• Title/Summary/Keyword: Physiological Traits

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Evaluation of waterlogging tolerance using chlorophyll fluorescence reaction in the seedlings of Korean ginseng (Panax ginseng C. A. Meyer) accessions (엽록소 형광반응을 이용한 인삼 유전자원의 습해 스트레스 평가)

  • Jee, Moo Geun;Hong, Young Ki;Kim, Sun Ick;Park, Yong Chan;Lee, Ka Soon;Jang, Won Suk;Kwon, A Reum;Seong, Bong Jae;Kim, Me-Sun;Cho, Yong-Gu
    • Journal of Plant Biotechnology
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    • v.49 no.3
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    • pp.240-249
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    • 2022
  • Measuring chlorophyll fluorescence (CF) is a useful tool for assessing a plant's ability to tolerate abiotic stresses such as drought, waterlogging and high temperature. Korean ginseng is highly sensitive to water stress in paddy fields. To evaluate the possibility of non-destructively diagnosing waterlogging stress using chlorophyll fluorescence (CF) imaging techniques, we screened 57 ginseng accessions for waterlogging tolerance. To evaluate waterlogging tolerance among the 2-year-old Korean ginseng accessions, we treated ginseng plants with water stress for 25 days. The physiological disorder rate was characterized through visual assessment (an assigned score of 0-5). The physiological disorder rates of Geumjin, Geumsun and GS00-58 were lower than that of other accessions. In contrast, lines GS97-62, GS97-69 and GS98-1-5 were deemed susceptible. Root traits, chlorophyll content and the reduction rates decreased in most ginseng accessions. Further, these metrics were significantly lower in susceptible genotypes compared to resistant ones. All CF parameters showed a positive or negative response to waterlogging stress, and this response continuously increased over the treatment time among the genotypes. The CF parameter Fv/Fm was used to screen the 57 accessions, and the results showed clear differences in Fv/Fm between the susceptible and resistant genotypes. Susceptible genotypes had an especially low Fv/Fm value of less than 0.8, reflecting damage to the reaction center of photosystem II. It is concluded that Fv/Fm can be used as a CF parameter index for screening waterlogging stress tolerance in ginseng genotypes.

NO2 and SO2 Reduction Capacities and Their Relation to Leaf Physiological and Morphological Traits in Ten Landscaping Tree Species (조경수 10개 수종에 있어 NO2, SO2 저감 능력과 잎의 생리적, 형태적 특성과의 관계)

  • Kim, Kunhyo;Jeon, Jihyeon;Yun, Chan Ju;Kim, Tae Kyung;Hong, Jeonghyun;Jeon, Gi-Seong;Kim, Hyun Seok
    • Journal of Korean Society of Forest Science
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    • v.110 no.3
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    • pp.393-405
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    • 2021
  • With increasing anthropogenic emission sources, air pollutants are emerging as a severe environmental problem worldwide. Accordingly, the importance of landscape trees is emerging as a potential solution to reduce air pollutants, especially in urban areas. This study quantified and compared NO2 and SO2 reduction abilities of ten major landscape tree species and analyzed the relationship between reduction ability and physiological and morphological characteristics. The results showed NO2 reduction per leaf area was greatest in Cornus officinalis (19.81 ± 3.84 ng cm-2 hr-1) and lowest in Pinus strobus (1.51 ± 0.81 ng cm-2 hr-1). In addition, NO2 reduction by broadleaf species (14.72 ± 1.32 ng cm-2 hr-1) was 3.1-times greater than needleleaf species (4.68 ± 1.26 ng cm-2hr-1; P < 0.001). Further, SO2 reduction per leaf area was greatest in Zelkova serrata (70.04 ± 7.74 ng cm-2 hr-1) and lowest in Pinus strobus (4.79 ± 1.02 ng cm-2 hr-1). Similarly, SO2 reduction by broadleaf species (44.21 ± 5.01 ng cm-2 hr-1) was 3.9-times greater than needleleaf species (11.47 ± 3.03 ng cm-2 hr-1; P < 0.001). Correlation analysis revealed differences in NO2 reduction was best explained by chlorophyll b content (R2 = 0.671, P = 0.003) and SO2 reduction was best described by SLA and length of margin per leaf area (R2 = 0.456, P = 0.032 and R2 = 0.437, P = 0.001, R2 = 0.872, P < 0.001, respectively). In summary, the ability of trees to reduce air pollutants was related to photosynthesis, evapotranspiration, stomatal conductance, and leaf thickness. These findings highlight effective reduction of air pollutants by landscaping trees requires comprehensively analyzing physiological and morphological species characteristics.

