• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.3
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• pp.243-252
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• 1985

The mechanism of reproductive cycle of longchin goby Chasmichthys dolichognathus was investigated for the annual variations of gonadosomatic index(GSI), histological changes of gonad, reproductive cycle, and initiating and terminating factors of the breeding season. The experimental fish were captured in the tide pool of Tongbaeksom, Pusan, Korea from February 1983 to September 1984. Experimental fish for the study of initiating and terminating factors of the breeding season were maintained in filtered recirculating aquariums and exposed to various temperature and photoperiod regimes. The ovary is a pair of sac-shaped organ, and the testicular structure is tubular and it is connected to the seminal vesicle which is located at the posterior end of the testis. GSI began to increase from February when the water temperature began to increase and reached peak in April. It began to decrease from August, the top water temperature season, and maintained relatively low values until January. The annual reproductive cycle includes successive six developmental stages : early growing from December to February, late growing from January to March, early mature from February to May, late mature and ripe from March to August, spawning from April to July, degeneration and resting stage from May to December. An experimental study based on the reproductive cycle of this species indicated that rising temperature under long photoperiod during spring stimulated gonadal maturation, whereas terminating factor of the breeding season with recrudescence of the gonads was demonstrated as high water temperature during summer regardless of photoperiod.

• Korean Journal of Environment and Ecology
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• v.22 no.3
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• pp.320-324
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• 2008

This study was conducted to investigate abundance of breeding birds in relation to forest environment, to figure out the influential factors in abundance of breeding birds and to get the basic data for effective management of the bird community in Jirisan National Park. For this purpose, this research selected 4 main hiking trails as survey points and conducted a survey on breeding bird species and forest environment from April to August in 2007. The study results are as follows: The number of the birds observed during the breeding season was 33 species at the elevation of 300 meters to 1,900 meters. This research made a regression analysis of 13 bird species appearing at more than 30% of all surveyed points, species richness, and richness in the number of individuals. As a result of making a simple and multiple regression analysis of the factors, among the forest environment factors, that have an effect on richness in bird species, each species was found to be less influenced by an elevation. In addition, this analysis revealed that among the forest environment factors, coverage of tree-1 layer(>12m), tree height, coverage of shrub layer(2${\sim}$0.5m), slope, coverage of subtree-2 layer(4${\sim}$2m) appeared as more influential ones on the variation of abundance in more species than an elevation itself. That explains why it is necessary to continuously maintain and manage the coverage of tree-1 layer(>12m), tree height, coverage of shrub layer(2${\sim}$0.5m), slope, and coverage of subtree-2 layer$(4{\sim}2m)$, etc. for the preservation and management of bird species in a breeding season at Jirisan National Park.

• Korean Journal of Environment and Ecology
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• v.26 no.2
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• pp.186-191
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• 2012

The Chinese Sparrowhawk($Accipiter$ $soloensis$) is the most common breeding raptor in Korea, but its spatial use in the breeding season has been poorly documented. Therefore, to estimate the territory and home range sizes of breeding sparrowhawks, six territorial males(four in 2005 and two in 2006) were observed from June to July in Gyeonggi Province, the Republic of Korea. Main perches, which were used repeatedly(more than three times) or where apparent territorial behaviors were observed, were identified and the locations were analyzed by GIS software. According to the 100% Minimum Convex Polygons which were identified from $25.2{\pm}5.3$ perches, Chinese Sparrowhawks occupied $4.62{\pm}0.90$ ha for breeding territories and used $22.57{\pm}5.12$ ha for their home ranges. These estimates showed larger spatially occupied areas than those in one previous report, but this study suggests that Chinese Sparrowhawks intensively use small areas throughout the breeding season. This result also implies that the sparrowhawks have the potential to be significantly affected by any habitat changes and resource exploitation in the small areas(particularly in small rice paddies of 0.6-2.0 ha) which they largely rely on for food. Although this study was based on observations solely for territory size estimations, this study may be worthwhile as preliminary pilot research for Chinese Sparrowhawk conservation, management, and further studies.

