• Title/Summary/Keyword: cold shortening

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Effect of Antioxidant Fortification on Preservability of Buffalo Semen

  • Raina, V.S.;Gupta, A.K.;Singh, Kiran
    • Asian-Australasian Journal of Animal Sciences
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    • v.15 no.1
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    • pp.16-18
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    • 2002
  • During the process of freezing, spermatozoa suffer cold shock which increases their susceptibility to lipid peroxidation which plays an important role in ageing of spermatozoa, shortening their life span and affecting the preservation of semen. An experiment was therefore conducted to study the effect of addition of natural antioxidants into semen diluents on the preservability of buffalo semen. Split semen samples were extended in milk egg yolk diluents fortified with vitamin E (MYE), vitamin C (MYC) and control group (MYO); Tris-egg yolk diluents fortified with vitamin E (TYE), vitamin C (TYC) and control group (TYO) and evaluated for their preservabilities at 4-7$^{\circ}C$ and $37^{\circ}C$. Overall least squares mean of percent motility observed after 0, 24, 48, 72 and 96 h of preservation at 4-7$^{\circ}C$ were 66.70, 54.00, 36.80, 21.90 and 12.50, respectively while the estimates for semen extended in MYE, MYC, MYO, TYE, TYC and TYO were 44.80, 42.70, 38.70, 36.00, 35.20 and 33.00 percent, respectively. The results showed that motility was significantly (p<0.01) affected by extender (extender-antioxidant combination) and preservation interval. Overall least squares mean percent motility observed after 0, 4, 8, 12 and 24 h of preservation at $37^{\circ}C$ were 68.50, 58.90, 45.00, 38.10 and 18.10 percent, respectively, while the estimates for semen extended in MYE, MYC, MYO, TYE, TYC and TYO were 48.20, 49.30, 46.80, 45.30, 42.30 and 42.50 percent, respectively. Extender and storage interval were found to be significantly (p<0.01) affecting spermatozoa motility on room temperature preservation. The results indicated that the incorporation of antioxidants, especially vitamin E, had beneficial effect on preservability of buffalo semen.

Microsurgical Replantation of Very Distally Amputated Finger (수지 첨부 절단의 재접합술)

  • Kang, Hong-Dae;Kim, Johng-Jin;Lee, Nae-Ho;Yang, Kyung-Moo;Moon, Ji-Hyun
    • Archives of Reconstructive Microsurgery
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    • v.16 no.2
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    • pp.75-81
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    • 2007
  • Introduction: Microsurgical replantation of amputated digit have become common procedure in recent years. However replantation of fingertip amputation, Zone I by Yamano classification, is still difficult because digital arteries branch into small arteries and also digital veins are hard to separate from the immobile soft tissue. So, fingertip amputation was covered by volar V-Y flap, composite graft, cross finger flap and groin flap. But patients who have been treated by these methods experience shortening of digit, nail deformity, excessive tenderness and persistent pain. Replantation could solve most of these problems. Material & Methods: In our department, from March 2004 to August 2007, 36 digits in 32 patients with complete amputation at distal to nail base were replanted using a microsurgical technique. Results: The overall survival rate of the replanted finger was 75%. Venous anastomosis was possible in 8 cases and impossible in 28 cases. In latter cases external bleeding technique was applied with medical leech. Conclusion: After replantation, a few patient complained decreased sensibility, nail deformity and cold intolerance. But most of patients were satisfied with the functional and cosmetic appearance of the viable replanted digits. We believe the replantation should be the first choice in fingertip amputation.

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Use of Intermittent Antegrade Warm Blood Cardioplegia in CABG (관상동맥 우회로조성술에서 간헐적 전방 온혈 심정지액의 이용)

