• Korean Journal of Plant Taxonomy
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• v.45 no.4
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• pp.353-361
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• 2015

Spatio-temporal variation in fruit set in orchids would affect long-term population viability and will influence genetic diversity over many generations. The aim of this study was to examine the breeding system of the nectariferous terrestrial orchid Epipactis thunbergii, to specifically determine levels of fruit set in terms of time and space under natural conditions. We examined pollination under natural conditions and conducted hand pollination experiments during a 2-year survey in four populations located along 1.5 km of coastal line in Jinguiri (rual village) [Jeollanam-do (province), southern Korea]. We found that, over a 2-year period, levels of percentage of fruit set were similar within patches of the four populations. By contrast, we detected significant differences in the percentage of fruit set among patches. We also found that plants with larger inflorescence size produced significantly more fruits than plants with fewer flowers. Over a 2-year period, the percentage of fruit set for E. thunbergii was similar but low (14.1%) compared to that averaged for eighty-four rewarding species (37.1%). However, an increase in fruit set was achieved by hand-pollinations: artificial self-pollination (90.5-95.2%), artificial geitonogamy (94.7-95.0%), and cross-pollination (artificial xenogamy, 91.3-91.4%). No emasculated flowers produced fruits and no automatic pollination was found in E. thunbergii. Our findings suggest that E. thunbergii is a self-compatible terrestrial orchid that depends on pollinators (insects) to achieve fruit set in natural habitats, and that local environmental conditions were similar over a period of 2 years in the study area. Our results also highlight the cryptic variation of fruit production in time, but more pronounced variability in space.

• Korean Journal of Environment and Ecology
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• v.23 no.1
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• pp.50-55
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• 2009

To understand the status of the migrating Oriental Honey Buzzard(Pernis ptilorhynchus) in Korea, we carried out a preliminary study on the number and local movements of the Honey Buzzard from September 2005 to October 2007 at Hongdo Island, Jeonnam Province, Korea. A total of 702 Honey Buzzards in 2005, 404 individuals in 2006, and 659 individuals in 2007 were recorded during the fall migration season, but during the spring migration season only two and eight birds were observed in 2006 and 2007 respectively. The migrating Honey Buzzard showed peak numbers from 20 September to 5 October at the study site. According to observation of arrival time of538 Honey Buzzard in October 2007, a total of 2l6 birds(40.l %) were passing over Hongdo Island between 7:00 AM to 8:00 AM, rising skyward on columns of warm air. This suggests the use of thermal currents and avoidance of nocturnal movement for crossing water. They preferred moderate winds(<5 m/s in speed) from northwest, but the migrating number apparently decreased in case of strong winds (${\geqq}5 m/s$). This suggests that wind speed and direction are important environmental factors for migration of the Oriental Honey Buzzard. At present, it is unclear which breeding population(from north-eastern China or Japan) passes over Hongdo Island. Moreover, it is difficult to prove migration route and to understand migratory behaviors of the Oriental Honey Buzzard in Korea. To prove the breeding sites and routes of the migrants over the study site, we need more detailed and further studies such as satellite tracking researches.

• Korean Journal of Environmental Biology
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• v.25 no.2
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• pp.94-99
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• 2007

To investigate the spatial distribution and daily calling pattern of the Gold-spotted pond frog, Rana chosenica, in Chungju city and Chungwon gun, Chungbuk province, Korea, we divided the study area into 226 plots with a $2{\times}2km^2$ plot on the map, of which we assigned 32 plots for monitoring populations. Call monitoring on whether the species are present or not were conducted for 5 minutes in between sunset and the midnight from at the end of May to July in 2006. Gold-spotted pond frogs were detected at least once four out of 32 plots. Using program Presence, we obtained site occupancy rate as 0.170 which was quite low compared with other species, while detection probability was 0.66 that propose at least three times to visit the monitoring site to confirm the absence of the frogs. The frogs were actively calling from 21:00 to 02:00, and the number of calling male was significantly and highly correlated with water temperature and humidity. This study shows the present status of the Gold-spotted pond frogs in Chungju city and Chungwon gun and we suggests various effective monitoring methods based on the this study.

• Reproductive and Developmental Biology
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• v.28 no.1
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• pp.37-43
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• 2004

