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1.
Two cycles of recurrent selection were performed in maize with the use of matroclinous haploids. Two synthetic populations, SP and SA, were improved. Each cycle consisted of two stages: (1) isolation of haploids from the synthetic populations and (2) growth of the haploids, pollination with pollen from diploid plants, and selection. The selection was performed for ear size in haploid plants. The mean gain in productivity in the synthetic populations SP and SA the per cycle was 16.48 and 20.98%, respectively. It is suggested that the high value of this index is related to the fact that haploid plants reveal useful genes with additive and epistatic effects. Natural selection may have played a part, too. The combination of artificial and natural selection in haploids resulted in a considerable gain in productivity in the synthetic populations to be improved. 相似文献
2.
In vivo haploid induction in maize 总被引:8,自引:0,他引:8
Eder J Chalyk S 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2002,104(4):703-708
Two haploid-inducing lines, MHI and M741H, were used for the production of maternal haploids. Haploids were obtained from
all maternal genotypes involved in the experiment, including dent, flint and flint×dent maize. The maternal genotype had a
significant influence on the frequency of haploids obtained. The frequency ranged from 2.7% to 8.0%. For chromosome-doubling
seedlings were treated with colchicine solution, and 49.4% of the haploid plants produced fertile pollen, 39.0% could be selfed
and 27.3% produced seeds after selfing. Synthetic populations, improved by haploid sib recurrent selection, were tested in
a field trial. The results show that the utilization of maternal haploid plants has great potential for maize breeding and
maize genetics.
Received: 14 May 2001 / Accepted: 3 August 2001 相似文献
3.
Jean-Nicolas Jasmin Marcus M. Dillon Clifford Zeyl 《Proceedings. Biological sciences / The Royal Society》2012,279(1746):4382-4388
The trade-off between growth rate and yield can limit population productivity. Here we tested for this life-history trade-off in replicate haploid and diploid populations of Saccharomyces cerevisiae propagated in glucose-limited medium in batch cultures for 5000 generations. The yield of single clones isolated from the haploid lineages, measured as both optical and population density at the end of a growth cycle, declined during selection and was negatively correlated with growth rate. Initially, diploid populations did not pay this cost of adaptation but haploidized after about 1000–3000 generations of selection, and this ploidy transition was associated with a decline in yield caused by reduced cell size. These results demonstrate the experimental evolution of a trade-off between growth rate and yield, caused by antagonistic pleiotropy, during adaptation in haploids and after an adaptive transition from diploidy to haploidy. 相似文献
4.
P. Lashermes A. Gaillard M. Beckert 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1988,76(4):570-572
Summary Experiments were conducted to investigate whether selection occurs during the processes involved in the production of doubled haploids. Haploid plants produced from two hybrids, each heterozygous for isozyme markers, were subjected to genetic analysis. The distributions of doubled haploid lines and pedigree lines derived from the hybrid C123 x Oh7 were compared with regard to agronomic character. The results suggest that the populations of haploid plants obtained by in vivo gynogenesis represent a random gametic array. Thus, in order to introduce haploid plants into breeding programmes in maize, maternal haploidy seems to be a very attractive method. 相似文献
5.
Hans D. Daetwyler Matthew J. Hayden German C. Spangenberg Ben J. Hayes 《Genetics》2015,200(4):1341-1348
Doubled haploids are routinely created and phenotypically selected in plant breeding programs to accelerate the breeding cycle. Genomic selection, which makes use of both phenotypes and genotypes, has been shown to further improve genetic gain through prediction of performance before or without phenotypic characterization of novel germplasm. Additional opportunities exist to combine genomic prediction methods with the creation of doubled haploids. Here we propose an extension to genomic selection, optimal haploid value (OHV) selection, which predicts the best doubled haploid that can be produced from a segregating plant. This method focuses selection on the haplotype and optimizes the breeding program toward its end goal of generating an elite fixed line. We rigorously tested OHV selection breeding programs, using computer simulation, and show that it results in up to 0.6 standard deviations more genetic gain than genomic selection. At the same time, OHV selection preserved a substantially greater amount of genetic diversity in the population than genomic selection, which is important to achieve long-term genetic gain in breeding populations. 相似文献
6.