  • 김정택;백완기;김영삼;윤용한;김혜숙;이춘수;임현경;김현태;김광호
    • Journal of Chest Surgery
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    • v.36 no.11
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    • pp.828-833
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    • 2003
  • Background: It has been reported that the recently developed intermittent antegrade warm blood cardioplegia (IAWBC) has better myocardial protective effects during coronary artery bypass surgery than cold blood cardioplegia or continuos retrograde cold blood cardioplegia. The aim of this study is to evaluate the safety and usefulness of IAWBC by comparing it retrospectively with intermittent retrograde cold blood cardioplegia (lRCBC). Material and Method: From April 2001 to Feb. 2003, fifty seven patients who underwent isolated coronary surgery were divided into two groups (IAWBC vs. IRCBC). The two group had similar demographic and angiographic characteristics. There were no statistical differences in age, sex, Canadian Cardiovascular Society Functional Classification for angina, ejection fraction, and number of grafts. Result: Aortic cross clamping time and total pump time in IAWBC (99$\pm$23 and vs. 126$\pm$32 min) were shorter than those of IRCBC (118$\pm$32 min. and 185$\pm$48 min.)(p<0.05). The reperfusion time (13$\pm$7 min) in IAWBC was shorter than that of IRCBC (62$\pm$109 min.)(p<0.05). CKMB at 12 hours and 24 hours (16$\pm$15 and 9$\pm$13) in IAWBC was lower than that of IRCBC (33$\pm$47 and 17$\pm$26)(p<0.05). The awakening time in IAWBC (2$\pm$1 hour) was shorter than that of IRCBC (4$\pm$3)(p<0.05). The number of spontaneous heart beat recovery in IAWBC (85%) was more than that of IRCBC (35%)(p<0.05). The cardiac index after discontinuing cardio-pulmonary bypass was significantly elevated in the IAWBC group. The prevalence of perioperative myocardial infarction in IAWBC (4%) was lower than that of IRCBC group (20%)(p<0.05). Conclusion: Intermittent antegrade warm blood cardioplegia is a safe, reliable, and effective technique for myocardial protection. It can also provide simpler and economic way than the retrograde cold cardioplegia by shortening of cardiopulmonary bypass time and avoiding retrograde cannulation for coronary sinus.

Egg-forming and Preservation Methods of the Emma Field Cricket Eggs, Teleogrylius emma (Orthoptera: Gryllidae) (왕귀뚜라미(Teleogryiius emma)알의 실내 인공 채란 및 저장)

  • Kim Namjung;Hong Seong-Jin;Seol Kwang-Youl;Kwon Ohseok;Kim Seong-Hyun
    • Korean journal of applied entomology
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    • v.44 no.1 s.138
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    • pp.61-65
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    • 2005
  • Egg-forming and preservation methods for the indoor-rearing system of the emma field cricket, Teleogryllus emma, were investigated. The oviposition preference experiment on different mats, soil(natural oviposition mat) and $oasis^{\circledR}$(artificial oviposition mat), showed that T. emma preferred to oviposit on the $oasis^{\circledR}$. On the other hand, $oasis^{\circledR}$ had more inactive number of eggs laid per female and hatchability than another. However, the number of eggs laid per female and hatchability within 50 days after emergence were better than soil. The experiment on the hatching of the eggs showed that eggs could be stocked at $10^{\circ}C$ for 40 days with 14 day pre-period after laying, representing $62.1\%$ hatchability, when considering generation shortening. On the other hand, When it had been kept in cold storage for 90 days at $7.5^{\circ}C$ with 14 day pre-period after laying it, appeared to be the most suitable for long period-storage method by hatchability $65.1\%$.

Post-slaughter Intervention Techniques to Ensure Tenderness of Beef Muscles for Korean Consumers (한국 소비자 쇠고기 연도 보증을 위한 도축후 도체 처리기술)

  • 황인호
    • Journal of Animal Science and Technology
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    • v.48 no.6
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    • pp.921-932
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    • 2006
  • Management to improve beef tenderness is always been a historical idea, but during the recent past it has become an issue of prime importance to the meat scientists and the industries as well. Variation in tenderness is the prime explanation for consumer’s dissatisfaction for the concern meat. It has been well documented that both postmortem proteolysis and sarcomere length have significant effect on meat tenderness and its consistency. Electrical stimulation and tenderstretch techniques have been used by a number of countries to underpin carcass quality assurance schemes focused on eating quality. The mechanism(s) by which the postmortem interventions improve tenderness (or prevent toughness) has not been fully elucidated. However, it is evident that electrical stimulation accelerates the development of rigor mortis so that prevention of cold shortening is possible and ageing commences at higher temperatures. On the other hand, tendersretch appears to prevent meat toughness via placing tension of the myofibrils and connective matrix during rigor development. Previous findings indicated that electrical stimulation and tenderstretch improved beef tenderness even for fattened cattle under moderate chilling conditions. Recent studies demonstrate beef tenderness to be one of the most important factors determining satisfaction levels of Korean beef consumers. There are number of studies which reported that electrical stimulation and tenderstretch techniques improved Hanwoo tenderness and color. It is believed that the techniques are mostly useful wherein controls of carcass size, fatness and/or chilling regimes are not easy such as Korean beef industry. However, Korean beef industry is one such area where postmortem intervention techniques have not been adopted so far. Taking into consideration of the Korean beef industry, wherein carcass size and fatness varies the post-slaughter intervention technique could be the most feasible measurement to ensure eating quality. The manuscript attempts to highlight the current knowledge aiming primarily towards the assurance of beef tenderness.