Effects of Genetic, Physiological, and Other Variations on Yolk Cholesterol Level (난황 콜레스테롤 수준에 미치는 유전적, 생리적 및 기타 변이 요인들의 효과)

  • Y. O. Suk;K. W. Washburn
    • Korean Journal of Poultry Science
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    • v.24 no.4
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    • pp.169-177
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    • 1997
  • Four experiments were conducted to investigate the association of yolk cholesterol level with egg trails, serum cholesterol level, body weight (BW) and breed differences and other variations. Athens Canadian Randombred (ACRB), a commercial layer breed (CL) and two commercial broiler breeds (BR1 and BR2) were used for this studies. Egg weight of CL was heavier by 8.7g per egg than that of ACRB, but the yolk percentage and yolk cholesterol were lower by 7.8% per egg and 5.5mg per g yolk than those of ACRB, respectively. Yolk cholesterol content had no significant relation with the average egg weight or yolk weight in ACRB, but was significantly related with yolk fat level. However, yolk cholesterol level in CL showed inverse relationship with other egg traits compared to that of ACRB. In the CL female group, the association of yolk cholesterol level with BW was significant(P$\leq$0.05) at 25 weeks of age, but was not significant different at 26 wks of age. The relationship of yolk cholesterol with serum was not significantly different at 25 weeks of age, whereas it showed significant negative(-) correlation coefficient(P$\leq$0.01) at 26 wks of age. The association of yolk cholesterol level with egg age in CL population was not high comared to that of other treatments. The serum cholesterol content of CL was not significantly different with BR1 and BR2 populations at 25 weeks of age, but was significantly(P$\leq$0.05) higher than that of BR1 or BR2 at 26 weeks old.

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Production Traits and Stress Responses of Five Korean Native Chicken Breeds (한국토종닭 5품종의 생산능력 및 스트레스 반응 정도)

  • Cho, Eun Jung;Choi, Eun Sik;Jeong, Hyeon Cheol;Kim, Bo Kyung;Sohn, Sea Hwan
    • Korean Journal of Poultry Science
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    • v.47 no.2
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    • pp.95-105
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    • 2020
  • This study presents the production characteristics and physiological characteristics of five Korean native chicken (KNC) breeds consisting of Hwanggalsaek Jaeraejong (HJ), Korean Rhode Island Red (KR), Korean White Leghorn (KL), Korean Brown Cornish (KC), and Korean Ogye (KO). We investigated their production performances, vitalities, and stress responses. We measured the survival rate, body weight, age at first egg-laying, hen-day egg production, egg weight, amount of telomeric DNA, heterophil-lymphocyte ratio (H/L ratio), and heat shock protein (HSP)-70, HSP-90α and HSP-90β gene expression levels for 493 KNCs. The survival rate was highest in KR, and lowest in KO. Body weights were steadily high in the order of KC, KR, HJ, KO and KL. Average hen-day egg production was highest in KL, and lowest in KC. While the amount of telomeric DNA was highest in KR, and lowest in KC. Furthermore, both the H/L ratio and the HSP-90β gene expression level were highest in KC, and lowest in KR. These results indicated that the KR breed was highly resistant to stress, whereas KC was more susceptible to stress. Taken together, it is considered that with improvements the KC breed would be more suited to be used as a Korean broiler breed while KL would be more appropriately used as a Korean layer breed. In addition, it is considered that the KR breed is appropriate to be used as a maternal chicken breeder based on good production capacity and excellent robustness, while the HJ breed is desirable to be improved as a high-quality Korean meat breed based on its excellent meat quality.