Dr. J. Vagera Dr. F. J. Novák Dr. B. Vyskot 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1976,47(3):109-114
Summary The theoretically expected and experimentally observed phenotypic ratios have been compared in populations of haploids derived from chlorophyll mutants of Nicotiana tabacum L. with a known genotypic constitution. The frequencies of mutant genotypes were significantly lower than the expected values, proving the existence of selection in a system of haploid embryoids developing in the anther.The anthers from M1 plants of a diploidized Nicotiana tabacum haploid cv. Samsun, treated with various concentrations of N-nitroso-N-methylurea and n-butylmethane sulphonate, were cultivated in vitro. The number of anthers which gave rise to haploids (embryogenic anthers) was stimulated by lower concentrations of both the mutagens. The stimulation at the level of M1 sporophyte is explained by internal genetic heterogeneity induced by adequate mutagen concentration. The average number of haploids per embryogenic anther decreased in all the treatments. The frequency of haploid plants of the mutant phenotypes increased with increasing mutagen concentration. 相似文献
7.
Anthers of Nicotiana tabacum cultivar Wisconsin 38 were treated with the mutagen ethyl methane sulfonate and cultured to obtain populations of haploid plants of high genetic variability. The selection of these populations by their photosynthetic efficiency was carried out in a hydroponic culture chamber with a CO2 atmosphere concentration close to the compensation point. Plants that survived 45 days of treatment were grown in pots in a greenhouse and their performance was compared to a population of unselected haploids. The growth characteristics, net photosynthesis, and chlorophyll content were measured and the haploid character verified. Selected plants were propagated by in vitro culture of buds and then diploidized to obtain seeds. Growth and other characteristics of the plants obtained were compared with those of the parental variety (Wisconsin 38) in a field assay. Growth, dry weight, leaf area, and net photosynthesis of selected plants were higher than in control plants. 相似文献
8.
We tested the hypothesis that the time course of the evolution of antifungal drug resistance depends on the ploidy of the fungus. The experiments were designed to measure the initial response to the selection imposed by the antifungal drug fluconazole up to and including the fixation of the first resistance mutation in populations of Saccharomyces cerevisiae. Under conditions of low drug concentration, mutations in the genes PDR1 and PDR3, which regulate the ABC transporters implicated in resistance to fluconazole, are favored. In this environment, diploid populations of defined size consistently became fixed for a resistance mutation sooner than haploid populations. Experiments manipulating population sizes showed that this advantage of diploids was due to increased mutation availability relative to that of haploids; in effect, diploids have twice the number of mutational targets as haploids and hence have a reduced waiting time for mutations to occur. Under conditions of high drug concentration, recessive mutations in ERG3, which result in resistance through altered sterol synthesis, are favored. In this environment, haploids consistently achieved resistance much sooner than diploids. When 29 haploid and 29 diploid populations were evolved for 100 generations in low drug concentration, the mutations fixed in diploid populations were all dominant, while the mutations fixed in haploid populations were either recessive (16 populations) or dominant (13 populations). Further, the spectrum of the 53 nonsynonymous mutations identified at the sequence level was different between haploids and diploids. These results fit existing theory on the relative abilities of haploids and diploids to adapt and suggest that the ploidy of the fungal pathogen has a strong impact on the evolution of fluconazole resistance. 相似文献
9.
Summary Wheat (Triticum aestivum L.) haploids and doubled haploids have been used in breeding programs and genetic studies. Wheat haploids and doubled haploids
via anther culture are usually produced by a multiple step culture procedure. We improved a wheat haploid and doubled haploid
production system via anther culture in which plants are produced from microspore-derived embryos using one medium and one
culture environment. In the improved protocol, tillers of donor plants were pretreated at 4°C for 1–2 wk before anthers were
plated on a modified 85D12 basal medium with phenylacetic acid (PAA) and zeatin and cultured at 30°C with a 12-h daylength
(43 μEs−1m−2) in an incubator. Microspore-derived embryos developed in 2–3 wk and the plants were produced 3–4 wk after anther plating.
In the improved system, as much as 53% of the anthers of Pavon 76 were responsive with multiple embryos. For plant regeneration,
as many as 22 green and 25 albino plants were produced from 100 anthers. Sixty-five green plants were grown to maturity and
32 (49%) plants were fertile and produced seeds (indicating spontaneous chromosome doubling) while 33 plants did not produce
seed. Of five Nebraska breeding lines tested using the protocol, NE96675 was very responsive and the other lines less so,
indicating that the protocol is genotype-dependent. 相似文献
10.
