• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.5
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• pp.436-441
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• 1992

This study was carried out to discuss the influences of the different fertilizer levels and plant densities on the flowering and balling in cotton in Mokpo Branch Station, Crop Experiment Station in 1991. The cotton flowered 67% before Aug. 25 which is the limit date of picked-cotton harvest, and the ratio of flowering for stalk-cut cotton was 30%. The 1.5 times fertilizer levels and the 70cm row density had more flower buds, flowers and bolls per m$^2$ than any other treatment plot. The crop growing was bad in dense planting due to the nutrient deficiency. The flowering ratio to flower bud was about 70%, and the balling ratio to flower numbers was about 48%. The bolling ratio was lower in the case of more flower number. The shedding ratio of flower buds was about 30% in average and showed increasing tendency by dense planting. It was observed that the higher ratio of bud shedding tended to accompany with shedding the lower ratio of boll shedding.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.35 no.1
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• pp.1-9
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• 1990

This experiment was carried out to understand the effect of pre-sowing seed treatment by GA$_3$ and IAA on flowering and characteristics of yield component in peanuts. Peanut seed was treated by soaking in 10, 50, 100ppm of GA$_3$ solution, and 50, 100, 200ppm of IAA solution. Treatments of GA$_3$ and IAA resulted 7-5 days earlier emergence and 11-17days shorter of the flowering date compared with the untreated control. By soaking treatments with IAA in 100ppm and GA$_3$ in 100ppm, accumulated flowers were increased at early growing stage of 30 days after flowering compared with untreated control. By soaking treatments with IAA in 100ppm and GA$_3$ in 100ppm, main stem length, branch length and internode of main stem showed to flourish at investigation from early growing stage to 3 days before harvesting.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.285-285
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• 2022

Recent unpredictable climate change is a major cause of rice yield loss. In particular, methane is a key factor in global warming. Therefore rice breeders are trying to breed the reducing-methane gas emission rice using the crossbreeding method. However, the traditional crossbreeding method takes 8 to 10 years to breed a cultivar, and the anther culture method developed to shorten the breeding cycle also takes 6 to 7 years. On the other hand, CRISPR/Cas9 accurately edits the target trait and can rapidly breed rice cultivars by editing the target trait as a homozygous in 2-3 years. In addition, exogenous genetic elements such as Cas9 can be isolated from the G₁ generation. Therefore, the flowering time was regulated by applying CRISPR/Cas9 technology, and OsCKq1 genome-editing (OsCKq1-G) rice with early flowered and high yield was bred in the field. Genome-editing of OsCKq1 applied CRISPR/Cas9 technology up-regulates the expression of the flowering promotion gene Ehd1 under long-day conditions induces early flowering and increases the yield by increasing the 1,000-grain weight. And as the generations advanced, each agricultural trait indicated a low coefficient of variation. As a result, indicated that OsCKq1 plays an important role in regulating the flowering time and is related to the trait determining yield. Therefore, OsCKq1-G can suggest a breeding strategy for the Net-Zero national policy for reducing-methane gas emission rice by shortening the breeding cycle with the early flowered, and high-yield rice. CRISPR/Cas9 technology is a rapid and accurate breeding technology for breeding rice cultivars with important characteristics.

• Korean Journal of Environmental Agriculture
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• v.27 no.4
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• pp.356-361
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• 2008