The Characteristics of Heavy Metal Distributions in the Tissues of Feral Pigeon (Columba livia) as a Bio-monitoring Indicator (환경오염 지표종인 집비둘기의 생체조직 내 중금속 분포 특성)

  • Lee, Jangho;Lee, Jongchun;Park, Jong-Hyouk;Lee, Eugene;Shim, Kyuyoung;Jang, Heeyeon;Kim, Myungjin
    • Journal of Environmental Impact Assessment
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    • v.25 no.6
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    • pp.502-513
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    • 2016
  • In this study, heavy metal distributions in the tissues of feral pigeon (Columba livia) were characterized using samples collected from bio-monitoring sites (Hangang Park and Hampyeong Park) of the NESB (National Environmental Specimen Bank), Korea, in order to evaluate the feasibility of feral pigeons as an indicator for the environmental monitoring. Cadmium (Cd) was analyzed to be accumulated in kidneys at higher concentration than in the other tissues. Such trend can also be found in the reviews on the Cd accumulations of the 34 cases including 17 avian species which showed that 31 cases had the highest Cd concentrations in the kidney among tissues. However, lead (Pb) was found to be richest in the bones in this study. 17 cases out of 30 reviewed cases had the highest Pb concentration in bones, whereas other 10 cases showed the highest concentration in kidneys, and 3 cases in livers. Therefore, kidneys together with bones can be a main target organ to test cadmium exposure to different habitat environments depending on physiological traits of birds. Zinc (Zn) was found to be the highest concentration in the pigeon livers of Hangang Park, but not in the bones. In contrast, the 13 cases of 16 reviewed cases had the highest Zn concentration in bones, and the 3 cases in livers. In addition, the heavy metal distribution patterns in relations to the metal accumulation mechanisms (a competition between Pb and Ca, a function of methallothionein protein, and etc.) were discussed.

Analysis of Hematologic Characteristics of Endangered Korean Native Cattle according to the Age (성장단계별 멸종위기 희소한우의 혈액학적 특성분석)

  • Kim, Hyun;Ko, Yeoung-Gyu;Kim, Nam-Tae;Choe, Changyong;Seong, Hwan-Hoo
    • Reproductive and Developmental Biology
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    • v.39 no.1
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    • pp.13-21
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    • 2015
  • The importance of genetic resource preservation has been highlighted in the literature as a means of maintaining genetic diversity. Investigations for hematologic values and the differential count of white blood cell count (WBC) for Korean indigenous cattle (KIC) and endangered indigenous cattle (EIC) are rarely performed. Therefore, the objective of this study was to investigate the hematologic values of total 40 EIC (White, Black, Mini cattle) and 35 KIC as control by analysis of hematologic characteristics. As a result, the mean values of RBC and platelet of EIC were significantly decreased by age (p<0.05). The mean values of RBC, HCT, MCV and MCHC between EIC and KIC of the same age (2~3 years) showed the statistical significance (p<0.05). Also, in the WBC of EIC, the mean values were decreased according to the age from $13.9{\times}10^3/{\mu}L{\sim}12.7{\times}10^3/{\mu}L$ under 1 year to $9.1{\times}10^3/{\mu}L{\sim}11.5{\times}10^3/{\mu}L$ over 2 years respectively. In the differential count of WBC of EIC (White, Black, Mini cattle), it showed generally the rates of 40.2%, 52.2%, 49.0% lymphocyte and 27.2%, 33.9%, 32.0% segmented neutrophil from 2~3 years respectively. Result of this study will be used for establishing reference range for blood analysis in EIC such as white, black and mini cattle. This study reported hematological values which could serve as baseline information for comparison in conditions of nutrient deficiency, physiological and health status of endangered Korean native cattle. In addition, this study provides a valuable resource for further investigations of the preservation of rare genetic stocks underlying traits of interest in cattle.

Effects of a Growth Retardant Paclobutrazol on the Growth and Yield Related Elements of Peanut (Archis hypogea L.) (생장조정제(生長調整劑) Paclobutrazol이 땅콩의 생육특성(生育特性)과 수량관련요소(收量關聯要素)에 미치는 영향(影響))

  • Lee, H.S.;Cho, J.S.
    • Korean Journal of Weed Science
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    • v.8 no.1
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    • pp.71-89
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    • 1988
  • This study was conducted to evaluate the effect of a growth retardant, Paclobutrazol on the growth, yield and its components. and physiological traits in peanut cv. Saeddle (early variety) and Nampung (medium variety). The results are summarized as follows : Main stem and branch length of both varieties were remarkably retarded at early growth stage application, but the retardation effect was reduced at late growth stage application. Number of branches was increased remarkably by treating 60ppm at 20days after seedling (DAS) in early variety. Lodging ill medium variety was not observed through growth period when 120ppm of Paclobutrazol was applied while lodging was not appeared between 40 DAS and 80 DAS in early variety. The numbers of riped pods in early variety was increased when application of 120ppm at 40 DAS was made while it was increased as application of 120ppm at 90 DAS in the medium variety. Cercospora leaf spot was reduced by spraying at 40 or 50 DAS regardless of concentration and varieties. Chlorophyll content and photosynthetic activity increased when paclobutrazol was applied during 40-60 DAS in early variety while these were observed at 90 DAS in medium variety. Seed weight tended to increase as paclobutrazol application was delayed. The ratio of pods to seeds was higher at 60ppm-40 DAS in early variety while it was higher at 120ppm-90 DAS in medium variety.