标题双胚苗水稻中单倍体和二倍体不同器官的cDNA- AFLP分析 总被引:1,自引:0,他引:1
SARII-628是四川农业大学水稻研究所的一个双胚苗自然群体, 每年都能定期分离出单倍体与二倍体(n:2n)。文章对单倍体和对应的二倍体进行了cDNA-AFLP分析。合成了3个单倍体和1个二倍体的根、茎、穗和叶的cDNA, 用EcoR I/ Msp I酶切组合, 通过cDNA-AFLP技术统计这16个样本的表达差异。共选用30对引物, 在633条扩增位点上筛选出49个有差异表达的序列。结果:(1)单倍化后cDNA-AFLP总体水平虽然在各单株间略有差异但变化不大, 表达变化的位点所占比例平均为5.14%, 高于二倍体的3.93%; (2)根据样本在根、茎、穗和叶中表达出带的有无, 在扩增出的14种带型中, 有4种只出现在单倍体中, 其对应位点的表达具有单倍体的特异性; (3)对这3个单倍体在不同器官的激活和沉默位点进行汇总, 发现在根和穗中, 发生沉默的位点多于激活的位点数, 而在茎和叶中的结果正好与之相反, 但是在单倍体的所有器官中发生激活变化的位点多于沉默变化的位点; (4)对不同器官中的发生表达变化(激活+沉默)位点分析, 发现根中的变化位点最多, 在穗中的变化最少, 说明位点的表达变化具有器官特异性。 相似文献
11.
Ricca M Beecher FW Boles SB Temsch E Greilhuber J Karlin EF Shaw AJ 《American journal of botany》2008,95(12):1606-1620
Allopolyploid speciation is likely the predominant mode of sympatric speciation in plants. The Sphagnum subsecundum complex includes six species in North America. Three have haploid gametophytes, and three are thought to have diploid gametophytes. Microsatellite analyses indicated that some plants of S. inundatum and S. lescurii are heterozygous at most loci, but others have only one allele at each locus. Flow cytometry and Feulgen staining showed that heterozygous plants have twice the genome size as plants with one allele per locus; thus, microsatellite patterns can be used to survey the distribution and abundance of haploid and diploid gametophytes. Microsatellite analyses also revealed that S. carolinianum is consistently diploid, but S. lescurii and S. inundatum include both haploid and diploid populations. The frequency of diploid plants in S. lescurii increases with latitude. In an analysis of one population of S. lescurii, both cytotypes co-occurred but were genetically differentiated with no evidence of interbreeding. The degree of genetic differentiation showed that the diploids were not derived from simple genome duplication of the local haploids. Heterozygosity appears to be fixed or nearly so in diploids, strongly suggesting that although morphologically indistinguishable from the haploids, they are derived by allopolyploidy. 相似文献
12.
Efficient production of doubled haploid plants through colchicine treatment of anther-derived maize callus 总被引:3,自引:0,他引:3
Y. Wan J. F. Petolino J. M. Widholm 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1989,77(6):889-892
Summary A chromosome doubling technique, involving colchicine treatment of an embryogenic, haploid callus line of maize (Zea mays L., derived through anther culture), was evaluated. Two colchicine levels (0.025% and 0.05%) and three treatment durations (24, 48, and 72 h) were used and compared to untreated controls. Chromosome counts and seed recovery from regenerated plants were determined. No doubled haploid plants were regenerated from calli without colchicine treatment. After treatment with colchicine for 24 h, the callus tissue regenerated about 50% doubled haploid plants. All of the plants regenerated from the calli treated with colchicine for 72 h were doubled haploids, except for a few tetraploid plants. No significant difference in chromosome doubling was observed between the two colchicine levels. Most of the doubled haploid plants produced viable pollen and a total of 107 of 136 doubled haploid plants produced from 1 to 256 seeds. Less extensive studies with two other genotypes gave similar results. These results demonstrate that colchicine treatment of haploid callus tissue can be a very effective and relatively easy method of obtaining a high frequency of doubled haploid plants through anther culture. 相似文献
13.
Rex Bernardo 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2009,119(2):255-262
Maize (Zea mays L.) doubled haploid lines are typically produced from F1 plants. Studies have suggested that the low frequency of recombinants in doubled haploids may reduce the response to selection.