Chrysanthemum indicum L. (Gamgug) has been examined to study their flowering habits, yields and bioactive compounds under different planting densities and mowing dates. The planting density experiment revealed a significantly increasing stem diameter, number of flowers and branches with decreasing plant density in the $100\;cm{\times}30\;cm$ and $130\;cm{\times}30\;cm$ treatments as compared to $70\;cm{\times}30\;cm$ treatments, but not plant height, leaf and flower width. On the other hand, the mowing date experiment showed that growth characteristics of plants were similar to the control plants (not mowing) and June 20 treatment, but July 20 treatments had significantly smaller than the control. The weights (g $plant^{-1}$) of dry flowers were affected by the planting density and mowing date. The flower yield of $586\;kg\;ha^{-1}$ obtained at $100\;cm{\times}30\;cm$ density was 11% and 22% higher than that of $120\;cm{\times}30\;cm$ and $70\;cm{\times}30\;cm$ treatments, respectively. The yield of dry flowers in the control and June 20 mowing date ranged $495-508\;kg\;ha^{-1}$, which is 40-42% higher than the yield in the July 20 treatments. The amount of essential oil (g $plant^{-1}$) in medically valuable flowerheads of C. indicum L. was statistically different between mowing dates but not among planting densities. The study showed that planting density and the mowing date could increase yields of flowerheads. An optimum planting density of $100\;cm{\times}30\;cm$ and mowing date of on or before June 20 is recommended for C. indicum L.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.3
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• pp.241-247
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• 2020

Sesame is typically a temperature- and day length-sensitive plant, as its flowering is promoted under high temperature and shorter day length conditions. The experiment carried out in the present study revealed that day length influenced sesame flowering to a much greater extent than temperature. The degree of day length influence differed depending on the sesame variety. Days from sowing to flowering was negatively correlated with yield-related characteristics such as stem length, capsule number per plant, 1,000 seed weight, and seed weight per 10a. In cases where the period from sowing to flowering was longer and flowering date was later, the reproductive growth period was shorter during maturity. Analysis of the effects of temperature and day length on seed yield production revealed that temperature was a much more influential factor than day length. However, day length was more influential than temperature under low temperatures, such as 22℃. All varieties apart from Ansan were shown to be primarily influenced by temperature. Sesame varieties were grouped in view of optimal seed sowing time through principal components analysis. The Poongsung and Sungboon varieties favored early sowing under low temperatures and short day lengths. The DT45, Poongsung, 90 days, Ansan, and Sungboon varieties favored late sowing under high temperatures and long day lengths. The Yangbaek and Arum varieties could be sown both early and late.

• Korean Journal of Plant Resources
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• v.15 no.2
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• pp.144-149
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• 2002

This study was carried out to find out the effects of date and number of defoliation by different seeding date on growth and yield of perilla. Saeyuepsildlkkae was seeded from April 30 to June 30 at 20 days interval and defoliated from June 30 to Aug. 15 with different defoliation number. 1. Days to emergence, flowering, and maturing were not significantly influenced by defoliation, but those were shortened as seeding date was delayed. The interaction between defoliation and seeding date showed no significant difference. 2. Stem length, number of nodes on main stem, and weight of dry stem were not significantly affected by defoliation, but those were decreased as seeding date was delayed. 3. Yield of fresh loaves was not significantly influenced by seeding date up to May 20, but markedly decreased by the later seeding date. 4. Cluster length and number of cluster per plant were not affected by seeding date, but number of capsules per cluster was decreased from 32 to 25 and 1,000 grain weight was increased from 3.42 to 4.62g as seeding date was delayed. 5. Grain yield was not significantly affected by defoliation and seeding date up to June 10, but markedly decreased by seeding date June 30.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.100-100
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• 2022

This study was conducted in 2021 using Kwangpyeongok and Gangdaok, that showed good yield performance both under upland and lowland conditions in the previous year. The experiments were carried out by sowing on April 22, May 14, May 30, June 19, and July 10, with aim to determine optimum sowing date in central region of Korea. The growing degree days (GDD) required to read the flowering stage were 1375.5-1725.3℃ for upland and 1582.7-1982.4℃ for lowland condition. The lowest GDD was observed in July 10 sowing regardless of ridge formation both under lowland and upland conditions for Kwangpyeongok. However, Gangdaok showed the lowest GDD under no-ridge in lowland and high-ridge in upland, both of which were sown on June 19. The difference in GDD between no-ridge and high-ridge treatment was little depending on the sowing date. In both lowland and upland, there was no significant difference between no-ridge and high-ridge treatments in stover dry matter, ear dry matter, and TDN between no-ridge and high-ridge treatments. Under upland condition, no significant difference in biomass and TDN was observed among sowing date treatments and between varieties. Under lowland condition, biomass production was severely reduced in May 30 sowing treatment, whereas no varietal difference was observed. Reduced biomass in May 30 sowing treatment may be due to excess waterlogging and lodging by rainfall.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.1
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• pp.67-71
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• 1984

