• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.2
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• pp.203-211
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• 1995

This study was conducted to know how low temperature response of rice varieties is available for breeding lines adapted to cold weather. Some agronomic characters related to cold tolerance were evaluated for 188 varieties including three varietal types of Japonica, Tongil, and Indica. Cold tolerance of Japonica and Indica type varieties varied in leaf discoloration, heading delay, reduction of culm length, panicle number, spikelet number, panicle exsertion, spikelet fertility, and phenotypic acceptability at maturity, while Tongil type varieties were susceptible in most agronomic characters. In leaf discoloration, most Japonica type varieties were highly tolerant, while Indica type varieties showed various responses from tolerant to susceptibility. Not significant difference among three varietal types was observed on reduction of panicle number and spikelet number due to low temperature.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.1
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• pp.49-55
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• 1997

For the labor-saving cultivation of barley in rice-barley double cropping system in paddy field, a series of expriments on the effect of rice straw application were carried out at the National Yeongnam Agricultural Experiment Station from 1992 to 1993. The affection of phenol compounds released from fresh rice straw could be lessened when seeded under rice straw in the soil and that made emergence rate increase by 11％, compared with that on application on the rice straw. Although utilization of rice straw as an organic material caused the poor growth of barley in early stage, it could be enhanced the culm breaking strength. On this reason, affected by rice straw, grain yield was increased from 8％ in common barley and up to 20％ in malting barley. The more nitrogen, CaO$_2$2 and SiO$_2$ applied, the more decomposition of rice straw accelerated from 2％ to 6.9％. On the application of rice straw as an organic material in malting barely cultivation, the content of crude protein was decreased while 1,000-grain-weight and grain assortment was increased.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.2
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• pp.71-76
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• 1998

To define the relations between endogenous GA levels and growth and flowering in short-day plant sorghum, growth retardant BX-112 was applied to two sorghum genotypes, wild-type and phytochrome B mutant (phyB-1), which grows faster and flowers earlier than the wild-type. BX-112 and $GA_3$ were applied as a soil drench, and plant height, culm length, and date to floral initiation were investigated. Endogenous GAs contents were measured with GC-MS-SIM. BX-112 treatments inhibited shoot growth in both genotypes and drastically reduced $GA_1$ and $GA_8$ levels. With increasing BX-112 concentrations, $GA_1$ concentrations declined linearly, but caused the accumulation of intermediates from $GA_12$ to $GA_20$. This result implies that $GA_1$ is the major active endogenous GA in shoot elongation in a short day plant sorghum. The inhibition of plant growth in both of wild type and phyB-1 by BX-112 was very similar, while BX-112 effects on floral initiation in two types of plants differed significantly. Floral initiation of phyB-1 was not affected by BX-1l2, but that of wild-type was delayed as BX-1l2 concentration increased. Because BX-112 treatment causes accumulation of biosynthetic intermediates between synthetic pathway from $GA_12$ to $GA_20$ and because phyB-1 is altered in GA metabolism in this same region of the early C13-hydroxylation pathway, BX-112 may fail to block flowering of phyB-1.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.24 no.3
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• pp.7-12
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• 1979

Seven hundred and forty eight rice cultivars were screened for drought tolerance at seedling stage in a special green house. A number of cultivars such as Wonkiljo, Hanyangdo, YR 52-$_{x}\textrm{BF}_7-67, Satominori, Mamoriaka, Akanomochi 114, Thkebenimochi, IR 937-55-3, IR2735-F_3B-6-2, IR 2871-53-2, $_{x}\textrm{BFI76}^9/Dwan, Khoo lliok Mali-4-2-105, Os6, Palawan, IRAT10, TOS 2583 and H-l05 seemed to be tolerant to drought at seedling stage. There was negative correlation between drought resistance score and growth of plant height and water content of culm and leaf after drought treatment, and highly positive correlation between resistance to blast and resistance to drought at seedling stage. There was no relationship between drought resistance and germination speed, plant height before drought treatment.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.1
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• pp.9-15
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• 1992

To establish the method of direct seeding cultivation in rice (Oryza sativa L.), direct surface seeding with treatments of N application rate, application of growth regulator(PP333), and seeding rate were conducted from May to Oct., 1989 at the experimental field of Sunchon National University. There were no significant differences among treatment means of N application rates, and seeding rates, which seemed to be due to severe occurrence of field lodging. Application of PP333 reduced culm length by 3-4m, but it did not affect the occurrence of lodging. The optimal seeding rate to maximize the number of spikelets per unit area was estimated to be 6kg seed /10a. To obtain stable yield in cultivation of direct surface seeded rice in submerged paddy field, it was necessary to reduce occurrence of field lodging through breeding of lodging resistance genotypes rather than cultural practices.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.3
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• pp.179-183
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• 2004

