• Journal of Plant Biology
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• v.14 no.1
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• pp.33-35
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• 1971

After topping, axillary buds of haploid plants derived from cultured anthers were treated with 0.4% aqueous solution of colchicine. Due to the high temperature and dry air at the time of treatment, most of the buds perished. A few months after the colchicine application, however, several shoots arose from the places where the dead buds were originally located. These shoots were mostly diploid. Induction of adventive shoots from the colchicine-treatedaxils was supposed to be rather effective method of obtaining diploid shoots from haploid plants. The diploid plants had larger floral organs than the haploid plants, and had good pollen fertility and seed setting. 24 bivalent chromosomes were observed at MI of the PMC's.

• Journal of Plant Biology
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• v.39 no.3
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• pp.185-188
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• 1996

Randomly amplified polymorphic DNAs were employed to study the genetic variation and gene introgression in potato dihaploids (2n=24) which were generated after interspecific pollination of tetraploid cultivars (2n=4X=48, Solanum tuberosum cv Irish Cobbler, Superior and Dejima) by haploid inducer clones (2n=2X=24, Solanum phureja 1.22, Hes-5 and Hes-6). Genetic variation and DNA marker segregation among dihaploids were observed. Most dihaploids contain S. tuberosum specific RAPD markers but haploid inducer-specific RAPD markers were also found in some dihaploids. Of six different arbitrary 10-mer oligonucletide primers which showed polymorphism betwen tetraploid cultivars and haploid inducers used, three generated amplification products which seemed to be derived from the S. phureja parent. Our results indicate that chromosomes of dihaploids may not be pure S. tuberosum and the dihaploids may not be produced by parthenogenesis.

• Journal of the Korean Society of Tobacco Science
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• v.4 no.1
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• pp.21-27
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• 1982

Six flue-cured cultivars of Nicotiana tabacum L., 15 possible $F_1$ hybrids and 15 $F_2$ populations among them, and 15 haploid populations of $F_1$ hybrids and 6 haploid from parents, were evaluated. The variances of general combining ability were predominant for all characters studied in $F_1$ hybrid and $F_2$ population, and in haploid populations of $F_1$ hybrids except leaf width, value and reducing sugar. There were significant correlations between generations in variances and ranks of parental GCA effects estimated from general combining ability analysis of $F_1,\;F_2$ and haploid generation of $F_1$ hybrids for yield, stem height, days to flower. leaves per plant, value and total alkaloids.

• Journal of the Korean Society of Tobacco Science
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• v.7 no.1
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• pp.93-96
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• 1985

This study was conducted to establish the maternal haploid method for the practical breeding of M tabacum using the interspeciflc hybridization between M tabacum and N. aflicana. The frequency of surviving seedling per seed capsule of interspecific hybridization was 4.15. Among them, the frequencies of maternal haploid and hybrid were 1.20 and 2.95, respectively. The chromosome numbers of n=24 for maternal haploid and 2n=47 for hybrid were identified in surviving seedling from interspecific hybridiztion. Except the chromosome number, distinguishable morphological differences of material haploid from hybrid were observed at seedling stage.

• Journal of Plant Biology
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• v.15 no.1
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• pp.28-32
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• 1972

Young haploid leaf derived from the anthers of tobacco plant was cultuerd and plantlets of various ploidies were obtained. When the leaf was put on the medium supplemented with kinetin as growth regulator, plantlets developed directly from the leaf, and the plants coming out in early stage of culture were all haploid. Plants developing in later stage were mostly haploids with some exception of diploid and aneuploid. Leaves were also cultured on the callus-inducing media supplemented with 2,4-D and kinetiion, and the calluses were sub-cultured for six months. Plants developed from these calluses were mostly aneuploids of various chromosome numbers. In view of the fact that the plants directly developed from the leaf were all haploid, the tissue of the original leaf explant was assumed to be uniform as far as chromosome number was concerned. On the other hand, it seemed that the occurrence of various ploidies in the plants derived from the calluses of same origin was the result of the influence of in vitro culture. Apical meristem tissues and various multicellular bodies were formed in the epidermal and inner mesophyll tissues as well as in the sub-epidermal cells.

• Korean Journal of Microbiology
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• v.29 no.1
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• pp.69-73
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• 1991

The chromosome of Fusarium species during the vegetatve nuclear divisions in hyphae were observed by use of HCl-Giemsa technique on light microscope. The haploid chromosome number of Fusarium anthophilum 7472 was n=7, n=6 in F. anthophilum 7481 and n=6 in F. oxysporum 7500. The haploid chromosome number was 7 in F. napiforme 6129 and F. napiforme 6144. Those of F. caucasicum F. caucasicum ATCC 18791 and F. aquaeductuum ATCC 15612 were n=5. F. coeruleum ATCC 20088 was n=6, n=8 in F. camptoceras ATCC 16065 and n=7 in F. sambucinum NRRL 13451. From these results and previous papers, it may be concluded that the basic haploid chromosome number of the genus Fusarium is n=4.