This study was carried out to investigate PSS (Porcine Stress Syndrome) with the PSE (Pale, Soft, Exudative) in 319 different pigs(Yorkshire 150; Landrace 89 and Duroc 80). The PCR-RFLP method was adapted to detect the ryanodine receptor (RYR 1) gene mutation and to estimate the genotype frequency of the RYR1 gene in breeding pig population. The DNA samples were collected from hair follicles of pigs of Yorkshire, Landrace and Duroc. After DNA amplification by PCR, the PCR products were digested by restriction enzyme, Cfo I. Primary PCR products of ryanodine receptor gene were length of 659 bp in hair follicle and their second PCR products were length of 522 bp in hair follicle. The exon region (522 bp) including point mutation ($C \arrow T; Arg \arrow Cys$) in the porcine ryanodine receptor gene, which is a causal mutation for PSS, was digested with Cfo I restriction enzyme. The RYR1 gene was classifed into three genotypes by agarose gel electrophoresis. The normal homozygous (NN) individuals showed two DNA fragments consisted of 439 and 83 bp. The mutant homozygous (nn) individuals showed only one DNA fragment 522 bp. In addition, all three fragments (522, 439 and 83 bp) were showed in heterozygous (Nn) carrier animals. The normal homozygous (NN), heterozygous (Nn) and mutant homozygous (nn) were 98.00, 2.00 and 0.00% in Yorkshire pigs, 87.64, 11.24 and 1.12% in Landrace, 100.00, 0.00 and 0.00% in Duroc, respectively. The gene frequencies of N and n were 0.990 and 0.010 in Yorkshire pigs, 0.933 and 0.067 in Landrace, 1.000 and 0.000 in Duroc, respectively.

• Horticultural Science & Technology
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• v.33 no.5
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• pp.722-729
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• 2015

Powdery mildew (PM) caused by Podosphaera aphanis is a major disease that can result in significant yield losses in strawberry (Fragaria ${\times}$ ananassa Duchesne). For preventing PM, pesticides are usually applied in strawberry. In this study, molecular markers were developed to increase breeding efficiency of PM-resistance cultivars by marker-assisted selection (MAS). An $F_2$ population derived from a cross between PM-resistance 'Seolhyang' and PM-susceptibility 'Akihime' was evaluated for disease resistance to PM and RAPD (random amplification of polymorphic DNA)-BSA (bulked segregant analysis). Among 200 RAPD primers tested, OPE10 primer amplified a 311bp-band present in with 331bp. Sequence alignment performed for searching polymorphisms and six single nucleotide polymorphism (SNP) were found in amplified regions. To develop polymorphic marker for distinguishing between resistant and susceptible, RAPD was converted to cleaved amplified polymorphic sequence (CAPS) marker. Among restriction enzymes associated with six SNPs, Eae I (Y/GGCCR) was successfully digested to 231bp in susceptible. The results suggest that the selected CAPS marker could be used for increasing efficiency of selecting powdery mildew resistant strawberry in breeding system.

• Korean Journal of Breeding Science
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• v.41 no.4
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• pp.620-624
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• 2009

"Egreen" rye (Secale cereale L.) was developed by National Institute of Crop Science (NICS), RDA. It was released in 2007 because of its excellent earliness and yield potential. Crossing was made by an open pollination with 10 rye lines in 1995. Many lines from the open pollinated population were handled in a mass selection program in subsequent generations. Among them the line 'SR95POP-S1-116-1-1-2'was selected for earliness and promising agronomic appearance and placed in yield trial for two years from 2003 to 2004. In 2005, it was designated "Homil 34" and subjected to regional yield trials. Over 3 years, "Egreen" averaged 8.34 MT ha-1 of forage yield (based on dry matter) harvested at the heading date of check variety "Olhomil", which was superior to other varieties such as "Olhomil" and "Koolgrazer" with an increase of 8% and 10%, respectively. Heading date of "Egreen" was April 22, 3 days earlier than that of "Olhomil". It would be recommended as a winter crop forforage and green manure before planting either maize or rice in Korea.

• Korean Journal of Breeding Science
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• v.41 no.3
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• pp.236-243
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• 2009

This study was conducted to develop a japonica-type rice cultivar with brown planthopper (BPH) resistance using DNA markers. A doubled haploid (DH) population consisting of 120 pure-lines was established by anther culture of $F_1$ hybrids between 'Samgang', a Tongil type BPH resistance cultivar, and 'Nagdong', a japonica cultivar. To determine the map position of genes responsible for BPH resistance in rice, a genetic map was constructed based on 120 DH lines. A total of 162 molecular markers were classified into 12 linkage groups, covering 1,884 Kosami centimorgan (cM) with an average of 11.6 cM. Five QTLs (qBPR3, qBPR6, qBPR7, qBPR8, and qBPR12) associated with BPH resistance were identified and mapped on chromosomes 3, 6, 7, 8, and 12, respectively, using the genetic map constructed in this study. To analyze the relationship between BPH resistance and agronomic traits, a total of eight QTLs related to the agronomic traits were detected on 12 rice chromosomes. In an analysis of relationships, three QTLs (qBPR3, qBPR7, and qBPR8) showed a linkage with tested agronomic traits. A QTL (qBPR3) located on chromosome 3 (RM282-3023) was closely linked to culm length (qCL3). The QTL (qBPR8) for BPH resistance on the short arm of chromosome 8 also overlapped the region detected in culm length (qCL8).