These experiments were conducted at field and green house in order to screen the resistant sesame varieties to Phytopthora nicotianae var. parasitica. and to ascertain the infection conditions of Corynespora cassiicola at different temperatures, soil moistures and leaf stages. Most of varieties studied in this experiment were very susceptible to the Phytopthora blight. Orotall, Suweon 7, Suweon 27 and Jochiweon were resistant to the disease. PI280795 and IS103 showed a tendency to be morderately resistant. The infected areas by Corynespora leaf blight were 15% in Kwangeui and 25% in Kimpo variety at high temperature condition of 3$0^{\circ}C$, respectively. The infection areas were 50% in Kwangeui and 70% in Kimpo variety at low temperature condition of 17$^{\circ}C$. These results indicate that the development of the leaf blight was highly increased at low temperature. The infection areas by the Corynespora were 55% in Kwangeui and 80% in Kimpo at wet soil moisture condition, and 10% in Kwageui and 15% in Kimpo at dry condition, respectively. The infection of the leaf blight was highly increased at 6 leaf stage and flowering date compared to at 10 and 20 leaf stages. The infection ratios were 20% at 6 leaf stage and 52.5% at flowering date, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.28 no.2
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• pp.211-215
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• 1983

Thirty eight varieties with high uniformity and clearance in grain quality among 70 colored soybeans collected from nation-wide provinces were investigated for their seed morphological and agronomic traits. As for seed morphological traits, grain volumetric size, grain weight, grain length, grain thickness, . hilum length and width were studied on the tendency of statistical dispersion and variations. As a result, four groups could be classified on the basis of 100 grains weight, so as small, medium, large, and super large groups, Also, as for agronomic traits, among others, the tendency of setting in flowering date, maturing date, yield components, and stem weight, stem length were studied on the basis of statistical inter-relationships between above mentioned characteristics. From the above, bigger variations were detected in weighing characters of soybean plants than in duration characters. And the flowering and maturing days showed significant relationships to the stem length, stem weight, also stem length and stem weight to the grain yield.

• Korean Journal of Plant Resources
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• v.29 no.4
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• pp.504-510
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• 2016

This study was investigated to find the effects of sowing time on growth and yields of cowpea grown in a southern region of South Korea. Experiments were carried out in Naju, Jeonnam Province (Latitude 35° 04' N, Longitude 126° 54' E) during 2013 and 2014. The intermediate-erect type strains used in this study were Jeonnam1 and Jeonnam2 (Okdang). Sowing time was performed between middle-April and middle-August at intervals of one month. The days from sowing to emergence was significantly higher in the middle-April sowing (12 days) time but there was no significant differences other sowing dates (5 to 3 days). The days from sowing to first flowering were shorter for sowing dates between middle-April and middle-July because sowing time was delayed and then were lengthened again at middle-August sowing; the days were longest at middle-April sowing (around 62 days) and were shortest at middle-July sowing (35 days). The days from first flowering to harvesting were short for the sowing dates between middle-April and middle-July (17 to 15 days) but were relatively long for middle-August sowing date (24 days). Stem length was relatively long for the middle-May and middle-June sowing dates. Peduncle length was relatively long for the middle-April sowing date. Main-stem node number was highest for the middle-July sowing. Branch number per plant was highest in the middle-April sowing. Seed yields were highest for the middle-April sown Jeonnam1 and the Jeonnam2 (Okdang) strains showing, 199 and 211 kg/10a, respectively, and then followed by sowing in middle-July, 191 and 195 kg/10a, respectively.