• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.3
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• pp.99-108
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• 2016

The shuttle breeding of Korean winter wheat has been able to develop high-yielding and day-length-intensive varieties with a wide range of ecologic adoption. However, the phenology of winter wheat has been changed due to recent rises in the winter temperature of Toluca and increasing frequency of high temperatures. We defined two wheat groups (group II and III) with vernalization and evaluated the impact of cold exposure duration and heading ratio due to changes in sowing dates by measuring changes in cold exposure duration and corresponding heading states of each group. The wheat cultivars were sown on three dates in two years. The cold exposure requirement of wheat sown on 6 November 2013 was unfulfilled. The cold exposure requirement of wheat sown on 22 November and 6 December 2013 was fulfilled. However, in 2014, the cold exposure requirement of wheat sown on 5 and 20 November was fulfilled, but that of wheat sown on 5 December was unfulfilled. The differences for the two early November sowings were because winter temperature rises, which caused high temperatures in 2013, whereas early November 2014 saw normal temperatures for the area. The heading ratio of group II did not show a clear difference among the three sowing dates, while the heading ratio of group III was reduced by about half. This implies that the efficiency of shuttle breeding of group III will be high since it showed strong sensitivity to changes in sowing dates. We calculated future sowing dates of each group under near future climate scenarios; the future available sowing dates of group II were projected, but the dates of group III were never estimated in the temperature rise scenario in Toluca. Our findings suggest that change of sowing dates should be considered in the strategy for shuttle breeding of Korean winter wheat.

• The Korean Journal of Food & Health Convergence
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• v.6 no.1
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• pp.17-20
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• 2020

Wheat is the most abundant crop in the world, accounting for one third of the world's population diet. In Ukraine, wheat is in fact, in addition to its nutritional value, a national symbol of the state. Therefore, the main thesis on the development of modern plant growing in Ukraine is the reduction of costs and the introduction of innovative technologies. The quality of grain and seed depends on many factors, namely: agro-climatic conditions, sowing condition of the seed material, quality characteristics of the soil, yielding properties of seeds, pre-sowing seed treatment. etc. For this purpose, the photosynthesis and intensity of photosynthesis need to be limited to the width of the leaf and the height of the leaves by a smaller cut of the stem. It is extremely important to ensure that the head and side pagons of wheat are in good condition. All parameters are often secured by the technology of grain preparation before delivery. Prior to this technology, it is possible to introduce processing of the material in the form for the development of the material. This article presents the effectiveness of the use of infrared irradiation for the pre-sowing treatment of winter wheat seeds in Sekobra Research, Germany.

• Journal of The Korean Society of Grassland and Forage Science
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• v.43 no.2
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• pp.103-108
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• 2023

Due to the recent impact of global warming, heavy rainfall and droughts have been occurring regardless of the season, affecting the growth of Italian ryegrass (IRG), a winter forage crop. Particularly, delayed sowing due to frequent heavy rainfall or autumn droughts leads to poor growth and reduced winter survival rates. Therefore, techniques to improve yield through additional sowing in spring have been implemented. In this study, the growth of IRG sown in Spring and Autumn was compared and analyzed using vegetation indices during the months of April and May. Spectral data was collected using an Unmanned Aerial Vehicle (UAV) equipped with a hyperspectral sensor, and the following vegetation indices were utilized: Normalized Difference Vegetation Index; NDVI, Normalized Difference Red Edge Index; NDRE (I), Chlorophyll Index, Red Green Ratio Index; RGRI, Enhanced Vegetation Index; EVI and Carotenoid Reflectance Index 1; CRI1. Indices related to chlorophyll concentration exhibited similar trends. RGRI of IRG sown in autumn increased during the experimental period, while IRG sown in spring showed a decreasing trend. The results of RGRI in IRG indicated differences in optical characteristics by sowing seasons compared to the other vegetation indices. Our findings showed that the timing of sowing influences the optical growth characteristics of crops by the results of various vegetation indices presented in this study. Further research, including the development of optimal vegetation indices related to IRG growth, is necessary in the future.