This study was conducted to investigate the effects of using barley seeder attached to rice harvest combine that could be used in rice harvesting and barley seeding simultaneously on the growth characteristics of barley and labor-saving efficiency. In developed seeding system, burley seeding was earlier about 5 days than in the conventional system, because of conducting rice Harvesting and barley seeding simultaneously. The germination of barley seed after seeding was protected from drought damage by the rice straw covering. Among the growth characteristics of barley using developed seeding system, the number of spikes per m$^2$ was lower than that of conventional system, but others showed longer culm length, hove kernel numbers per spike and heavier 1,000 kernel weight than those of conventional system. Developed seeding system resulted in about 57% labor-saving efficiency compared with conventional system. The cost of whole works from seeding to harvest of barley was saved about 8% compared with conventional system. A total of income increased about 16% than that of conventional system.

• Korean journal of applied entomology
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• v.22 no.3 s.56
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• pp.193-197
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• 1983

In 1981 Rice Black-Streaked Dwarf Virus (RBSDV) was severely occurred in Yeongnam area of Korea. The influence of RBSDV to rice plant was studied with two susceptible cultivars, Nagdongbyeo and Cheongcheongbyeo. The stunting rate was determined by the percentage of plant height of infected plants vs. healthy plants. When the rice plants were severely stunted by RBSDV, the yield components and yield were greatly reduced. The stunting of rice plants infected with RBSDV was caused mostly by the shortening of internodes in upper parts of the culm. The relationship between stunting rate of rice plants and yield was shown to have a negative exponential correlation. The regression equations of the relationship are experssed as follows: In Cheongcheongbyeo $Y=46.6lxe^{-0.0624_\chi}$, and in Nagdongbyeo $Y=54.82xe^{-0.067_\chi}$.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.6
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• pp.471-474
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• 2002

This experiment was conducted to investigate the response of rice growth and grain yield to night illumination. Three cultivars Heugjubyeo (early maturing), Hwaseongbyeo (medium maturing), and Ilpumbyeo(mid-late maturing) were tested under different light intensities ranging 1.0 to 20.0 lux (0.3 to 5.6 $1\mu\textrm{W}$ $cm^{-2}$). Awn length of all cultivars became longer as night illumination intensity increased; 4.09 cm under 10-20 lux compared to 1.93cm under 2 lux in Hwaseongbyeo. However culm and spike length ere not affected by night illumination. Night illumination delayed flowering by 3 days in Heugjinjubyeo, 5 days in Hwaseongbyeo, and 9 days in Ilpumbyeo at 10-20 lux compared to that at 2 lux. Grain yield was reduced by 10.0% in Heugjinjubyeo, 17.7% in Hwaseongbyeo, and 20.7% in Ilpumbyeo at 10-20 lux compared to 2 lux condition.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.3
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• pp.185-189
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• 2000

The object of this study was to determine the optimum seeding dates of "Donganbyeo", "Daesanbyeo", Hoanbyeo", "Nonghobyeo", and "Gwnganbyeo" for direct seeding on dry paddy in Youngnam region. Dry seeds of these varieties were sown 5 times with 10-day intervals from April 20 to May 30. It took 13 to 14 days from sowing to emergence. It was shortened in the delayed seeding date, but the emerged seedlings per unit area was decreased as the seeding date was advanced before May. Heading date was delayed as seeding was delayed. Culm length, panicle length and number of spikelets per panicle was not affected by seeding date, but number of panicle per $m^2$ and ripened grain ratio were high from April 30 to May 10 seeding date. Consequently, the optimum seeding date for high yield of "Donganbyeo", "Daesanbyeo", "Hoanbyeo", "Nonghobyeo", and "Gwanganbyeo" was estimated May 3, May 2, May 10, May 8, and May 1, respectively and "Gwanganbyeo" was estimated May 3, May 2, May 10, May 8, and May 1, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.4
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• pp.412-418
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• 1985

Two fertilizer levels were treated to the nine barley varieties developed at different years to investigate the morphological and physiological traits related to grain yields. Recently developed varieties were higher in amounts of chlorophyll and nitrogen content of leaf, root activity, root weight and specipic leaf weight as compared with older varieties. Dry matter production was closely related to NAR rather than LAI in new varieties, but indicating the reverse results in older varieties. They showed higher NAR and light transmission rate in new varieties but higher LAI in older varieties. Leaves in new varieties were distributed uniformly according to its position on clum. However, leaves in older varieties arranged irregularly showing more distribution at the upper and middle positions on culm. The factors which showed high correlations with grain yield were chlorophyll content, root activity, NAR, and nitrogen content of leaf of which stepwise multiple regression with grain yield indicated that 90% of total variance was occupied by chlorophyll content, root activity and dry matter.