• 한국초지조사료학회지
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• 제17권1호
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• pp.1-10
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• 1997

Unreduced (2n) gametes are meiotic products (pollen or egg) having a sporophytic (somatic) chromosome number, resulting from abnormalities during either microsporogenesis or megasporogenesis. They occur naturally at a low frequency in many plant species. Unreduced (2n) gametes in plants can be identified for four possible ways as follow i) pollen size and/or shape differences between haploid (n) and diploid (2n) pollen, ii) ploidy analysis (chromosome number) of progeny or meiotic analysis (presence of dyads andlor triads at the microspore stage), iii) progeny performance and fertility and iv) dosage of isozyme and DNA markers. Unreduced (2n) gametes can be an effective breeding tool in synthesizing new cultivars, providing a unique method to maximizing heterozygosity, i.e., transferring a large proportion of the non-additive genetic effects (intra- and inter- locus interactions) h m parent to offspring and can also be used to overcome infertility of interploidy crosses. Sexual polyploidization through 2n gametes has been a major route to the formation of naturally occurring polyploids. The three mechanisms of 2n pollen formation in potato have been discovered as follow: i) parallel spindles (ps) or tripolar spindles (ts), ii) premature cytokinesis (pc-I, pc-2) and iii) synaptic mutants (sy-2, sy-3, sy-4). Genetic analysis indicated that the mechanisms of 2n gamete formation were controlled by single recessive gene in potato, alfalfa, red clover, etc., and by two recessive genes in wheat. The use of 2n gametes which can efficiently transfer germplasm fiom wild relatives to cultivated species, especially fiom diploid to tetraploid could make a contribution to the improvement of germplasm base in breeding programs.

• Journal of Plant Biology
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• 제13권2호
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• pp.1-10
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• 1970

This experiment surveys ecological and morphological phase on Prasiola sp. in the mountain torrent of Chodang-ri, Keunduck-myon, Samchuck-gun, Kangwon-do, Korea from November 1968 through January 1970 and the results obtained were summarized as follows. 1. The temperature of the surface water was 12.4$\pm$2.3$^{\circ}C$, and pH was 7.25$\pm$0.2. 2. The external forms of thallus are very variable, but its basic form likely lanceolated and ovated. 3. The length of thallus is 0.6cm-8.8cm (3.6$\pm$1.72cm), and the width, 0.2cm-5.5cm(1.7$\pm$0.92cm). (The inside of the parentheses the average for 500 individuals). 4. It is observed that thallus at the time of formation of a monospore is a monostratum cell whose thickness is 21$\pm$3.2$\mu$. 5. Thickness of thallus at the transveres section at the time of heteroplanogametes formation is 29.9$\pm$2.2$\mu$, and that of the female gametes cell is 6.3$\pm$1.7$\times$6.3$\pm$0.8$\mu$, and that of the male gametes cell is 2.8$\pm$0.6$\times$28.1$\pm$1.1$\mu$. 6. As for growth, it begins with apical growth, followed by marginal growth. It seems to grow, through cell division when microsopical papillae are produced in growth line cell of marginal rigion thus by fusioning microscopical papillae. 7. The two kinds of thallus, one produced from a monospore and other from a planozygotes, are both haplonts and observed as n-3. 8. It seems that a thallus sprouts in April and increases its number through a asexual reproduction by a monospore and begins a sexual reproduction in November by forming gametes. 9. Female gametes are produced 16 from one thallus cell, whose structure shows 8 cells in the surface view and 4 layers in transverse section. Male gametes are produced 128 from one thallus cell, 16 cells surface, 8 layers in transverse section.

• 식물분류학회지
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• 제51권1호
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• pp.100-102
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• 2021

The chromosome number of myoga ginger (Zingiber mioga (Thunb.) Roscoe: Zingiberaceae) has been reported as 2n = 22 for Chinese plants and 2n = 55 for Japanese plants. We checked the chromosome number of Z. mioga in plants collected in Jeollabuk-do and Jeollanam-do, Korea, and counted 2n = 44, the first report of this number for the species. As the basic chromosome number of Z. mioga is thought to be x = 11, Z. mioga plants in China, Korea, and Japan appear to be diploids, tetraploids, and pentaploids, respectively. In finding the tetraploid race of Z. mioga in Korea, we can hypothesize that the pentaploid race in Japan is derived through the fertilization of reduced gametes of the diploid race and unreduced gametes of the tetraploid race.