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Current Statues of Phenomics and its Application for Crop Improvement: Imaging Systems for High-throughput Screening (작물육종 효율 극대화를 위한 피노믹스(phenomics) 연구동향: 화상기술을 이용한 식물 표현형 분석을 중심으로)

  • Lee, Seong-Kon;Kwon, Tack-Ryoun;Suh, Eun-Jung;Bae, Shin-Chul
    • Korean Journal of Breeding Science
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    • v.43 no.4
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    • pp.233-240
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    • 2011
  • Food security has been a main global issue due to climate changes and growing world population expected to 9 billion by 2050. While biodiversity is becoming more highlight, breeders are confronting shortage of various genetic materials needed for new variety to tackle food shortage challenge. Though biotechnology is still under debate on potential risk to human and environment, it is considered as one of alternative tools to address food supply issue for its potential to create a number of variations in genetic resource. The new technology, phenomics, is developing to improve efficiency of crop improvement. Phenomics is concerned with the measurement of phenomes which are the physical, morphological, physiological and/or biochemical traits of organisms as they change in response to genetic mutation and environmental influences. It can be served to provide better understanding of phenotypes at whole plant. For last decades, high-throughput screening (HTS) systems have been developed to measure phenomes, rapidly and quantitatively. Imaging technology such as thermal and chlorophyll fluorescence imaging systems is an area of HTS which has been used in agriculture. In this article, we review the current statues of high-throughput screening system in phenomics and its application for crop improvement.

Studies on the Meat Production and Woolskin Processing of Sheep and Korean Native Goats for Increasing Farm Income as a Family Subsidiary Work (농가부업(農家副業)의 소득향상(所得向上)을 위한 양육생산(羊肉生産) 및 모피가공(毛皮加工)에 관(關)한 연구(硏究))

