• Current Research on Agriculture and Life Sciences
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• v.31 no.2
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• pp.75-82
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• 2013

Haploids are plants with a gametophytic number of chromosomes in their sporophytes. Androgenesis occurs from asymmetric division of pollen grains into generative cells and vegetative cells, followed by re-entry of the vegetative cell during S-phase, which causes microspores progress into G2/M transition in culture. One of the most interesting features of haploids is the possibility to produce doubled haploid (DH) individuals. Doubled haploidy is extremely useful to plant breeders because it enables shortened breeding periods and efficiency in selection of useful recessive agronomic traits. Doubled-haploid technology is not only applicable to breeding, but also to transformation programs of desired genes. In addition to practical breeding programs, DH lines provide useful materials of fundamental genetics including exploitation of QTLs and genes conferred with various agronomic traits by establishing DH populations. This paper provides historical overviews on androgenesis and describes several mechanisms associated with pollen embryogenesis, including mode of actions in pollen embryogenesis, mechanisms of chromosome doubling and factors affecting androgenesis. We also discuss recent progress in application of haploids to breeding, genes associated with in vitro response and drawbacks to anther culture for application of doubled haploids in crop breeding.

• Journal of the Korean Society of Tobacco Science
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• v.10 no.1
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• pp.21-26
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• 1988

Ten anther-derived doubled haploid (ADH) and 10 maternally-derived doubled haploid fines (MDH) from NC 2326 were evaluated in the field to compare their performance. Both anther-derived doubled haploid and maternally-derived doubled haploid lines were agronomically inferior to selfed parental variety for many parameters, but the degree of inferiority of the MDH lines were not significantly different from the selfed parental variety for any character investigated. The inferiority of the ADH lines were, however, significantly different from the selfed parental variety for yield, leaf length and width , and days to flower.

• Journal of Plant Biotechnology
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• v.5 no.1
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• pp.51-57
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• 2003

Doubled haploids have long been recognized as a valuable tool in plant breeding since it not only offers the quickest method of advancing heterozygous breeding lines to homozygosity, but also increased the selection efficiency over conventional procedures due to better discrimination between genotypes within any one generation. Salt tolerant mutants were obtained in rice the variety, 'Hawsungbyeo', through in vitro mutagenesis of in vitro cultured anther-derived calli. Various doses (30, 50, 70 and 90 Gy) of gamma ray were applied to investigate the effect of radiation on callus formation on medium containing 1% NaCl, green plant regeneration, frequency of selected doubled haploid mutants and of the salt tolerant screen. It was demonstrated that the dose of 30 and 50 Gy gamma rays had significant effects on callus formation, regeneration and selection of salt tolerance. No tolerant lines were obtained from non-mutagenized cultures. From gamma ray irradiated cultures, five tolerant lines ($M_2$generation) at germination stage and 13 tolerant lines ($M_3$genoration) at seedling stage were obtained. The frequency of salt tolerant mutants indicates that anther culture applied in connection with gamma rays is an effective way to improve salt tolerance.

• Journal of Plant Biotechnology
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• v.1 no.1
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• pp.56-60
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• 1999

Sexual reproduction is an essential process in the propagation of flowering plants. Recent advances in plant cell biology and biotechnology have brought new and powerful methodologies to investigate and manipulate the reproductive processes of angiosperms including agronomically important crop plants. Successful cryopreservation of maize, rye and triticale pollen and young embryos of microspore-and zygote-origine contributes to long term preservation of important plant germ-lines in gene banks. Discovering morphogenetic characteristics of the different developmental pathways taking place in wheat and maize androgenesis in vitro helps to influence the procedure to produce genetically and phenotipically stable homozygous doubled haploid plants for breeding purposes. Detailed ultrastructural and cell-biological studies on the developmental sequences of male and female gametophyte development in wheat, experimental protocols developed to isolate and micromanipulate egg cell protoplasts, make it possible to use plant gametes and the sexual route itself to produce genetically improved organisms. Plant gametes can become useful tools for crop improvement in the near future. Recent achievements by our laboratory in this field are reviewed in the present paper

• Journal of Plant Biotechnology
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• v.39 no.1
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• pp.13-22
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• 2012

Plant regeneration has been optimized increasingly by organogenesis and somatic embryogenesis using a range of explants with tissue culture improvements focusing on factors, such as the age of the explant, genotype, media supplements and $Agrobacterium$ co-cultivation. The production of haploids and doubled haploids using microspores has accelerated the production of homozygous lines in Brassicaceae crop plants. Somatic cell fusion has facilitated the development of interspecific and intergeneric hybrids in sexually incompatible species of $Brassica$. Crop improvement using somaclonal variation has also been achieved. Transformation technologies are being exploited routinely to elucidate the gene function and contribute to the development of novel enhanced crops. The $Agrobacterium$-mediated transformation is the most widely used approach for the introduction of transgenes into Brassicaceae, and $in$ $vitro$ regeneration is a key factor in developing an efficient transformation method in plants. Although many other Brassicaceae are used as model species for improving plant regeneration and transformation systems, this paper focuses on the recent technologies used to regenerate the most important Brassicaceae crop plants.