Growth and Dry Matter Accumulation in Different Ecotypes of Soybeans (Glycine max. L.) (생태형이 다른 대두품종의 생육 및 건물축적)

  • 정길웅
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.33 no.2
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    • pp.174-181
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    • 1988
  • A comparison was made the differences of growth and some yield components of two soybean ecotypes (summer and two autumn types) at different planting dates (15 April, 15 May, and 15 June) and also made the different patterns of dry matter accumulation of one summer type and two autumn types of soybeans at Agricultural Experiment Farm, College of Agriculture, Dankook University, Cheonan City, in 1987. [Planting date experiment] Days to emergence of four varieties were observed no difference. and, therefore, it was speculated that field observation of the difference of cold tolerence between varieties was difficult. Shortening rate of flowering clays as planting dates delayed was no different between two ecotypes, summer vs. autumn types of soybean. Summer types, DN82029-3 and ES18085-1, were observed not greater difference of days to maturity between early and late planting dates as compared with that of autumn types, Changyeobkong and Paldalkong. At late planting, summer types were observed more to hasten days to ripening due to high temperature in late growing season than that of autumn types. This caused to decrease somewhat greater rate of some yield componments, and finally yield as planting date delayed. As compared to autumn types, summer types, DN82029-3 and ES18085-1 showed longer stem height and lower airdry weight at late planting. [Dry matter accumulation pattern] Stem elongation after flowering of three varieties, DN82029-3, Changyeobkong and Danyeobkong, ranged 17 to 32 cm and increment of leaf area index 0.83-1.53. DN82029-3 reached 49 days faster in maximum total dry weight than that of autumn types, Changyeobkong and Danyeobkong. However. maximum total dry weight of DN82029-3 showed 50% to autumn types. At 15 May planting, summer type, day-neutrality, transfered faster into reproductive growth phase without enough growth of vegetative growth and also hastened ripening days, and thus lower dry matter accumulation and finally lower yield.

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The Influence of Vacuum Packaging of Hot-Boned Lamb at Early Postmortem Time on Meat Quality during Postmortem Chilled Storage

  • Zhao, Yingxin;Chen, Li;Bruce, Heather L.;Wang, Zhenyu;Roy, Bimol C.;Li, Xin;Zhang, Dequan;Yang, Wei;Hou, Chengli
    • Food Science of Animal Resources
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    • v.42 no.5
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    • pp.816-832
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    • 2022
  • To evaluate the effects of early postmortem vacuum packaging (VP) on meat quality during postmortem chilled storage, hot-boned lamb was vacuum-packaged at 1, 6, 12, 24, and 48 h postmortem and stored around 2℃ until 168 h postmortem, with lamb packaged in plastic wrap as the control (aerobic packaging). Intramuscular pH decline was delayed when lamb was vacuum packaged at 1, 6, and 12 h postmortem (p<0.05). The lamb vacuum-packaged at 1 h postmortem (VP-1h group) had significantly lower shear force values and purge losses accompanied by lower free thiol group values than other treatments during postmortem storage and was also higher in extractable calpain-1 activity by 6 h postmortem (p<0.05). Free thiol group concentrations were significantly higher after VP at 6 and 12 h postmortem (p<0.05). Packaging lamb under vacuum very early postmortem produced the lowest shear force and purge loss, likely by slowing heat loss and muscle temperature decline, implying that lamb quality is improved by VP when applied very early postmortem. This was at the expense of protein oxidation, which was unrelated to other meat quality measurements, most likely because potential contracture during hot boning confounded its impact. Further research is required to understand the implications of the interaction between protein oxidation, VP, and hot boning on the acceptability of lamb.