  • Kwon, Soon-Ki;Kim, Jong-Woo;Han, Sung-Wook;Lee, Kyu Seung
    • Korean Journal of Agricultural Science
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    • v.5 no.2
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    • pp.93-114
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    • 1978
  • The purpose of the study was to find out possible ways for increasing farm income through the sheep and Korean native goats farming, and to investigate meat productivity, wool productivity; woolskin utility, physiological characteristics and correlation between economical college animal farm of the Chungnam National University and sample farms in the suburbs of Dae jeon City were selected for feeding 20 heads of Corriedale wethers and another 20 heads Korean native kids as research materials for the periods of 5th May-26th November, 1977. The data such as growth rate, carcass, viscera weight, blood picture and plamsa components, hebage intake and economic traits were obtained and analysed. The result of the study are summarized as follows: 1. Meat production and quality 1) After 196days of feeding, the body weight of sheep and Korean native goats was increased by two times of those at the beginning of the trial, i.e. 20kg and 8kg respectively. 2) There was no significance of growth rates of sheep in housing and grazing. 3) The growth rate of Korean native goats were excellent at the mountainous areas of Gong ju-Gun where infectious diseases were not found 4) Accroding to the body measurements of 18-month-old sheep, percentages of hip height, body length, rump length, chest depth, chest width, hip width, chest girth and forearm circumference to the withers height were 103,%, 104%, 33%, 44%, 31%, 23%, 135% and 15% respectively, and those of hip height, body length, chest depth and chest girth of 8-month-old native goats to the withers height were 106%, 109%, 46% and 122,% respecitively. As a result, it was found that the percentage of hip height, body length and chest depth of Korean native goats were higher than those of sheep while that of the chest girth of goats was lower. 5) In the carcass data, 47, $52{\pm}2.27%$ of carcass percentage, $34.61{\pm}1.62%$ of lean meat, $26.07{\pm}2.51%$ of viscera, $9.75{\pm}1.4%$ of bone, and $20.95%{\pm}2.14%$ of woolskin for sheep, and $45.58{\pm}5.63%$ of carcass percentage, $27.62{\p}3.81%$ of meat, $34.86{\pm}4.16%$ of viscera, $11.66{\pm}1.83%$ of bone, $3.63{\pm}1.61%$ of skull and $9.26{\pm}2.41%$ of woolskin for native goats were obtained. 6) The contents of moisture, crude protein, crude fat and crude ash in native goat meat were much similar in both plots of housing and grazing. It was, however, known that the contents of moisture and protein were higher in grazinrg than in housing, while fat content was lower in grazing plots. 7) The weights of visceral organs shown similar tendency for both of sheep and native goats. For the weights of liver, heart, kidney and spleen, significance was not reconized among the treatments. Those of rumen, reticulum, small and large intestine were heavier in grazing than in housing, while the amount of visceral fat was heavier in housing. 2. Wool productivity and woolskin 1) The wool production of sheep for 7 months was $3.88{\pm}1.02kg$, and wool percentage, staple length, straighten length, wool growth per day and number of crimps were $9.27{\pm}1.48%$, 8. $47{\pm}1.00cm$, $10.63{\pm}0.99cm$, $0.40{\pm}0.04cm$ and $2.78{\pm}0.40$ respecitively. 2) The tensile strength and tear strength of woolskin treated by alum tanning were highest on the skin obtained from rump, i.e. $1,351kg/mm^2$ and $2,252kg/mm^2$ respectively, and they are in order of loin and shoulder. 3. Utilization and improvement of pasture. 1) The difference of herbage intake of native goats was not recognized between grazing and tethering, but the intake in the afternoon was s lightly higher than that in the morning. However the hervage intake of sheep was superior in grazing and in the afternoon. 2) The cultivation effect was lower in the native goat plots due to their cultivation abilities, in other words, the establishment rates of pasture by hoof cultivation were 60.25% in the goat plots and 77.35% in the sheep plots. 4. Correlation among economical traits. 1) The correlation between live weight of sheep and daily gain was higher. On the other hand, the correlation between other traits was not significant except that live weight, daily gain and lean meat percentage to the length of thoracic vertebrae. The live weight of native goats and meat production were highly correlated, and high correlation was also found between weights of carcass and meat. However, negative correlation was shown between viscera weight and live weight as well as daily gain. 2) The correlatoin between fleece weight of sheep and other traits such as live weight, daily gain and fleece percentage is very high at the 1% siginficant level, and this means that rapid-growth individuals can produce much fleece. 3) The correlation between the factors such as weights of live body, lean meat and viscera of sheep and body measurements, i. e. chest girth and body length was highest, and weights, of carcass and lean meat was highly correlated to chest width and depth. It will be therefore reasonable that the meat productivity estimates will have to be made on the basis of chest girth and body length. The meat production traits of native goats were highly correlated to the most of body measurement data, and the correlation coefficient between chest girth and weights of live body, carcass, lean meat and bone percentage was very high, i. e. 0.992-0.974 in particular. The correlations of meat production traits to chest depth, forearm circumference, body length were 0.759-0.911, 0.759-0.909 and 0.708-0.872 respectively. Therefore, the meat production of native goats will have to be estimated on the basis of chest data. 5. Blood picture and plasma components. 1) The number of erythrocyte and MCHC of native goats were $12.93{\times}10^6/mm^3$ and 36.14%, and those of sheep were $10.68{\times}10^6/mm^3$ and 36.26 respectively. The values of native goats were significantly higher than those of sheep. 2) The hemoglobin concentration, PVC, MCV and MCR of native goats were 10.92 g/100ml, $23.40{\mu}^3$ and 10.94 pg, and those of sheep were 11.73 g/100ml, 36.25 ml/100ml, $33.97{\mu}^3$ and 30.2 ml/100ml 8.43 pg respectively. The values of native goats were significantly lower those of sheep. 3) The number of leukocytes of native goats was significantly higher than that of sheep, that is, $11.64{\times}10^3/mm^3$ in native goats and $9.32{\times}10^3/mm^3$ in sheep. 4) In differential count of leukocyte, neutrophil was significantly high in native goats while lympocyte in sheep. On the other hand, the basophil, eosinophil and monocyte were not significant between native goats and sheep. 5) The amounts of total protein and glucose in the plasma of native goats were 6.2g/100ml and 53.6mg/100ml, and those of sheep were 5.6g/100ml and 45.7mg/100ml, which means that the values of native goats were significantly higher that those of sheep. The amount of total-lipid of native goats(127.6mg/100ml) was significantly than that of sheep(149.6mg/100ml). 6) The amount of non-protein nitrogen, cholesterol, Ca, P, K, Na and Cl were not different between native goats and sheep. 6. Economic analysis. 1) The gross revenue of a farm which fed native goats and sheep was 4,000won per head and the optimum size for feeding them in a farm as a subsidiary work is 5-10 heads. 2) Since there was no difference between housing and grazing, they can be fed in group for farm's subsidiary work. 3) They can be also fed by youths and house wives in the suburbs of cities, because labour requirement is estimated as only two hours per days for feeding 5 heads of native goats and sheep.