• Plant Breeding and Biotechnology
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• v.5 no.3
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• pp.204-212
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• 2017

There is a growing preference for using doubled haploids (DHs) in maize breeding programs because they reduce the time required to generate and evaluate new lines to 2 years or less. However, there is an urgent need for efficient techniques that accurately discriminate between haploid and diploid maize kernels. Here, we investigate the effects of several hormones and chemicals on the germination of haploid and diploid maize kernels, including auxin, cytokinin, ethylene, abscisic acid (ABA) biosynthesis inhibitor (fluridone), ABA catabolism inhibitor (diniconazole), methyl jasmonate (MeJA), and NaCl. Ethylene effectively stimulated the germination of both haploid and diploid maize kernels. The ABA biosynthesis inhibitor fluridone, the ABA catabolism inhibitor diniconazole, and MeJA selectively stimulated the germination of haploid maize kernels. By contrast, gibberellin, 1-naphthaleneacetic acid (NAA), kinetin, and NaCl inhibited the germination of both haploid and diploid maize kernels. These results indicate that the germination of haploid maize kernels is selectively stimulated by fluridone and diniconazole, and suggest that ABA-mediated germination of haploid maize kernels differs from that of diploid maize kernels and other plant seeds.

• Journal of Practical Agriculture & Fisheries Research
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• v.25 no.4
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• pp.90-102
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• 2024

Haploid/double haploid plants developed from isolated microspores can significantly accelerate plant breeding. Haploid plants can naturally double their chromosomes to create a pure homozygous line of diploid plants. We present a method for producing embryos from isolated microspores of hot peppers (Capsicum annuumL.). We analyzed the polyploidization levels of the regenerated plants. The donor plants produced the optimal stage of microspores following short-term growth under low-intensity light, which resulted in high rates of embryogenesis and cotyledonary embryogenesis. To find an efficient culture method, liquid, doubled-layer, and 2-step cultures were tested. Liquid culture yielded the highest number of embryos, whereas the highest efficiency for cotyledonary embryogenesis was afforded by the doubled-layer culture. When normal cotyledonary embryos were transplanted onto a regeneration medium, they developed into complete plants. From these, 208 plants were tested via flow cytometric analysis, and 35.6% and 72.7% of the chromosomes from the Milyang-jare and LV2319 genotypes, respectively, were found to be spontaneous double haploids. These results are the same as those obtained on analyzing horticultural characteristics, including the size of leaves and the size and shape of fruits. The present study provides information on the practical application of isolated microspore culture of hot peppers, factors that affect embryogenesis, and methods for polyploidy testing.

• 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 CROP SCIENCE
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• v.34 no.2
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• pp.142-146
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• 1989

Anther and/or tissue culture of cross pollinated crops would be very important because it can result in the direct use of haploids or doubled haploids for developing superior hybrids or varieties. The objective of the study was to investigate the response frequencies in anther and/or tissue-cultured hybrids of corn. pearl millet and buckwheat to identify agronomically acceptable germplasm of the crops. 27 crosses of corn inbred lines were evaluated by plating their anthers on N6. MS and Yu-Pei media. Two genotypes of FR1l41/FR16 hybrid cultured on N6 medium and Fla 2BT73/S6013 hybrid cultured on N6 medium responded with one anther producing calli when plated after 5$^{\circ}C$ low temperature treatment for one week. Immature embryos of corn hybrid Suwon 19 responded producing calli that were regenerated to plants at a 8.6 percent success rate. Of the 20 corn hybrids. immature tessels of FR1l41/FR16. B68/A1l6N//KS15. KS16/KS17. GA209/DB578 and SDB126/GA209 crosses responded at a relatively higher success rate producing calli that were regenerated to plants. In tissue culture of elongating culms of pearl millet x Napier grass interspecific hybrid. 2.5-4.0mm long pieces of the culm were good for callus induction resulting in higher success rate. The epicotyl of buckwheat was very good for tissue culture. and the node produced the plants regenerated directly without callus induction on the B5 medium containing I ppm BA and 0.05 ppm IBA. There were great differences in response to anther and/or tissue culture of corn, pearl millet and buckwheat due to genotype x medium and environment interactions.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.281-281
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• 2022

Rice is a staple crop used by more than 50% of the world's population. However, in rapidly changing climates such as abnormal high temperatures and typhoons, the food security of rice is greatly threatened. Plant factories have the advantage of being able to grow crops regardless of climate change, so they can be a response to climate change. However, in plant factories, crops are grown by placing the culture bed vertically, so shorter crops are more efficient. Therefore, in order to search for genes related to the height of rice, QTL analysis was performed by investigating the plant height of Cheongcheong/Nagdong doubled haploids from 2017 to 2021. Plant height of rice investigated for five years showed a normal distribution, meaning that genes related to rice height are quantitative traits. As a result of QTL analysis, a total of 12 QTLs were detected, and QTLs overlapped for 5 years in RM12285-RM212 on chromosome 1. Also, The QTLs of plant height detected in 2019 has a LOD score of 17.64 in RM12285-RM212 region of chromosome 1. As a result of QTL analysis, 44 height-related genes were searched from the detected chromosomes, and among them, Os01g0757200 in RM 12285-RM212 on chromosome 1 region, named OsGA2ox3q1, were selected as genes related to the height of rice. The relative gene expression level of OsGA2ox3q1 was highly expressed in cultivar with short culm lines, and was low expressed in cultivar with long culm lines. OsGA2ox3q1 can be used to breed semi-dwarf cultivar in rice more efficiently.