The Evaluation of Usefulness of Pixelated Breast-Specific Gamma Imaging in Thyroid scan (Pixelated Breast-Specific Gamma Imaging(BSGI) 감마 카메라를 이용한 갑상선 검사의 유용성 평가)

  • Jung, Eun-Mi;Seong, Ji-Hye;Yoo, Hee-Jae
    • The Korean Journal of Nuclear Medicine Technology
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    • v.15 no.1
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    • pp.90-93
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    • 2011
  • Purpose: A Pixelated BSGI gamma camera has features to enhance resolution and sensitivity and minimize the distance between detector and organs by narrow FOV. Therefore, it is known as useful device to examine small organs such as thyroid, parathyroid and gall bladder. In general, when we would like to enlarge the size of images and obtain high resolution images by gamma camera in nuclear medicine study, we use pinhole collimator. The purpose of this study is to evaluate the usefulness of Pixelated BSGI gamma camera and to compare to it using pinhole collimator in thyroid scan which is a study of typical small organs. Materials and methods: (1) The evaluation of sensitivity and spatial resolution: We measured sensitivity and spatial resolution of Pixelated BSGI with LEHR collimator and Infinia gamma camera with pinhole collimator. The sensitivity was measured by point source sensitivity test recommended by IAEA. We acquired images considering dead time in BSGI gamma camera for 100 seconds and used $^{99m}TcO4-\;400{\mu}Ci$ line source. (2) The evaluation of thyroid phantom: The thyroid phantom was filled with $^{99m}TcO4-$. After set 300 sec or 100 kcts stop conditions, we acquired images from both pixelated BSGI gamma camera and Infinia gamma camera with LEHR collimator. And we performed all thyroid studies in the same way as current AMC's procedure. Results: (1) the result of sensitivity: As a result, the sensitivity and spatial resolution of pixelated BSGI gamma camera were better than Infinia's. The sensitivities of pixelated BSGI and Infinia gamma camera were $290cps/{\mu}Ci$ and $350cps/{\mu}Ci$ respectively. So, the sensitivity of pixelated BSGI was 1.2 times higher than Infinia's (2) the result of thyroid phantom: Consequently, we confirmed that images of Pixelated BSGI gamma camera were more distinguishable between hot and cold spot compared with Infinia gamma camera. Conclusion: A pixelated BSGI gamma camera is able to shorten the acquisition time. Furthermore, the patients are exposed to radiation less than before by reducing amount of radiopharmaceutical doses. Shortening scan time makes images better by minimizing patient's breath and motion. And also, the distance between organ and detector is minimized because detector of pixelated BSGI gamma camera is small and possible to rotate. When patient cannot move at all, it is useful since device is feasible to move itself. However, although a pixelated BSGI gamma camera has these advantages, the effect of dead time occurs over 2000 cts/s since it was produced only for breast scan. So, there were low concentrations in organ. Therefore, we should consider that it needs to take tests to adjust acquisition time and amount of radiopharmaceutical doses in thyroid scan case with a pixelated BSGI gamma camera.

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Studies on Silk Textile Wash and Wear Finishing (絹織物 Wash and Wear 加工硏究)

