• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.4
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• pp.346-350
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• 2009

The cultivated radish (Raphanus sativus L.) is a major vegetable crop in the world wide and fast-growing species that grows inhabitats of six continents. It is very important to determine hybrid seed purity in the production of hybrid Brassica vegetable seeds to avoid unacceptable contamination with self-inbred (sib) seeds. The use of random amplified polymorphic DNA (RAPD) markers for evaluating seed purity in $F_2$-hybrid radish cultivars demonstrated. One hundred eighty seeds from the F1 male and female harvest were subsequently screened for seed purity using 13 primers. The 13 primers result in 17 cultivar-specific bands and 23 variable RAPD bands scored for cultivar. RAPD analysis of hybrid seeds from the harvest revealed 128 seeds tested except underdevelopment and decayed seeds were sibs. Especially, $F_2$ hybrids of radish, OPC13, OPD20 were presented clear hybrid bands. It maintains higher than average level of genetic diversity compared with their correspondent parents. RAPD amplification of DNA extracted from germinated individuals from the female harvest reveal that 10 of 208 seeds tested were self-inbred (4.8%). RAPD analysis of hybrid seeds from the male harvest revealed 7 of the 208 seeds tested were sibs (3.4%). The RAPD may lead to a better insight in to the hybrid seed purity.

• Korean Journal of Plant Tissue Culture
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• v.24 no.4
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• pp.239-256
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• 1997

Plants belonging to the category of 2n apomixis or agamospermy form embryos and seeds without the processes of normal meiosis and syngamy. Seeds produced in this way have identical genotype of their maternal parent. Three different types of agamospermy are recognized: diplospory, apospory, and adventitious (adventive) embryony. $F_1$ hybrid cultivars cannot be used as seed sources in the next ($F_2$) generation because this generation would be extremely variable as a result of genetic segregation. Hybrid vigor is also reduced in the $F_2$ generation. Therefore, parental stocks for hybrid seed production need to be maintained and cross must be continuously repeated. Agamospermic 2n apomixis would make it possible to fix the genotype of a superior variety so that clonal seeds faithfully representing that genotype could be continuously and cheaply produced independent of pollination. That is, $F_1$ hybrid seeds could be produced for many generations without loss of vigor or genotype alteration. Production of apomictic $F_1$ hybrid seed would be simplified because line isolation would not be necessary to produce seed or to maintain parental lines, and the use of male-sterile lines could be avoided. Overall, apomixis would enable a significant reduction in hybrid seed production costs. Additionally, the production of clonal seed is not only important for seed propagated crops, but also for the propagation of heterozygous fruit trees and timbers. Clonal seed would help avoid costly and time-consuming vegetative propagating methods that are currently used to ensure the large-scale production of these plants. Apomixis is scattered throughout the plant kingdom, but few important agricultural crops possess this trait Therefore, most research to date has centered on introgressing the trait of apomixis into agricultural crops such as wheat, maize, and some forage grasses from wild distant relatives by traditional cross breeding. The classical breeding approach, however is slow and often impeded by many breeding barriers. These problems could be surmounted by taking mutagenesis or molecular approach. Arabidopsis thaliana is a tiny sexually reproducing plant and is convenient in constructing and screening in molecular researches. Male-sterile mutants of Arabidopsis are particularly suitable genetic background for mutagenesis and screening for apomictic mutants. Molecular approaches towards isolating the genes controlling the apomictic process are feasible. Direct isolation of genes conferring apomixis development would greatly facilitate the transfer of this trait to wide variety of crops. Such studies are now in progress.

• Korean Journal of Medicinal Crop Science
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• v.17 no.3
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• pp.198-203
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• 2009

Isatis tinctoria var. yezoensis (Ohwi) Ohwi (Cruciferae) is one of major natural dyeing crops in the world and also have used as a medicinal plant in Korea. We evaluated seed purity in $F_1$-hybrid accessions using amplified fragment length polymorphism (AFLP) markers. One hundred sixty seeds from the male and female harvests were subsequently screened for seed purity with ten primers. The 13 accession-specific bands and many variable AFLP bands scored for accessions. Especially, E-AAC/M-CAA and E-AAG/M-CAT were presented clear hybrid bands for $F_1$ hybrids. $F_1$ hybrids maintained higher average level of genetic diversity compared with their correspondent parents. Self-inbred seeds from the female and male harvests were revealed 8.0% and 5.0%, respectively. The AFLP may lead to a better insight in to the hybrid seed purity test in I. tinctoria var. yezoensis.