My objective was to determine if, for sustaining long-term response, doubled haploids should be induced in F1 or F2 plants during maize inbred development. In simulation experiments, I examined the response to multiple cycles of testcross
selection among doubled haploid lines derived from F1 plants (denoted by DH), doubled haploid lines derived from F2 plants (DHF2), and recombinant inbred (RI) lines derived by single-seed descent. For a trait controlled by 100 or more quantitative trait
loci (QTL), the cumulative responses to selection were up to 4–6% larger among DHF2 lines than among DH lines. The cumulative responses were up to 5–8% larger among RI lines than among DH lines. The QTL become
unlinked as the number of QTL in a finite genome decreases, and the responses among RI, DH, and DHF2 lines were equal or nearly equal when only 20 QTL controlled the trait. Metabolic-flux epistasis reduced the differences
in the response among RI, DH, and DHF2 lines. Overall, the results indicated that doubled haploids should be induced from F2 plants rather than from F1 plants. If year-round nurseries are used and new F1 crosses for inbred development are initially created on a speculative basis, the development of doubled haploids from F2 rather than F1 plants should not cause a delay in inbred development. 相似文献
14.
Katarzyna Niemirowicz-Szczytt 《Acta Physiologiae Plantarum》1997,19(2):155-167
The utility of haploids and DH lines for breeding programmes and basic research is discussed here. High effectiveness of haploid
induction from random responding gametes and from valuable donor plants is not sufficient to ensure success in breeding. DH
lines often appeared inferior to conventionally obtained inbred lines. One of the causes may be a very high level of homozygosity,
in this paper referred to as excessive homozygosity. Besides, colchicine treatment as well as gametoclonal and somaclonal
variation could have a negative effect on the agronomic performance of DH plants. Lack of natural selection in the first stages
of haploid development is another important factor, negatively influencing haploid utility.
On the other hand, there is a wide range of possibilities of using haploids as model plants for basic research. Among different
applications, including mapping, genetic analysis, mutations, transformation, somatic hybridisation, biochemical and physiological
studies, artificial seed production and germplasm storage, the first seems to be explored most effectively and give promising
results. 相似文献
15.
The objective of this work was to produce doubled haploid plants from durum wheat through the induction of androgenesis. A
microspore culture technique was developed and used to produce fertile doubled haploid plants of agronomic interest. Five
cultivars, one selected line, plus a collection of 20 F1 crosses between different genotypes of high breeding value were used. Studies on several factors such as pre-treatments and
media components were carried out in order to develop a protocol to regenerate green haploid plantlets. Anthers were pre-treated
in 0.7 M mannitol. Microspores, from anther maceration, were plated on a C17 induction culture medium with ovary co-culture. The optimum regeneration medium J25–8 was used. From 35 microspore isolations,
407 green plantlets were obtained. With this technique mature embryos were obtained. Green plants were regenerated from all
genotypes used and approximately 67% of them were spontaneously doubled haploids. Some haploids and a very few polyploids
plants were obtained. From the 407 plants, 275 were completely fertile and gave enough seeds to be assayed in the field. This
protocol could be used complementary to or instead of the intergeneric crossing with maize as an economically feasible method
to obtain doubled haploids from most durum wheat genotypes. 相似文献
16.
Sarah Perin Otto Jane Claire Marks 《Biological journal of the Linnean Society. Linnean Society of London》1996,57(3):197-218
According to the 'masking hypothesis', diploids gain an immediate fitness advantage over haploids because diploids, with two copies of every gene, are better able to survive the effects of deleterious recessive mutations. Masking in diploids is, however, a double-edged sword: it allows mutations to persist over tine. In contrast, deleterious mutations are revealed in haploid individuals and are more rapidly eliminated by selection, creating genetic associations that are favourable to haploidy. We model various mating schemes and show that assortative mating, selfing, and apomixis maintain the genetic associations that favour haploidy. These results suggest that a correlation should exist between mating system and ploidy level, with outcrossing favouring diploid life cycles and inbreeding or asexual reproduction favouring haploid life cycles. This prediction can be tested in groups, such as the Chlorophyta, with extensive variation both in life cycle and in reproductive system. Confirming or rejecting this prediction in natural populations would constitute the first empirical test of the masking hypothesis as a force shaping the evolution of life cycles. 相似文献
17.