  • Choe, Byong-Hee;Lee, Yang-Hoo
    • Journal of Sericultural and Entomological Science
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    • v.23 no.1
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    • pp.47-55
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    • 1981
  • Silk textile finishing has been studied for many years by many workers in order to meet more utilities for various endusers. Such studies, however, could not be successful because any natural fibers are hardly change their natures by artificial treating methods. Textile finishing is of course to improve the mechandise qualities and the poor natures of silk so that it may be available as the best textile fiber in the world. Sometimes, famous trade marked textile plays more power than its quality in the silk market, nevertheless, this should be over line of research activities. Meantime, the silk demand has been also transferred from ladies stocking to other clothes since nylon or other synthetic fibers were developed. That is why, the extension of silk demand should be developed by various research works. Specially, silk is known as difficult textile to handle it during washing or ironing process which happened to depress down the silk usage for house wives. In order to solve such problems, the reporter has been worked for many years and now, he believes that he has developed a proper finishing method to coversuch problems. The developed finishing method may be said to eligible with economical aspect and shorten the dry duration after water washing in half against normal silk textile without harming the specific silk nature. As all of us know, silk fiber starts to denature since it was spinned by silkworm and the fiber is formed as overlapped "S" type curves during its concooning process. After it is made as raw silk or sericin silk, it shows as straight line form, but it changes in to waved form in case refining or degumming process in order return to its original spinned form. Such nature is continued during its textile form and ends with hard ironing nature than other textile fibers. Mean while, the silk fiber keeps to continue its denaturing and this is iniciated by repeat of washing and drying which takes many years to reach its final stage, The reporter has found the iniciating denature of silk by his finishing process, with out heat, decreasing the swollen nature which ended with shortening the drying duration after wash. Each washing was carried out by soaking the previously weighed sample in cold water for one hour, then pressed the sample for ten minutes to eliminate its free water component before weighing with same condition. According to this, the treated silk showed much denaturing after the finishing, but the standard silk progressed the denaturing by and by with the repeat of washing and drying, finally reached the same swollen degree of treated silk, Such treating result explains that the treated silk happened to be stebilized nature by the treating immediately. On the other that the treated silk happened to be stebilized nature by the treating immediately. On the other hand, standard silk may reach to such condition by the time of worn out clothes after repeat of washing and drying for many years while the clothes will be no more useful. The decreased swelling nature has brought about the drying period in half against standard silk after all. Not only the tests of tenacity and elongation but also crease resistance recovery, stiffness and shrinkage tests were carried out after each washing and drying which he has found better result on the treated silk textile against the standard silk. The most important thing was to keep the textile feeling of silk by such finishing work before improve any poor nature of silk. The general silk has a nature to absorb smoke or dirt from its surrounding air and reaches to dirty color shade upon such exposure, but the treated one has improved such nature because of its artificial denaturing, another word, it keeps clean longer than the normal silk. Many previous finishing works could improve some specific nature of silk, but it happened to deprave other important natures. The reporters work is, however, specialized to improve the silk to be useful as Wash and Wear Silk without harming its standard natures. So far, this work happened to be a overall innovative finishing method of silk textile.

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Studies on the ecological variations of rice plant under the different seasonal cultures -I. Variations of the various agronomic characteristics of rice plant under the different seasonal cultures- (재배시기 이동에 의한 수도의 생태변이에 관한 연구 -I. 재배시기 이동에 의한 수도의 실용제형질의 변이-)