• Journal of Korean Society of Forest Science
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• v.96 no.3
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• pp.290-294
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• 2007

Interspecific hybrid seedlings by artificial crossing of Genus Quercus (Q. serrata, Q. dentata, Q. mongolica var. crispula, Q. aliena) were planted at nursery in Tottori University. Seedlings of hybrids by natural crossing(Q. fabri and $Q.{\times}mccormickii$) were selected and planted at Hiruzen district in Tottori University. Artificial interspecific hybrid $F_1$ and natural hybrid $F_1$ bloomed when they were 4 years old and 3 years old, respectively. The pollen fertility and seed viability were investigated from the bloomed individuals in 2001. The germination percentages of the pollens of artificial interspecific hybrid were more than 84% except one individual, and the extension of pollen tubes was normal. The normal seed percentages of artificial interspecific hybrid were more than 90% similar to parents. Germination percentages of normal seed of natural crossing family were more than 64%, respectively, and selfed offsprings of Q. fabri, and $Q.{\times}mccormickii$ hade high reproductive ability.

• Weed & Turfgrass Science
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• v.4 no.1
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• pp.35-43
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• 2015

To assess the dormancy associated weedy risk of the F1 hybrid generated by hybridization between Brassica juncea (maternal) and Brassica napus (paternal), seed germination, dormancy and longevity were examined sequentially after seed harvest. The F1 hybrids exhibited the intermediate characteristics of their parents in seed germination and dormancy with relatively high dormancy rate of 41.1%. In summer, F1 hybrid seeds buried in the 3 cm soil exhibited greater viability (52.4%) than those in the soil surface with greater seed longevity (74.6%) than its maternal (63.3%) and paternal (33.7%) parents at 100 days of over-summering in soil. In winter, F1 seeds buried in the soil surface were more viable than those in the 3 cm soil with greater seed longevity (83.5%) than its maternal (39.0%) and paternal (71.7%) parents at 100 days of over-wintering in soil. Therefore, it is concluded that F1 hybrid resulted from gene flow from OSR to mustard has high seed dormancy and longevity during summer and winter, suggesting its weedy risk potential. Further studies are required to examine the reproductivity and fitness cost of F1 hybrid to make a clearer conclusion of its weedy risk.

• Journal of Ginseng Research
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• v.21 no.2
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• pp.85-90
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• 1997

This study was carried out to clarify the cause of incompatibility in interspecific hybrid plant between Panax ginseng and p. quinquefolium. The floral structure of F,(p.g. x p.q.) hybrid was normal because the redundant anther was 0.2 mm longer than pistil in Fl hybrid and the size and structure of redundant carpel in F, hybrid were similar to P. ginseng and p. quiquefolium Pollens of $F_1$ hybrid did not germinate on stigma of P-quinquefolium but germinated well on stigma of P. ginseng. Pollen tube was able to penetrate styles completely and seed harvest rate was 16.8% in field. However on stigma of $F_1$ hybrid, Pollen did not germinate when P. ginseng was used as male Parent. In addition, the growth of pollen tube was halted on style and seed was not set when P qlfinquefoEi2a was used as male Parent. These suggest that the inhibitor of pollen germination present on stigma caused $F_1$ hybrid sterility. It took 5 hours for pollen grains to germinate, 12 hours to arrive at in trance of ovule, 16 hours to penetrate micropyles in Panax ginseng.