Stable differences have been found between haploid and diploid Mikado tomato plants with respect to quantitative characteristics of their vegetative and generative organs, whereas these plants were phenotypically similar with respect to qualitative characteristics, such as the bush habitus and the shapes of leaves, flowers, and fruit. A simple indirect method based on counting the chloroplasts in guard cells has been suggested to diagnose haploids. Analysis of meiosis during microspore formation in haploids has revealed considerable anomalies leading to heterogeneity and a high sterility rate of pollen, which has been confirmed by differences in DNA content. The data obtained suggest that formation of fertile gametes is accounted for by the absence of reduction division. It has been hypothesized that meiosis in haploids induces the genotypic variation that is subject to selection. 相似文献
18.
Jin-Feng Chen Li Cui Ahmed Abbas Malik Kere George Mbira 《Plant Cell, Tissue and Organ Culture》2011,104(3):311-319
Haploids and doubled haploids are very important in plant breeding, enabling the time needed to produce homozygous lines to
be shortened compared with conventional breeding. In the present review, emphasis is given to haploid induction through unfertilized
ovule/ovary culture. Attention is given to induction of haploid plants from female gametophyte culture through analysis of
factors in the processes of gynogenesis, including genotype selection, stage of ovule development, pretreatment, and culture
media containing nutritional components and phytohormones. The gynogenetic approach may be of great value in discovering novel
genetic recombinations. Application of double haploids in genetics and plant breeding is also highlighted. This review also
identifies some existing knowledge gaps where work may increase the efficiency of this process in different plant species. 相似文献
19.
Powdery mildew (Sphaerotheca fuliginea) resistance in melon is selectable at the haploid level 总被引:3,自引:0,他引:3
The major cause of powdery mildew in melons (Cucumis melo L.) is the fungus Sphaerotheca fuliginea. There are several cultivar- and season-specific races of this fungus. In order to control powdery mildew, it is important to introduce resistance to fungal infection into new cultivars during melon breeding. Haploid breeding is a powerful tool for the production of pure lines. In this study, it was investigated whether powdery mildew resistance could be manifested at the haploid level from two disease-resistant melon lines, PMR 45 and WMR 29. the effects of various races of S. fuliginea on diploid and haploid plants of PMR 45 and WMR 29 and of a disease-susceptible line, Fuyu 3 were measured. The responses of haploid and diploid plants to powdery mildew were identical. In addition, haploids that were generated from hybrids between Fuyu 3 and disease-resistant lines were examined. Seven out of 13 haploids from a Fuyu 3xPMR 45 cross and 10 out of 12 haploids from a Fuyu 3xWMR 29 cross were classified as resistant plants because they showed the same responses as their disease-resistant diploid parents to the various fungal races. These results indicate that resistance in PMR 45 and WMR 29 is selectable at the haploid level. All of the plant responses were observed by microscopy. A possible mechanism for generating powdery mildew resistance in two different melon lines is discussed. 相似文献
20.
Germanà MA 《Plant cell reports》2011,30(5):839-857
Plant breeding is focused on continuously increasing crop production to meet the needs of an ever-growing world population,
improving food quality to ensure a long and healthy life and address the problems of global warming and environment pollution,
together with the challenges of developing novel sources of biofuels. The breeders’ search for novel genetic combinations,
with which to select plants with improved traits to satisfy both farmers and consumers, is endless. About half of the dramatic
increase in crop yield obtained in the second half of the last century has been achieved thanks to the results of genetic
improvement, while the residual advance has been due to the enhanced management techniques (pest and disease control, fertilization,
and irrigation). Biotechnologies provide powerful tools for plant breeding, and among these ones, tissue culture, particularly
haploid and doubled haploid technology, can effectively help to select superior plants. In fact, haploids (Hs), which are
plants with gametophytic chromosome number, and doubled haploids (DHs), which are haploids that have undergone chromosome
duplication, represent a particularly attractive biotechnological method to accelerate plant breeding. Currently, haploid
technology, making possible through gametic embryogenesis the single-step development of complete homozygous lines from heterozygous
parents, has already had a huge impact on agricultural systems of many agronomically important crops, representing an integral
part in their improvement programmes. The aim of this review was to provide some background, recent advances, and future prospective
on the employment of haploid technology through gametic embryogenesis as a powerful tool to support plant breeding. 相似文献