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Meteorological Constraints and Countermeasures in Rice Breeding -Breeding for cold tolerance- (기상재해와 수도육종상의 대책 - 내냉성품종육성방안-)

  • Mun-Hue Heu;Young-Soo Han
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.27 no.4
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    • pp.371-384
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    • 1982
  • Highly cold tolerant varieties are requested not only at high latitute cool area but also tropical high elevated areas, and the required tolerance is different from location to location. IRRI identified 6 different types of cold tolerance required in the world for breeding purpose; a) Hokkaido type, b) Suweon type, c) Taipei 1st season type, d) Taipei 2nd season type, e) Tropical alpine type and, f) Bangladesh type. The cold tolerance requested in Korea is more eargent in Tongil group cultivars and their required tolerance is the one such as the physiological activities at low temperature are as active as in Japonica group cultivars at least during young seedling stage and reproduction stage. With conventional Japonica cultivars, such cold tolerant characters are requested as short growth duration but stable basic vegetative growth, less sensitive to high temperature and less prolonged growth duration at low temperature. The methods screening for cold tolerance were developed rapidly after the Tongil cultivar was reliesed. The facilities of screening for cold tolerance, such as, low temperature incubator, cold water tank, growth cabinet, phytotron, cold water nursery in Chuncheon, breeding nursery located in Jinbu, Unbong and Youngduk, are well established. Foreign facilities such as, cold water tank with the rapid generation advancement facilities, cold nurseries located in Banaue, Kathmandu and Kashimir may be available for the screening of some limitted breeding materials. For the reference, screening methods applied at different growth stages in Japan are introduced. The component characters of cold tolerance are not well identified, but the varietal differences in a) germinability, b) young seedling growth, c) rooting, d) tillering, e) discolation, f) nutrition uptake, g) photosynthesis rate, h) delay in heading, i) pollen sterility, and j) grain fertility at low temperature are reported to be distinguishable. Relationships among those traits are not consistent. Reported studies on the inheritance of cold tolerance are summarized. Four or more genes are controlling low temperature germinability, one or several genes are controlling seedling tolerance, and four or more genes are responsible for the pollen fertility of the rice treated with cold air or grown in the cold water nursery. But most of those data indicate that the results may come out in different way if those were tested at different temperature. Many cold tolerant parents among Japonicas, Indicas and Javanicas were identified as the results of the improvement of cold tolerance screening techniques and IRTP efforts and they are ready to be utilized. Considering a) diversification of germ plasm, b) integration of resistances to diseases and insects, c) identification of adaptability of recommending cultivars and, d) systematic control of recommending cultivars, breeding strategies for short term and long term are suggested. For short term, efforts will be concentrated mainly to the conventional cultivar group. Domestic cultivars will be used as foundation stock and ecologically different foreign introductions such as from Hokkaido, China or from Taiwan, will be used as cross parents for the adjustment of growth durations and synthsize the prototype of tolerances. While at the other side, extreme early waxy Japonicas will be crossed with the Indica parents which are identified for their resistances to the diseases and insects. Through the back corsses to waxy Japonicas, those Indica resistances will be transfered to the Japonicas and these will be utilized to the crosses for the improvement of resistances of prototype. For the long term, efforts will be payed to synthsize all the available tolerances identified any from Japonicas, Indicas and Javanicas to diversify the germ plasm. The tolerant cultivars newly synthsized, should be stable and affected minimum. to the low temperature at all the growing stages. The resistances to the diseases and insects should be integrated also. The rapid generation advancement, pollen culture and international cooperations were emphasized to maximize the breeding efficiency.

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