  • Hyun-Ok Choi
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.3
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    • pp.1-40
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    • 1965
  • To measure variations in some of the important agronomic characteristics of rice varieties under shifting of seedling dates, this study has been carried out at the Paddy Crop Division of Crop Experiment Station(then Agricultural Experiment Station) in Suwon for the period of three years 1958 to 1960. The varieties used in this study were Kwansan, Suwon #82, Mojo, Paltal and Chokwang, which have the different agronomic characteristics such as earliness and plant type. Seeds of each variety were sown at 14 different dates in 10-day interval starting on March 2. The seedlings were grown on seed bed for 30, 40, 50, 60, 70 and 80 days, respectively. The results of this study are as follows: A. Heading dates. 1. As the seeding date was delayed, the heading dates was almost proportionally delayed. The degree of delay was higher in early varieties and lower in late varieties and the longer the seedling stage, the more delayed the heading date. 2. Number of days to heading was proportionally lessened as seeding was delayed in all the varieties but the magnitude varied depending upon variety. In other words, the required period for heading in case of late planting was much shortened in late variety compared with early one. Within a variety, the number of days to heading was less shortened as the seedling stage was prolonged. Early variety reached earlier than late variety to the marginal date for the maximum shortening of days to heading and the longer the seeding stage, the limitted date came earlier. There was a certain limit in seeding date for shortening of days to heading as seeding was delayed, and days to heading were rather prolonged due to cold weather when seeded later than that date. 3. In linear regression equation, Y=a+bx obtained from the seeding dates and the number of days to heading, the coefficient b(shortening rate of days to heading) was closely correlated with the average number of days to heading. That is, the period from seeding to heading was more shortened in late variety than early one as seeding was delayed. 4. To the extent that the seedling stage is not so long and there is a linear relationship between delay of seeding and shortening of days to heading, it might be possible to predict heading date of a rice variety to be sown any date by using the linear regression obtained from variation of heading dates under the various seeding dates of the same variety. 5. It was found out that there was a close correlation between the numbers of days to heading in ordinary culture and the other ones. When a rice variety was planted during the period from the late part of March to the middle of June and the seedling ages were within 30 to 50 days, it could be possible to estimate heading date of the variety under late or early culture with the related data of ordinary culture. B. Maturing date. 6. Within (he marginal date for maturation of rice variety, maturing date was proportionally delayed as heading was delayed. Of course, the degree of delay depended upon varieties and seedling ages. The average air temperature (Y) during the ripening period of rice variety was getting lower as the heading date. (X) was delayed. Though there was a difference among varieties, in general, a linear regression equation(y=25.53-0.182X) could be obtained as far as heading date were within August 1 to September 13. 7. Depending upon earliness of a rice variety, the average air temperature during the ripening period were greatly different. Early variety underwent under 28$^{\circ}C$ in maximum while late variety matured under as low as 22$^{\circ}C$. 8. There was a highly significant correlation between the average air temperature (X) during the ripening period, and number of day (Y) for the maturation. And the relationship could be expressed as y=82.30-1.55X. When the average air temperature during the period was within the range of 18$^{\circ}C$ to 28$^{\circ}C$, the ripening period was shortened by 1.55 days with increase of 1$^{\circ}C$. Considering varieties, Kwansan was the highest in shortening the maturing period by 2.24 days and Suwon #82 was the lowest showing 0.78 days. It is certain that ripening of rice variety is accelerated at Suwon as the average air temperature increases within the range of 18$^{\circ}C$ to 28$^{\circ}C$. 9. Between number of days to heading (X) related to seeding dates and the accumulated average air temperature (Y) during the ripening period, a positive correlation was obtained. However, there was a little difference in the accumulated average air temperature during the ripening period even seeding dates were shifted to a certain extent. C. Culm- and ear-lengths. 10. In general all the varieties didn't show much variation in their culm-lengths in case of relatively early seeding but they trended to decrease the lengths as seeding was delayed. The magnitude of decreasing varied from young seedlings to old ones. Young seedlings which were seeded during May 21 to June 10 didn't decrease their culm-lengths, while seedlings old as 80 days decreased the length though under ordinary culture. 11. Variation in ear-length of rice varieties show the same trend as the culm-length subjected to the different seeding dates. When rice seedlings aged from 30 to 40 days, the ear-length remained constant but rice plants older than 40 days obviously decreased their ear-lengths. D. Number of panicles per hill. 12. The number of panicles per hill decreased up to a certain dates as seeding was delayed and then again increased the panicles due to the development of numerous tillers at the upper internodes. The seeding date to reach to the least number of panicles of rice variety depended upon the seedling ages. Thirty- to 40-day seedlings which were seeded during May 31 to June 10 developed the lowest number of panicles and 70- to 80-day seedlings sown for the period from April 11 to April 21 reached already to the minimum number of panicles. E. Number of rachillae. 13. To a certain seeding date, the number of rachillae didn't show any variation due to delay of seeding but it decreased remarkably when seeded later than the marginal date. 14. Variation in number of rachillae depended upon seedling ages. For example, 30- to 40-day old seedlings which, were originally seeded after May 31 started to decrease the rachillae. On the other hand, 80-day old seedlings which, were seeded on May 1 showed a tendency to decrease rachillae and the rice plant sown on May 31 could develop narrowly 3 or 4 panicles. F. Defective grain and 1.000-grain weights. 15. Under delay of the seeding dates, weight of the defective grains gradually increased till a certain date and then suddenly increased. These relationships could be expressed with two different linear regressions. 16. If it was assumed that the marginal date for ripening was the cross point of these two lines, the date seemed. closely related with seedling ages. The date was June 10- in 30- to 40-day old seedlings but that of 70- to 80-day old seedlings was May 1. Accordingly, the marginal date for ripening was getting earlier as the seedling stage was prolonged. 17. The 1.000-grain weight in ordinary culture was the heaviest and it decreased in both early and late cultures. G. Straw and rough rice weights. 18. Regardless of earliness of variety, rice plants under early culture which were seeded before March 22 or April 1 did not show much variation in straw weight due to seedling ages but in ordinary culture it gradually decreased and the degree was became greater in late culture. 19. Relationship between seeding dates (X) and grain weight related to varieties and seedling ages, could be expressed as a parabola analogous to a line (Y=77.28-7.44X$_1$-1.00lX$_2$). That is, grain yield didn't vary in early culture but it started to decrease when seeded later than a certain date, as seeding was delayed. The variation was much greater in cases of late planting and prolongation of seedling age. 20. Generally speaking, the relationship between grain yield (Y) and number of days to heading (X) was described with linear regression. However, the early varieties were the highest yielders within the range of 60 to 110, days to heading but the late variety greatly decreased its yield since it grows normally only under late culture. The grain yield, on the whole, didn't increase as number of days to heading exceeded more than 140 days.

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