• Korean Journal of Environmental Biology
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• v.37 no.4
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• pp.682-689
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• 2019

The Korean flowering cherry is a popular tree. However, the trees have started to defoliate early, including those in Gurye. Thus, it is necessary to identify the causes of the early defoliation and how to manage them. Therefore, the purpose of this study was threefold: 1) to investigate the early defoliation of flowering cherry trees, 2) to identify the differences in growth and flowering of the trees in response to treatment, and 3) to suggest an optimal treatment for the trees. The experiment was conducted in Gurye at a site 3km long with 102 flowering cherry trees along a street. There were three treatments: control, an environmentally friendly insecticide and a disinfectant(treatment 1), and an environmentally friendly insecticide, a disinfectant, and irrigation (treatment 2). The trees in Gurye were compared to trees on Jeju Island. The defoliation rates of the flowering cherry in Gurye were significantly higher than those on Jeju Island at each measurement time. Within Gurye, the defoliation rate was significantly higher in the trees of the control than in the two treatments and only the trees in the control from Gurye had shot-hole disease. Post-treatment, twigs collected from the control during April showed significantly poorer growth, lower numbers of flowering buds per twig, and lower numbers of foliar buds. The trees given treatment 1 showed significantly greater growth, number of total buds, flowering buds per twig, and density of buds than the trees given treatment 2. After analyzing the correlations, it was established that early defoliation led to poorer growth, affecting the flowering of the trees.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.2
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• pp.50-56
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• 1964

1. Five varieties of kenaf, Hibiscus cannabinus L., were used for study the influence of various patterns on flowering and fertilization. e statistical analysis on the percentage of flowering in given time gave highly significant different patterns among five varieties examined. Korean local kenaf was flowered very early, whereas Everglades 71 flowered very late. Both Guatemala 38F and Guatemala 2A introducedf rom Guatemala were flowered intermediately to compare with Korean local and American varieties. 3. The data indicate that low temperature was given delayed flowering time which means the flowering time was closely related with temperature having the flowering time was accelerated more or less early by high temperature. 4. It was shown that the fertilization after pollination was needed for five to six hours. 6. It was examined that the adequate crossing time between different varieties on the kenaf was the time of heavy flowering.

• The Korean Journal of Ecology
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• v.1 no.1
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• pp.17-23
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• 1977

Flowering dates of 389 plant species in the Hongneung Arboretum, Seoul, had been recorded from 1968 through 1975. The thermal analysis on the air temperature as the key factor determining the first flowering date, with climatological data obtained in the Arboretum, were undertaken by Nuttonson's Index (1948) and Lindsey & Newman's Index (1956). The results and conclusion in this study are as follow; Peak in the bell shape distribution curve of the species and first flowering dates, largely, was early May. Flower spans of most species were 10 to 20 days, neverthless, some species flower only a few days while others may stay flowering a hundred days even more. Increase-curves of summation temperature from early spring through late-summer showed almost the same mode in both Nuttonson;s Index (Tn) and Lindsey & Newman's Index (T1). These Indices manifested the exponential curve, increasing slowly at the beginning of spring chiefly but rapidly from the middle part of April. The equation of the linear relationahip between Tn and Tl as far as in thisstudy is as follow. Tl=230Tn It appears that the distribution of summation temperature, below Tn=400°C·day, affects the first flowering, even though it could be modified somehow by the distribution of precipitation, day length and others. Nuttonson's Index (Tn.f) and Lindsey & Newman's Index (Tl.f) upon the thermal amount first flowering dates have been respectively simulated as follow. Tn.f=θa + C Tl.f=230θa + 230C where θ is air temperature 10°C, a and C are a constant.

• Molecules and Cells
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• v.42 no.5
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• pp.406-417
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• 2019

RICE FLOWERING LOCUS T 1 (RFT1) is a major florigen that functions to induce reproductive development in the shoot apical meristem (SAM). To further our study of RFT1, we overexpressed the gene and examined the expression patterns of major regulatory genes during floral transition and inflorescence development. Overexpression induced extremely early flowering in the transgenics, and a majority of those calli directly formed spikelets with a few spikelets, thus bypassing normal vegetative development. FRUITFULL (FUL)-clade genes OsMADS14, OsMADS15, and OsMADS18 were highly induced in the RFT1-expressing meristems. OsMADS34 was also induced in the meristems. This indicated that RFT1 promotes the expression of major regulatory genes that are important for inflorescence development. RFT1 overexpression also induced SEPALLATA (SEP)-clade genes OsMADS1, OsMADS5, and OsMADS7 in the greening calli before floral transition occurred. This suggested their possible roles at the early reproductive stages. We found it interesting that expression of OsFD1 as well as OsFD2 and OsFD3 was strongly increased in the RFT1-expressing calli and spikelets. At a low frequency, those calli produced plants with a few leaves that generated a panicle with a small number of spikelets. In the transgenic leaves, the FUL-clade genes and OsMADS34 were induced, but SEP-clade gene expression was not increased. This indicated that OsMADS14, OsMADS15, OsMADS18, and OsMADS34 act immediately downstream of RFT1.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.7 no.1
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• pp.129-132
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• 1969

The polygenic variation in flowering time of soybean irradiated with Co$^{60}$ gamma ray evaluated in the R$_2$ generation. The genetic variance in the irradiation treatment was about four times that of the control. The basic possibility of selection for the early and the late in flowering time of soybean after irradiated with Co$^{60}$ was suggested in this paper.