• Korean Journal of Environment and Ecology
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• v.32 no.1
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• pp.39-46
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• 2018

Breeding bird surveys provide the reference information for understanding bird community structure and function in the ecosystem and conserving biodiversity. Recent rapid change of biodiversity due to climate change and other factors has made it necessary to utilize acoustic sensors for accuracy and spatial expansion of forest bird survey data and for time-series monitoring of forest birds. The objective of this study is to investigate the possibility of using acoustic recording sensor to evaluate the diversity of forest birds at breeding season by comparing and analyzing the recorded data of bird songs and field bird survey data. We conducted the site survey and recording in 186 points in 48 areas of 4 regions of Gombaeryeong and Jochimryeong around Jeombongsan Mountain and Jugryeong and Gochiryeong around Sobaeksan Mountain from May 2nd to 16th in 2013. The analysis of the correlation between the recording result and Bird Community Index based on the field survey showed that the number of bird species, population, and the number of bird songs by recording was significantly correlated to the number of species and population by field survey. Moreover, the number of bird species and the number of bird songs by recording showed a significant correlation to species diversity and species richness but no or low significant correlation to species evenness by the field study (observation and listing in parallel). As a result, it was possible to check species composition and species diversity of bird communities by analyzing acoustic recording data on the field. The acoustic recordings of bird songs in the breeding period were more reliable than the non-breeding period in the correlation of recording result and species diversity and for utilization.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.134-134
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• 2022

Mungbean is used for not only seed but sprout, so, consumption of mungbean has been on the rise in Korea. Life cycle of mungbean tends to be short among Legume. For that reason, Mungbean can be harvested for various cropping system and season per regions and farmers regardless of sowing date and harvesting date. So, Prior research is needed about growth characters and life cycle of mungbean per sowing period. Mungebean cultivar 'Dahyun' and 'Sanpo' supplied by Korea Agriculture Technology Promotion Agency(KOAT) is cultivated in wagner pot. Sowing period is proper time of seeding in Jeollanam-do and Gyeongsangnam-do that is major cultivation region of mungbean in korea from early May to mid July every 2 weeks. Length at maturity stage tends to increase from early May(sowing date: 4^th May) to early July(sowing date: 5^th July), but after that, It tends to decrease from mid July(sowing date: 19^th July). Number of branches and nods shows a similar trend. Length of pod has no tendency and no difference per sowing date. Number of pod per plants has also no tendency per sowing date. Test plots sowing in late May has the most number of pods.(Sanpo 22.9pods, Dahyun 16.8) Number of seeds per pod tends to increase to late May and Test plots sowing in mid July has the most number of seed per pod. In case of sowing at early May, Days of emergence is 7d. its summation of temperature is 132.2℃. After that, it tends to decrease to mid June. After mid June, Days of emergence is fixed to 3d. Average temperature growing up in this season, Summation of temperature from sowing to emergence takes the lowest point in test plots sowing in mid June.(Sanpo 88.6℃, Dahyun 88.6) Days of flowering tends to fasten from early May to mid July. Two cultivar shows same level. Days of maturity tends to fasten to mid June, after that tends to slow. In case that many research results about growth characters and life cycle mungbean per sowing period are drawn, it is expected that it result in increase of cultivation area and income of farmer.

• Asian-Australasian Journal of Animal Sciences
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• v.24 no.9
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• pp.1192-1198
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• 2011

Peri-partum metabolic profile was evaluated in winter and summer calving, with 15 Murrah buffaloes in each seasonal group. In summer calvers, significantly lower values were observed for blood plasma urea nitrogen (BUN) at day 30 pre-partum (p<0.05), on calving day (p<0.05) and at all other stages (p<0.01); plasma non-esterified fatty acids (NEFA) values were significantly lower on day 30 pre-partum (p<0.01) and on day 60 post-partum (p<0.05). This was associated with significant reduction in days to first service (DFS) and service per conception (SPC) and an overall better reproductive performance in terms of service period, risk to first service on days 60, 90 and >90, and pregnancy risk to first service up to days 60 and 90. This may be attributed to better pre-partum nutritional status. Cervical and uterine involution were completed in fewer days, involutional changes took place at a faster pace and there were a lower number of abnormal involutional changes in winter compared to summer season. This may be attributed to better post-partum nutrition and less environmental stress. However, validation requires further targeted cohort investigation with a large sample size.

• Journal of Ecology and Environment
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• v.34 no.4
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• pp.357-363
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• 2011

To examine factors affecting feeding efficiency of grey herons (Ardea cinerea), the foraging behavior was studied at a reservoir in Asan city, Chungcheongnam-do, South Korea during the breeding seasons (from April to July) of 2006 and 2007. Four factors (age of foraging birds, time of day, breeding stage, and microhabitat type) were analyzed. Adults were more efficient foragers than recently fledged juveniles, and they had a higher success rate than juveniles. About half of the adults caught large prey, whereas most juveniles caught only small prey. Adult grey herons had different feeding efficiency according to the breeding stage. Pecking and capture rates were high during the late period (fledging stage), and biomass intake rates were high during the early (incubating stage) and late periods. However, time of day had no significant effect on foraging activity of adult grey herons. Feeding activities of adult grey herons also showed significant variation among microhabitat types. Pecking and capture rates were higher in the submerged plants area, but capture success rate and biomass intake rate were not different according to microhabitat type.