• Korean Journal of Breeding Science
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• v.41 no.3
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• pp.252-260
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• 2009

Rice is the most important cereal crop not only in supplying the basic staple food for more than half of the world's population but also as a model plant for functional genomic studies of monocotyledons. Although rice transformation method using A. tumefaciens has already been widely used to generate transgenic plants, the transformation rate is still low in most Korean elite cultivars. We made several modifications of the standard protocol especially in the co-cultivation step to improve the efficiency of the rice transformation. The co-culture medium was modified by the addition of three antioxidant compounds (10.5 mg/L L-cysteine, 1 mM sodium thiosulfate, 1 mM dithiothreitol) and of Agrobacterium growth-inhibiting agent (5 mg/L silver nitrate). Co-cultivation temperature ($23.5^{\circ}C$ for 1 day, $26.5^{\circ}C$ for 6 days) and duration (7 days) were also changed. The plasmid of pMJC-GB-GUS carrying the GUS reporter gene and the bar gene as the selectable marker was used to evaluate the efficiency of the transformation. After co-cultivation, a high level of GUS gene expression was observed in calli treated with the modified method. It is likely that those newly added compounds helped to minimize the damage due to oxidative bursts during plant cell-Agrobacterium interaction and to prevent necrosis of rice cells. And the transformation rate under the modified method was also remarkably increased approximately 8-fold in Heungnambyeo and 2-fold in Ilmibyeo as compared to the corresponding standard method. Furthermore, we could produce the transgenic plants stably from Ilpumbyeo which is a high-quality rice but its transformation rate is extremely low. Transformation and the copy number of transgenes were confirmed by PCR, bar strip and Southern blot analysis. The improved method would attribute reducing the effort and the time required to produce a large number of transgenic rice plants.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.12
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• pp.1836-1843
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• 2019

Objective: Social genetic effects (SGE) are an important genetic component for growth, group productivity, and welfare in pigs. The present study was conducted to evaluate i) the feasibility of the single-step genomic best linear unbiased prediction (ssGBLUP) approach with the inclusion of SGE in the model in pigs, and ii) the changes in the contribution of heritable SGE to the phenotypic variance with different scaling ${\omega}$ constants for genomic relationships. Methods: The dataset included performance tested growth rate records (average daily gain) from 13,166 and 21,762 pigs Landrace (LR) and Yorkshire (YS), respectively. A total of 1,041 (LR) and 964 (YS) pigs were genotyped using the Illumina PorcineSNP60 v2 BeadChip panel. With the BLUPF90 software package, genetic parameters were estimated using a modified animal model for competitive traits. Giving a fixed weight to pedigree relationships (${\tau}:1$), several weights (${\omega}_{xx}$, 0.1 to 1.0; with a 0.1 interval) were scaled with the genomic relationship for best model fit with Akaike information criterion (AIC). Results: The genetic variances and total heritability estimates ($T^2$) were mostly higher with ssGBLUP than in the pedigree-based analysis. The model AIC value increased with any level of ${\omega}$ other than 0.6 and 0.5 in LR and YS, respectively, indicating the worse fit of those models. The theoretical accuracies of direct and social breeding value were increased by decreasing ${\omega}$ in both breeds, indicating the better accuracy of ${\omega}_{0.1}$ models. Therefore, the optimal values of ${\omega}$ to minimize AIC and to increase theoretical accuracy were 0.6 in LR and 0.5 in YS. Conclusion: In conclusion, single-step ssGBLUP model fitting SGE showed significant improvement in accuracy compared with the pedigree-based analysis method; therefore, it could be implemented in a pig population for genomic selection based on SGE, especially in South Korean populations, with appropriate further adjustment of tuning parameters for relationship matrices.

• Animal Bioscience
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• v.34 no.11
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• pp.1749-1756
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• 2021

Objective: Microminipig (MMP) is a miniature pig with an extra small body size for experimental use. In the present study, the occurrence of stillbirths and their genetic association with swine leukocyte antigen (SLA) class II haplotypes were evaluated in a population of MMPs. Methods: The occurrences of stillbirth and genetic association with SLA class II haplotypes using 483 stillborn and 2,246 live piglets, and their parents were compared among the three groups of newborn piglet litters; an all stillborn (AS) group consisting of only stillborn piglet litters, a partial stillborn (PS) group consisting of stillborn and live piglet litters, and an all alive (AA) group consisting of only live piglet litters. Results: The incidence of stillborn piglets was 483/2,729 (17.7%). Distributions of litter sizes, numbers of stillborn piglets in a litter, parities, and gestation periods were distinct among the three groups. The frequencies of low resolution haplotype (Lr)-0.7 or Lr-0.23 were higher in the AS group than in the PS or AA groups. In sires, the frequency of Lr-0.7 associated with the AS group was significantly higher in the AS group than with the AA group. In dams, the frequency of Lr-0.23 was significantly higher in the AS group than in the PS or AA groups, whereas the frequency of Lr-0.7 was not significantly different. Conclusion: The incidence of stillborn piglets in MMPs appears to be higher than those in other pig breeds. Several traits related with stillbirths such as the number of stillborn piglets and parities of the AS group were different from those of the PS and AA groups. Specific SLA class II haplotypes were associated significantly with a high incidence of stillbirths and could be used as genetic markers to adopt breeding strategies to lower the rate of stillbirth in MMPs.