• Journal of The Korean Society of Grassland and Forage Science
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• v.6 no.3
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• pp.164-168
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• 1986

This study was conducted at the forage experiment field of SNU, Snweon to investigate effects of sowing time and seeding rate on growth characteristics, winter survival and dry matter yield of forage rye (Secale cereale L.) as fresh-cut forage. Treatments involved 9 combinations of sowing times (September 8, 28 and October 18) and seeding rates(80, 130 and 180kg $ha^{-1}$). Plant height was not influenced by the time of sowing, but forage rye had a tendency to be taller as increasing seeding rate when sown on September 8 and October 28 and harvested in fall and spring, respectively, Winter survival was reduced by fall harvesting in the plot sown on September 8, however, total dry matter yield was increased by the fall harvesting. Average dry matter yields of 5884, 4993 and 3525kg $ha^{-1}$ were obtained when forage rye was sown on September 8, 28 and October 18, respectively. Dry matter yield was decreased as delaying the time of sowing, but a tendency toward higher yield of forage rye by increasing seeding rate was observed. Yield difference by seeding rates was markedly larger when forage rye was sown on October 18 than September 8 and 28. Based on the results of this study, it appears that the dry matter yield of forage rye could be enhanced by sowing early to late September under upland condition in the middle plain are of Korea. The seeding rates of 80 to 130 kg $ha^{-1}$ and 180kg $ha^{-1}$ would be suitable for early to mid fall and late fall sowings, respectively.

• Korean Journal of Agricultural Science
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• v.46 no.3
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• pp.439-449
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• 2019

The purpose of this research was to evaluate the effects of different sowing dates on growth characteristics, seed productivity and feed value of triticale in Gyeongbuk province. The experiment was conducted from September 2015 to July 2017, using triticale "Joseong" cultivar of 150 kg of seed/ha and sown at 10 days intervals from different sowing dates ($30^{th}$ September, $10^{th}$, $20^{th}$ and $30^{th}$ October) in 2015 and 2016, respectively. The emergence date in the autumn season was 8 - 18 days after sowing in 2015 and 2016. The heading, flowering and maturing periods were the fastest on $30^{th}$ September compared to the other sowing dates. The average number of stem and panicle per unit area were 409.3 - 428.5 and 330.9 - 334.0 on $30^{th}$ September and $10^{th}$ October, which were higher than those sown on $20^{th}$ and $30^{th}$ October, 2015 and 2016, respectively (p < 0.05), and the average number of grain and kernel weight was 47.1 - 48.1 and 2.2 - 2.3 g on $30^{th}$ September and $10^{th}$ October, which were higher than the late sowing dates. In case of seed yield as affected by different sowing dates, the highest yield was found on the sowing plot of late September and $10^{th}$ October, which were 5,680 and 5,918 kg/ha, respectively (p < 0.05). However, the average CP content was 10.7%, CF content was 2.8% and TDN content was 85.3. In conclusion, $30^{th}$ September and $10^{th}$ October were the appropriate sowing dates for a forage self-sufficiency system in Gyeongbuk.

• Journal of the Korean Solar Energy Society
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• v.27 no.2
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• pp.19-27
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• 2007

The previous study was conducted to develop an air source multi heat pump system that could be operated with the solar collector and air source heat exchangers as heat source of the system. There is a winter-sowing problems in air source multi heat pump system when the outdoor temperature goes down under freezing point. The winter-sowing problem was solved by adapting R-22 refrigerant as working fluid in the previous study. However, when the system operated at high temperature, another problems are come out such as overheating of the solar collector outlet which lead to the superheat of the compressor inlet of the heat pump system. The condition could deteriorates a compressor in some case. In this study, we installed the anti-superheating devices on the previously developed system. As results of system performance test, COP of the system with anti-superheating technique is 2.4. It is a little improved COP compare to previous study's 2.23. In the results of multi heat source heating system, during operating solar collector, COP is relatively high between $200\;W/m^2$ and $400\;W/m^2$ solar intensity. It is recommended to extend the study on performance optimization with balancing the solar collect and capacity of compressor at higher solar irradiation conditions.

• Journal of The Korean Society of Grassland and Forage Science
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• v.26 no.1
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• pp.31-38
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• 2006