• 한국육종학회지
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• 제41권3호
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• pp.213-219
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• 2009

본 연구는 나리의 종간잡종 육성체계를 확립하는데 필요한 기초자료를 얻기 위하여 OA hybrid 중 자발적으로 생식세포 염색체가 배수화된 계통을 이용하여 후대 획득과 후대검정에 필요한 실험을 수행하여 얻은 결과를 요약하면 다음과 같다. 2n 화분을 생산하는 OA hybrid의 경우 화분의 채취시기에 따른 생존율과 발아율은 10월에 비해 6월이, 생존율은 n성 화분이, 발아율은 2n성 화분이 높았다. 2n 화분을 생산하는 2배체 OA hybrid와 2배체 또는 4배체 Asiatic 또는 Oriental hybrid간 교배시 모본과 부본을 달리함에 따라 후대 획득 수에 차이가 있었는데 OA hybrid를 부본으로 이용했을 때, 상대친을 Asiatic hybrid로 교배했을 때 후대획득이 용이하였다. 즉 A$\times$OA교배에서 후대 획득률이 0.64개체로 O$\times$OA교배에서의 후대 획득률 0.42개체보다 높았으며, OA$\times$A간 교배에서 후대 획득률이 0.40개체인 반면 OA$\times$O교배에서는 전혀 후대획득이 불가능하거나 극히 낮아 후대획득이 어려웠으며, 아울러 2n 화분을 생산하는 OA hybrid의 후대생산을 위한 상대친으로 4배체보다는 2배체가 효과적이었다. 2n 화분을 생산하는 OA hybrid와 Asiatic 또는 Oriental hybrid간 정역교배 결과, OA hybrid를 부본으로 교배했을 때, 상대친으로 Asiatic hybrid을 교배했을 때 후대획득이 용이하였다. 자발적인 2n 화분을 생산하는 2배체 OA hybrid의 여교잡 후대의 ploidy level의 측정결과, OA$\times$A교배에서는 3배체, AA$\times$OA, OO$\times$OA교배에서는 4배체임을 확인할 수 있었으나, O$\times$OA교배에서는 2배체, A$\times$OA교배에서는 2배체 또는 3배체로 확인되었다.

• 한국작물학회지
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• 제30권4호
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• pp.455-459
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• 1985

우수 이위체 clone을 선발하고 이를 FDR clone으로 육성하고자 본 실험 이 수행되었다. 1) 도입된 2X종자를 포장 및 온실에서 재배하여17 clone이 선발되었으며 이들의 특성이 조사되 고, 이들 Clone을 인공교배, 개방수분, 집단수분하여 그후대에서 18clone 이 선발되었다. 2) 선발된 clone들은 2n웅성과 2n자성배우자 형성에 대하여 조사되었다. 그중 D6-21만이 27∼30％의 2n웅성 배우자를 FDR에 의해 형성하였고. 다른 clone들은 2n웅성 배우자 형성율이 7％ 미만이었다. 3) 자성 2n배우자를 생성하는 clone은 발견되지 않았다.

• ALGAE
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• 제36권2호
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• pp.147-154
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• 2021

Kelp life history pathways alternate between macroscopic sporophytes that produce spores and microscopic gametophytes that produce gametes. Occasionally, an alternative pathway is seen. This study examined the circumstances by which the high latitude estuarine bull kelp, Nereocystis luetkeana, foregoes the "free-living microscopic stages by releasing embryonic sporophytes directly from sori. Sori were collected from adult N. luetkeana sporophytes from eight locations within Kachemak Bay, Alaska in 2018 and 2020 to examine spatial and temporal development of embryonic sporophytes on sori. Distinctions were made between sori collected from first-generation and overwintered adults to assess the influence of parental age on embryonic sporophyte release. Further distinctions were made between sori collected from attached and drifting individuals to assess the influence of the status of parental attachment to substrate on embryonic sporophyte release. Inspection of propagules released from sori after 48-h incubations indicated that embryonic sporophytes were occasionally released alongside viable spores. Though embryonic sporophytes were released from sori as early as spring, it was not evident that they were bound by seasonal or spatial limits. The percent of propagules that were embryonic sporophytes ranged from 0% to 100% but were not significantly different between first-generation and overwintered adults, nor were they different between attached and drifting individuals. Nevertheless, the characteristic of directly releasing embryonic sporophytes from adult sporophytes might have ecological advantages for N. luetkeana.