• Weed & Turfgrass Science
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• v.5 no.4
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• pp.196-202
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• 2016

With increasing LM soybean import, the concern about unintentional gene flow from LM soybean to wild soybean and consequential weedy risk has been growing. Therefore, we conducted this study to characterize seed traits including germination of hybrids resulted from gene flow from LM soybean to wild soybean in comparison with their parents, LM soybean and wild soybean. Pollen-donor LM soybean seeds were much greater and heavier (about 15.0 g of 100 seed weight) than F2 hybrid (5.7 g), while pollen-recipient wild soybean and F1 hybrid seeds were smallest and lightest (about 2.5 g). F2 hybrid was brown, intermediate between yellow LM soybean seed and black wild soybean seed. These findings indicate that F1 hybrid seeds show similar characteristics with wild soybean, while F2 hybrid seeds show intermediate color and size between two parents. F2 hybrid seed showed intermediate traits between two parents in germination and dormancy rates, which were 35% and 65%, respectively. LM soybean showed no dormancy, while wild soybean showed greater than 90% dormancy. This finding indicates that F2 hybrid show intermediate characteristics in seed germination with high dormancy trait, suggesting a potential weediness of hybrids resulted from gene flow from LM soybean to wild soybean.

• Journal of Life Science
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• v.18 no.7
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• pp.907-911
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• 2008

Radish (Raphanus sativus L.) is one of very important crop plants in the world. It is very important to determine hybrid seed quality in the production of hybrid Brassica vegetable seeds to avoid unacceptable contamination with self-inbred (sib) seeds. The allozyme for evaluating seed purity in a commercial $F_1-hybrid$ radish cultivar is demonstrated. Three hundred sixty seeds from the male and female harvest were subsequently screened for seed purity using 27 isozyme loci. Especially, F1 hybrids of radish, Per-1 ($aa{\times}bb$), Lap-1 ($aa{\times}bb$), Est-1 ($aa{\times}bb$) were presented clear hybrid bands. Est-1 locus revealed that 15 (8.3%) seeds from the female harvest and 26 (14.4%) seeds from the male harvest were sibs. It maintains higher than average level of genetic diversity compared with their correspondent parents. Shannon's index of phenotypic diversity (I) of hybrids was the highest of all accessions (R. sativus L. cv. Daepeng, R. sativus L. cv. Backza, and their hybrids). The allozyme may lead to a better insight into the hybrid seed purity.

• Journal of the Korean Society of Tobacco Science
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• v.20 no.2
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• pp.166-171
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• 1998

In order to improve the efficiency of F$_1$ hybrid seeds production(KF 114), some experiments were carried out in a greenhouse this year. Mother plant(MSNC567) and pollen plant(NC) were grown in some pots (30 x 30cm, WxH). The gathered pollens were mixed with celite, pollen deluent dusts and stored in refrigerator at l$0^{\circ}C$ before pollination. To establish the critical range of the mixed rate and the storage period of pollens, the change in a percent of capsule set, number of seed and seed weight per capsule, weight of 1000 seeds and germination percent of seed resulted of pollination with pollen deluent dusts were investigated. The results are as follows; Percent of capsule set showed the mixed rate 1:5 resulted in no difference and those of 1:10 and 1:20 decreased about 5 ～15% when compared with trials using pollen alone. There was no difference among duration of storage in a same mixed rate. Numbers of seed per capsule showed a significant difference among the mixed rates and among durations of storage. Numbers of seed per capsule were decreased about 55 ～ 90 % as the mixed rate increase, about 2 ～ 28 % as the duration of storage increase. Weight of seed per capsule decreased about 16 ～ 23 % as the duration increase and decreased about 3 ～ 89 % as the mixed rate increase when compared with trials using pollen alone. Weight of 1000 seeds showed non significant difference among duration of storage but were higher than trials used pollen alone as the mixed rate increase.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.6
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• pp.424-428
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• 2003

This study was conducted to find out the optimum cultural method for hybrid seed production of Chalok 2. Higher seed yield was obtained when KW3 was used as a seed parent (female). KW7 was shown Higher barren stalk occurrence which caused significant seed yield reduction when it was used as a seed parent (female). The ratio of female (KW3) to male (KW7) rows with 4 to 1 had higher seed yield than that of 2:1 or 3:1. In case of using KW3 toy a seed parent, KW3 was susceptible to stem and ear rotting disease. The 35th day after silking was optimal period to harvest due to higher 100-grain weight, lower rotten grain, and higher germination rate.