This experiment was carried out to determine the effects of different sowing dates and cultivars on the forage yield and quality of winter rye (Secale cereale L.). The experiment was conducted in a split plot design with three replications. The main plots consisted of two sowing dates such as early (15 September) and late (30 September). The subplots consisted of rye cultivars of five different maturity groups such as 'Kodiak' (Late), 'Koolgrazer' (Early), 'Danko' (Late), 'Homil22' (Medium) and 'Olhomi1' (Early). Dry matter (DM) content at early sowing (19.7%) was higher than those at late sowing (17.8%), while crude protein (CP) and total digestible nutrients (TDN) contents at early sowing (16.6% and 61.6%) were lower than those at late sowing (16.8% and 63.1%). Although DM content of early maturing cultivars (Koolgrazer and Olhomi1) was higher than the other cultivars, CP and TDN contents of those were lower compared to other cultivars. The contents of fiber components (ADF, NDF and cellulose) at early sowing were higher than those at late sowing, while ADL and hemicellulose at early sowing were lower than those at late sowing. ADF and cellulose of early maturing cultivars were higher than those of the other cultivars, while ADL and hemicellulose of Danko were higher than that of the other cultivars. DM, CP, In vitro dry matter digestibility (IVDMD) and TDN yields at early sowing were higher than those at late sowing, and early maturing cultivars were higher than those of the other cultivars. Results of this study indicate that forage production technology in combination with early sowing and use of early maturing rye cultivar could enhance both production and quality of rye.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.3
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• pp.340-346
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• 1985

Field experiments were carried out to investigate the effects of sowing dates, ferrilizer levels and clipping treatment of forage production and quality of barley and rye in paddy field. The field emergence rates in barley varieties was decreased rapidly at sowing after November. But in rye varieties, it was not decreased even in sowing until Nov. 3. Winter survival of barley and rye varieties were not affected by fertilizer levels. And winter survival decreased with delay in sowing dates in barley varieties, but, it was not influenced by sowing dates in rye varieties. The production of forage dry matter at heading stage was increased with fertilizer levels, and was decreased with delay in sowing dates. Content of crude protein and crude fat of dry forage at heading stage were increased with fertilizer levels. But, content of crude ash, crude fiber and TDN were not influenced by fertilizer levels. As increased fertilizer levels, NFE Content was decreased and TDN yield was increased with fertilizer levels. In comparisons of TDN yield between barley and rye varieties, TDN yield of rye were superior to those of barley. Clipping twice produced more forage yield than clipping once in both crops. However, optimum clipping interval was about 40 days between first and second clipping in rye but not determined in barley. The l2cm clipping height was the highest production in average total yield.

• Journal of The Korean Society of Grassland and Forage Science
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• v.24 no.4
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• pp.309-316
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• 2004

This experiment was carried out to assess the growth and development of five rye(Secale cereale L.) cultivars based on the Feekes scale in relation to sowing date at the Experimental Livestock Farm, Seoul National University(SNU), Suwon from 30 September 2001 to 4 May 2002. The experiment was conducted in split plot design with three replications. The main plots consisted of two sowing date such as early(30 September) and late(15 October). The subplots consisted of rye cultivars of five different maturity groups such as 'Kodiak', 'Koolgrazer', 'Danko', 'Homil22' and 'Olhomil'. The plant height of early sowing rye cultivars was higher than that of late one. Among the rye cultivars tested, plant heights of early maturing cultivars were higher than those of the other cultivars. The tiller number at early sowing(48.0) was higher than that of late(24.3), however, late maturing cultivars were higher than those of the other cultivars among the rye cultivars tested. Growth and development in the early sowing were generally three days earlier than those of late sowing cultivars. Growth and development in 'Olhomil' rye cultivars was earlier than 'Danko' rye cultivars when sown in early, but 'Olhomil' and 'Koolgrazer' rye cultivars showed an early maturity than 'Danko' rye when sown in late. Therefore, the developmental stages of winter rye cultivars could be categorised the following maturity; 'Olhomil' and 'Koolgrazer' are early in maturity, 'Homil22' is medium, and 'Kodiak' and 'Danko' are late in maturity.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.4
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• pp.276-280
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• 2005

Low temperature is one of the most severe abiotic stress factors limiting growth, productivity and distribution of winter cereals. Reliable field screening method, which can detect small differences in winter survival, is important for the effective selection and development of plants to identity superior cold tolerant winter cereal genotypes. This study was undertaken to provide improved screening method of winter hardiness in the field by increasing the accuracy in evaluating winter hardiness of barley (Hordeum vulgare L.). We introduced furrow in field screening of winter survival. By sowing the plants at the ridge and base, we could minimize the effect of topographic variation in a field by giving higher and lower level of stress at the same time. This method could be used by breeders to conduct accurate evaluation of winter hardiness by selecting the better treatment, which shows close to normal distribution, among the winter survival rate from the ridge, base and mean survival rate of the two in a screening field.