• Korean Journal of Breeding Science
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• v.40 no.3
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• pp.336-339
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• 2008

A new spray chrysanthemum cultivar, 'Moon Festival' was released by National Horticultural Research Institute (NHRI), Rural Development Administration (RDA), Korea in 2007. A cross was made in 2002 between '01B1-559', a breeding line of NHRI and 'Baeksokuk', a spray cultivar with white petals. Trials were conducted from 2005 to 2007 for evaluation and selection of this cultivar, including shading culture in summer and retarding culture in autumn. The natural flowering time of "Moon Festival" is late October, but year-round flowering is possible by shading and lighting treatment. The cultivar is semi- double type flowers with light-ivory white petals and green flower center. Flower neck and stem are very hardy. The diameter of flower is 67.5 mm. The number of flowers per stem and petals per flower is 11.5 and 100.5, respectively. The days to flowering under the short day is about 54 in autumn season.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.8_spc
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• pp.1284-1295
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• 2019

Considerable progress in reproduction of dairy goats has been made, with advances in reproductive technology accelerating dairy goat production since the 1980s. Reproduction in goats is described as seasonal. The onset and length of the breeding season is dependent on various factors such as breed, climate, physiological stage, male effect, breeding system, and photoperiod. The reproductive physiology of goats was investigated extensively, including hypothalamic and pituitary control of the ovary related to estrus behavior and cyclicity etc. Photoperiodic treatments coupled with the male effect allow hormone-free synchronization of ovulation, but the kidding rate is still less than for hormonal treatments. Different protocols have been developed to meet the needs and expectations of producers; dairy industries are subject to growing demands for year round production. Hormonal treatments for synchronization of estrus and ovulation in combination with artificial insemination (AI) or natural mating facilitate out-of-season breeding and the grouping of the kidding period. The AI with fresh or frozen semen has been increasingly adopted in the intensive production system, this is perhaps the most powerful tool that reproductive physiologists and geneticists have provided the dairy goat industry with for improving reproductive efficiency, genetic progress and genetic materials transportation. One of the most exciting developments in the reproduction of dairy animals is embryo transfer (ET), the so-called second generation reproductive biotechnology following AI. Multiple ovulation and ET (MOET) program in dairy goats combining with estrus synchronization (ES) and AI significantly increase annual genetic improvement by decreasing the generation interval. Based on the advances in reproduction technologies that have been utilized through experiments and investigation, this review will focus on the application of these technologies and how they can be used to promote the dairy goat research and industry development in the future.

• Korean Journal of Weed Science
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• v.32 no.1
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• pp.17-24
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• 2012

The study was conducted to investigate the effect of weed interference and starter fertilizer on subsequent soybean seed quality at the Agricultural Research Farm and Laboratory of Razi University, Kermanshah, Iran. Two factorial experiment was laid-outon a randomized complete block design with four replications. First factor was starter fertilizer levels (0 and 25 kg $ha^{-1}$) applied in the forms of monoammonium phosphate, the second factor was different weed interference periods consisted of five initial weed-free periods (in which, plots were kept free of weeds for 0, 15, 30, 45 and 60 days after crop emergence (DAE) and then weeds were allowed to grow until harvest) and five initial weed-infested periods (in which, weeds were allowed to grow for 0, 15, 30, 45 and 60DAE, after which the plots were kept free of weeds until harvest). Full season weedy condition reduced 100-seed weight, seed germination percentage and seedling dry weight by 25.9, 13.3 and 22.5%, respectively and increased mean germination time and seed electrical conductivity by 55.8 and 24.3%, respectively as compared with full season weed-free control. However, the traits under study were not significantly influenced when field was kept free of weeds for at least 45 DAE (R1) or weedy condition was continued for less than 30 DAE (V8). There was a significant and negative correlation between weed biomass and seed weight (r = -0.93), so that when weed free condition was less than 45 DAE or weed infested period was continued for at least 30 DAE, soybean plants produced wrinkled and underdeveloped seeds with lower weights and qualities. Moreover, soybean seed quality reduction due to weed interference was more evident when starter fertilizer was applied and weeds interfered with soybean from the beginning of the growing season. Information from the present study is beneficial in soybean seed production systems and where farmers use the harvested seeds for the following planting.