidization (BSP) schemes. Both2n egg and 2n pollen producers could be used for direct gene transfer from wild diploid relatives into cultivated alfalfa by means of 2x-4x and4x-2x crosses. Although data have shown that forage yield improvement can be achieved when plants are sexually tetraploidized,
problems related to reduced plant fertility and seed production remain largely unexplained. Apomixis has the potential of
cloning plants through seed and thus provides a unique opportunity for developing superior tetraploid cultivars with permanently
fixed heterosis and epistatic effects. A main goal in alfalfa breeding could be the introduction of functional apomixis (i.e.
Apomeiosis and parthenogenesis) in cultivated alfalfa stocks. In the future, the efficiency of alfalfa breeding programs based
on the use of reproductive mutants could be improved by direct selection at the genotype level using RFLPs and PCR-based markers.
Suitable DNA markers and detailed linkage maps of alfalfa mutants should help to discover apomictic mutants and address basic
genetic issues such as the extent of genomicre combination in polyploid hybrids and the effect of sexual polyploidization
on heterosis. Molecular markers have recently been used in alfalfa for studying the inheritance of 2n gamete formation and identifying polymorphisms associated to genes involved in meiotic abnormalities. Molecular tagging of
2n egg and 2n pollen formation not only should explain the genetic control and regulation of these traits, but may also be an essential
step towards marker-assisted selection of 2n gamete producers and implementation of USP and BSP breeding schemes. Future perspectives include strategies for the map-based
cloning of genomic DNA markers,and screening of EST mini-libraries related to flowers at different developmental stages from
meiotic mutants and wild-type scan lead to the identification of mRNAs and thus of candidate genes that control 2n gamete formation in alfalfa.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
16.
Summary High level of heterozygosity is directly related to heterosis for yield in polysomic polyploids. Modern breeding schemes in potato (2n=4×=48) involve utilization of wild or cultivated 2 x relatives that provide a source of allelic diversity, and 2n gametes that transfer diversity to the 4 x level. Different levels of allelic diversity and different modes of 2 n egg formation were considered theoretically to determine their significance for the recovery of heterotic 4 x progeny from 2××4× crosses. The support from the experimental data is provided.Decline in parental allelic diversity in 2××4× crosses or 4××4× crosses resulted in significant yield reduction. The average level of homozygosity and loss of intra-locus interactions are equally adequate to predict the trend in yield changes in 4 x potatoes derived from parents of variable allelic diversity utilizing different modes of 2 n egg formation.The differences between the modes of 2 n gamete formation increase when the genetic diversity decreases. The more genetically diverse parents the less pronounced differences between 2 n gametes. Breeding of 4 x cultivars for polygenic traits where nonadditive effects are important should be oriented towards maximizing heterozygosity in terms of allelic diversity. Utilization of 2 n gametes to generate 4 x progeny following 2×–× or 2×–2× crosses upgrades the level of heterozygosity depending on diversity present in parents. 相似文献
17.
Summary The extent and pattern of polyploidy in the tuber-bearing Solanums varies among the many taxanomic series that have been identified in this subsection of Solanum. While several series appear to be entirely diploid, others exhibit a range of ploidy levels from 2x to 6x, and some contain only polyploid species.In many diploid, triploid and tetraploid species 2n gametes (gametes or gametophytes with the sporophytic chromosome number) have been detected. Both 2n eggs and 2n pollen occur. 2n gametes provide the opportunity for unilateral and bilateral sexual polyploidization. The genetic determination and consequences of sexual polyploidization strongly suggest that 2n gametes have been the major instrument in the polyploid evolution of the tuber-bearing Solanums. Somatic doubling of species and interspecific hybrids appears to be of very limited importance.New evidence for the occurrence of 2n eggs and 2n pollen in many species is reported, and data from the literature are added to illustrate the widespread distribution of 2n gametes throughout the subsection. A very high correlation is found between polyploidy and 2n gametes, and its significance is discussed. Proof is presented for the occurrence of alleles governing 2n pollen production in the cultivated tetraploids, providing additional evidence for the hypothesis that 2n gametes have been involved in their origin.Multiple unilateral and bilateral sexual polyploidizations are proposed for the origin of the cultivated tetraploids: this accounts for the large variability encountered in this group, which closely resembles that of the related diploids. Similar evolutionary pathways are hypothesized for the other polyploid complexes in the subsection.A scheme is proposed in which participation of both 2n and n gametes link together all ploidy levels in the tuber-bearing Solanums, thus overcoming the ploidy barriers and providing for gene flow throughout the sympatric species of the subsection.Paper No. 2093 from the Laboratory of Genetics. Research supported by the College of Agricultural and Life Sciences, a gift from Frito-Lay, Inc., and grants from NIH (GM 15422) and The International Potato Center. Plant materials, unpublished chromosome counts and technical help of IR-1 are gratefully acknowledged. 相似文献
18.
This is the first report on the production of numerically unreduced (2n) gametes in Actinidia species. Their occurrence was
apparent from direct observations of microporogenesis in 2x, 3x, 4x and 6x plants and was inferred from ploidy analysis of
progenies from 4x-2x and 2x-4x crosses. Both male and female plants were found to produce 2n gametes. 2n gamete producers
were detected only in interploidy crosses. The observed frequency of 2n gametes was either similar to or towards the lower
end of the ranges reported for other genera. The role of sexual polyploidization in the evolution of the genus is discussed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
19.
Bilateral sexual polyploidization in potatoes 总被引：5，自引：0，他引：5
Summary Bilateral sexual tetraploidization was achieved by intercrossing diploid Phureja × haploid Tuberosum hybrids. Both parents contribute gametes with the somatic number of chromosomes (diplogynoids and diplandroids). More than 100 tetraploid progeny appeared in nine 2x–2x families. The tetraploids are generally more vigorous and significantly outyield their diploid full-sibs. The superiority of the tetraploids is interpreted on the basis of the mode of diplandroid (2n pollen) formation by first meiotic division restitution (FDR). Heterozygosis, epistasis and genetic diversity, if present in the parental diploid genotype, are largely maintained in the 2n gametes formed by FDR. and syngamy brings about more opportunities for heterotic responses in conjunction with polyploidization. Differences in tuber yield among tetraploid clones within families were found to be statistically significant (P <0.05). Thus, unlike somatic chromosome doubling, which can merely increase chromosome numbers, or somatic hybridization, which could in addition bring about heterosis, sexual polyploidization is also associated with genetic variability. The degree of inbreeding and the genotypic structure in the population of newly arisen tetraploids is discussed. The relationship among asexual reproduction, preservation of favorable nonadditive genetic effects by FDR. restoration of sexuality, and polyploidization is explored. The possible evolutionary significance of these factors is emphasized. 相似文献