• Korean Journal of Plant Tissue Culture
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• v.28 no.1
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• pp.37-40
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• 2001

To optimize the in uitro chromosome doubling procedure in anther cultures of rice, anthers were cultured on callus induction medium with 0.001 to 0.1 mg/L colchicine for 30 days. The addition of colchicine slightly reduced callus formation and plant regeneration in comparison to the colchicine-free medium (control medium). This reduction was greater with higher concentration colchicine. Microspore-derived rice plants in control medium were found to be mainly haploid (50 to 58.8%) and doubled-haploid (31 to 40%) in anther culture of 3 Japonica and 1 Tonsil type cultivars. The application of 0.001 mg/L colchicine was increased to 54.3∼60.0% in the frequency of fertile doubled-haploid plants. These results indicate that the addition of colchicine to the callus induction medium is an efficient means to obtain doubled-haploid plants in anther cultures of rice.

• Journal of Plant Biotechnology
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• v.43 no.1
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• pp.12-20
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• 2016

Advances in DNA sequencing technologies have contributed to revolutionary understanding of many fundamental biological processes. With unprecedented cost-effective and high-throughput sequencing, a single laboratory can afford to de novo sequence the whole genome for species of interest. In addition, population genetic studies have been remarkably accelerated by numerous molecular markers identified from unbiased genome-wide sequences of population samples. As sequencing technologies have evolved very rapidly, acquiring appropriate individual plants or populations is a major bottleneck in plant research considering the complex nature of plant genome, such as heterozygosity, repetitiveness, and polyploidy. This challenge could be overcome by the old but effective method known as haploid induction. Haploid plants containing half of their sporophytic chromosomes can be rapidly generated mainly by culturing gametophytic cells such as ovules or pollens. Subsequent chromosome doubling in haploid plants can generate stable doubled haploid (DH) with perfect homozygosity. Here, classical methodology to generate and identify haploid plants or DH are summarized. In addition, haploid induction by epigenetic regulation of centromeric histone is explained. Furthermore, the utilization of haploid plant in the genomics era is discussed in the aspect of genome sequencing project and population genetic studies.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.5
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• pp.649-654
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• 1995

This study was conducted to investigate the utility and agronomic characteristics and use of cytoplasmic. male-sterile (CMS) haploid plants derived from interspecific cross between (male-sterile NC82$\times$burley21) F$_1$ plant (Nicotiana tabacum L.) and Nicotiana africana. Abundant seeds of high germinability were obtained when Nicotiana tabacum (cytoplasmic male-sterile F$_1$ plants) is pollinated by Nicotiana africana. Most of seedlings died at the cotyledonary stage. The remaining seedlings are viable F$_1$ hybrids or maternal haploids that can be easily distinguished. Number of interspecific Fl hybrids and matermal haploids per capsule obtained from the interspecific cross between cytoplasmic male-sterile tobacco F$_1$ plants and N.africana yielded 2.2 and 0.5 plants, respectively. Out of 149 CMS haploid plants obtained from interspecific cross, 102 plants showed green type while the others were yellow type for leaf and stem. This results agreed with the genetic ratios expected among haploid plants from the F$_1$ hybrids heterozygous for two recessive genes of yellow color of burley tobacco plant. Out of 83 CMS haploid plants inoculated with TMV, 48 plants showed resistant, while the others was susceptible. It agreed with the expected genetic ratios for a single dominant gene of TMV resistance. CMS haploid plant will be useful as a source material for breeding of CMS doubled haploid lines

• Korean Journal of Animal Reproduction
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• v.25 no.4
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• pp.305-315
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• 2001

In this study, the production of transgenic embryo was attempted by microinjection or round spermatid cultured with foreign DNA. At first, the expression of haploid spermatids specific gene, mTP1 in mouse and hPrm2 in hamster spermatids were investigated by RT-PCR method in testes of young mice and hamster testis. The specific gene expression first appeared at 18 days post partum (dpp) in mice spermatid and 20 dpp in hamster spermatid. Therefore, the round spermatids isolated from 17 dpp mice and 19 dpp hamster were used for the introduction of foreign EGFP gene into haploid round spermatids. For the introduction of EGFP gene haploid round spermatids suspended in medium including EGFP gene were treated with a different electric field strength at 0.11, 0.18 and 0.44 ㎸/cm. After electrical stimulation, viability of testicular sperm cells and 67.6%, 66.4% and 49.9%, in mice and 62.6%, 57.9% and 27% in hamster, respectively. These values were significantly lower than those of non-treated control groups 80.5% in mouse and 69.1% in hamster After 72 hrs culture, the highest expression rate of EGFP gene, 28.5% in mice and 32.1% in hamster were obtained from tile spermatogenic cells electroporated by the field strength or 0.18 ㎸/cm. Then, the ability of fertilization and embryonic development of haploid spermatids transfected with foreign EGFP gene were estimated by the microinjection of spermatids into hamster oocytes. The Irate pronuclear formation rate (77.5%) was lower than non-treated control (80%), and the cleavage rate of the treated group (58.8%) was lower than control (65%). To prove the foreign EGFP integration in hamster embryos, 2-cell stage hamster embryos were subjected to the observation under the fluorescence microscope, and the PCR analysis. As a result, about 44% of 2-cell embryos were showed the integration of EFGP gene into their genome. Therefore, These results suggest the possibility to produce transgenic hamsters by microinjection of haploid spermatid transfected with foreign DNA.