• 한국작물학회지
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• 제27권3호
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• pp.243-246
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• 1982

연맥의 2배체가 가지고 있는 유용한 유전자를 재배종인 6배체에 도입시키는 이론적인 구상을 이미 알려진 사실에 기초하여 논의하였으며 이 계획의 주요 요점은 (1) 서로 다른 배수 수준 사이의 교량 역할을 하는 이질6배체를 얻기 위하여 4배체인 Avena magna를 이용하는 것이다. 이 A. magna는 6배체 재배종인 A. sativa와는 2개의 게놈이 부분적으로 상동성을 가지거나 또는 하나는 공통적이고 나머지 하나는 부분적으로 공통성을 가지고 있기 때문에 AA BB 게놈 형태보다는 이들 사이에 보다 정상적인 접합이 이루어질 수 있기 때문이다. A. strigosa와 A. magna는 교배친화성이며 42% 이상의 임실율을 보이고 있다. (2) A. strigosa의 목적하는 유전자가 A. magna에 도입되어 있는 4배체를 선발하고 (3) 합성 5배체는 $2^n=21$인 모배우자를 생성함으로써 A. sativa와 완전 또는 거의 완전한 접합이 이루어지게 된다. (4) 결과적으로는 마지막 단계에서 $A^{As}$ 게놈에 대하여 이질성이지만 이것을 자식시키면 동질계통을 얻을 수 있게 된다.

• Fisheries and Aquatic Sciences
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• 제27권5호
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• pp.306-313
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• 2024

The genus Chirostoma is endemic from the Mesa Central of Mexico. It is conformed of 18 species and six subspecies. Five species are in some category of risk, because of this, Chirostoma jordani is an excellent model species to implement biotechnologies like gametes cryopreservation. Aim of present study was to evaluate fertilizing capacity of cryopreserved C. jordani sperm, as alternative to conservation and assisted reproduction in this specie and genus. Males and females were collected from wild Atlangatepec dam stock, Tlaxcala State, Mexico. Seminal quality was evaluated in fresh and cryopreserved semen with three cryoprotective agents (CPAs): 10% dimethyl sulfoxide (DMSO), 10% methanol (MeOH), 14% ethylene glycol (EG) and it was determined its post-thaw fertilizing capacity. Sperm motility percentage decreased during cryopreservation process (p < 0.05). There were not significant differences in post-thaw motility percentage between EG (53.5 ± 1.9%) and MeOH (53.3 ± 1.3%), but DMSO (50.3 ± 0.5%) was significantly different (p < 0.05). Results showed that 0.2 μL fresh semen were enough to fertilize 100% oocytes (n = 60). 10 μL DMSO and 5 μL MeOH and EG cryopreserved semen were necessary to fertilize oocytes 100% (n = 60) (p < 0.05). Cryopreservation and fertilization protocol for C. jordani sperm was efficient and it could be used for its assisted reproduction.

• 화훼연구
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• 제17권4호
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• pp.279-284
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• 2009

불임인 종간잡종 OA-1 $F_1$ hybrid(Oriental hybrid 'Mero Star' ${\times}$ Asiatic hybrid 'Connecticut King')의 임성을 회복하기 위해 카페인을 0.1, 0.3, 0.5%의 농도로 화뢰 내부에 직접 주입하였고 카페인 처리 후 OA-1 $F_1$ hybrid의 임성을 개화시 확인하였다. 임성을 회복한 $F_1$에 Asiatic hybrid 'Lanzarote'의 화분을 수분시켜 그 후대를 얻었다. 그 결과 0.3% caffeine 처리구는 16개의 자방 중 7개의 배를 치상하여 5개의 식물체를 획득할 수 있었다. 0.5% 처리구에서는 1개의 식물체만 얻었고 0.1% 처리구에서는 식물체를 얻을 수 없어 적정 카페인 처리 농도는 0.3%임을 확인할 수 있었고 이로부터 2n gametes로 예상되는 화분이 51%나 생성되었다. 교잡종 OA-2 ('Romero Star' ${\times}$ 'Lady Rosa')와 OA-3('Expression' ${\times}$ 'Lady Rosa')에 온도 단독 또는 caffeine과 온도를 병행하여 재식 후 8주-13주 동안 $13^{\circ}C$와 $28^{\circ}C$로 변온처리하여 발아율을 측정한 결과, 온도만 처리한 경우나 온도와 caffeine을 동시에 처리한 경우 간에는 큰 차이가 없었다. 적정 caffeine(0.3%)을 처리한 OA-1에 Asiatic hybrid 'Lanzarote'와 Oriental hybrid 'Sorbonne'을 각각 주두수분법으로 정역교배한 결과, A('Lanzarote') ${\times}$ OA-1 또는 OA-1 ${\times}$ A간 교배조합은 O('Sorbonne') ${\times}$ OA-1 또는 OA-1 ${\times}$ O 교배조합보다 식물체 획득률이 양호하였다. A ${\times}$ OA-1 또는 OA-1 ${\times}$ A로부터 획득된 후대는 GISH 분석에 의해 모두 3배체로 확인되었다.