• 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 Plant Resources
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• v.28 no.1
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• pp.111-118
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• 2015

The objective of this study was to determine the response of rapeseed (Brassica napus) to different planting date in the spring and varieties on growth and flowering characteristics. Eight rapeseed varieties were sowed at 10 day interval from 1st to 31th of March at Muan and Jeju in Korea. Significant planting dates and rapeseed varieties effects for growth, start of flowering and duration. As the planting date was being delayed, plant length and flower number were decreased, but branch number was increased. And, start of flowering date was retarded and flowering duration decreased with later planting date. Days from planting to flowering was shortened as seeding date was delayed and shortening degree was similar between experimental locations, Muan and Jeju. The days to flowering for rapeseed about 73~94 days for 1st March and then decreased to 57~71 days for the 31th March of planting date. 'Tammiyuchae' and 'Mokpo 111' seeded on each planting date come into blossom more earlier about 10 days as compared to 'Tamlayuchae' and 'Naehanyuchae'. The duration of flowering for the B. napus varieties was shortened as planting date was delayed. The results revealed that flowering characteristics of rapeseed can be greatly enhanced by planting as early as possible, and early flowering varieties i.e. 'Tammiyuchae' and 'Spring' were the most suitable varieties among the tested varieties for planting in the spring.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.2
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• pp.113-117
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• 2006

To identity the effect of sowing dates on flowering and maturity of sesame, some agronomic traits including days to flowering and days to maturity were investigated under five different sowing dates. Plant height, days to flowering, days to maturity, days from flowering to maturity and number of capsules per plant were showed significantly different by years, sowing dates and varieties. Interaction between sowing dates and varieties affected to days to flowering, days to maturity, days from flowering to maturity and number of capsules per plant. Plant height, days to flowering and days to maturity decreased significantly as sowing dates were delayed, but number of capsules and seed weight per plant showed highest at the sowing date of May 10. At the regression analysis of shortness degree of growth period by the response of days to flowering and days to maturity under different sowing dates, sesame varieties with earlier flowering habit were much less affected by day length rather than ones with later flowering habit. $R^2$ and gradient value on the days to maturity regression graph were smaller indicating that maturity was much less sensitivity than flowering to the change of day length and temperature in the move of sowing dates. Therefore, it would be concluded that early maturity sesame varieties have higher potential adaptability to various sesame cropping systems in view of their less sensitivity to day length changes under different sowing dates.

• Journal of Plant Biology
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• v.19 no.1
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• pp.14-18
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• 1976

Inhibition of flowering in Lemna perpusilla 6746 by 30 mM sucrose was reversed by the addition of acetylcholine (>$10^{-4}M) supplemented with 10^{-4}M$ ascorbic acid to 1/10-strength Hunter's growth medium. The reversible effect of acetylcholine was found to be greater at early stages of flowering than in the later period. Promotive effects of both acetylcholine ($10^{-3}M) and eserine(10^{-5}M$) on flowering in the short-day plant under various photoperiodic conditions were studied. It was indicated that the application decreased length of the critical dark period for the floral induction, and it was also shown that the endogenous status of acetylcholine was involved in the floral response which had a correlation with phytochrome. Interruption of inductive dark periods by red irradiation (1min) immediately followed by far-red light (1 min) completely inhibited flowering, while the addition of acetylcholine and eserine to the medium under the same condition slightly promoted flowering, indicating possible involvement of phytochrome system in acetylcholine activity for photoperiodic sensitivity of floral response in Lemna perpusilla 6746.

• Journal of Plant Biotechnology
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• v.1 no.2
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• pp.109-115
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• 1999

A linkage map of Capsicum annuum L. was constructed by random amplified polymorphic DNA (RAPD) markers followed in a backcross population of an intraspecific cross between cultivars HDA210 and Yatsufusa. A total of 420 random primers were tested and 311 polymorphic bands were generated by 158 random primers. Among them, 86 Yatsufusa specific bands generated by 52 primers were examined for mapping. Most bands except three segregated in Mendelian fashion fitting the expected 1:1 ratio. The total length of the map was 533 cM distributed in 15 linkage groups. The map distance between adjacent markers ranged 0 to 32.8 cM, with an average distance of 9.1 cM (63 markers). Some markers were clustered and this may be due to the amplification of a repetitive sequence by the RAPDs. Primer pairs for a sequence characterized amplified region (SCAR) were developed and the segregation scores by the SCAR primers were in accordance with the RAPD data. Two QTL markers for number of axillary shoots and for early flowering were developed. One QTL for early flowering located in the linkage group 3 and explained 61 "io of the phenotypic variation. The other QTL for the number of axillary shoots located in the linkage group 4 explained 55 % of the phenotypic variation.tion.