• Asian-Australasian Journal of Animal Sciences
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• v.13 no.4
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• pp.490-496
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• 2000

In vivo digestibility, nitrogen retention and microbial protein yield from diets of 100% ammonia treated rice straw (ARS) ($D_1$); 65% untreated rice straw (URS)+30% rice bran (RB)+5% SBM ($D_2$) and 85% ARS+15% RB ($D_3$) were determined using three Japanese Corriedale wethers in a $3{\times}3$ Latin Square Design. Results showed that DM consumption and organic matter digestibility were highest in $D_3$; but did not promote high protein digestibility, which RB+SBM had effected in URS based-diet. Dry matter intake and OM digestibility were the same for $D_1$ and $D_3$. Solubility of fiber bonds was increased by ammoniation, resulting in higher NDF digestibility. Nitrogen retention and microbial protein yield of rice bran supplemented groups was higher than ARS, but supplementation did not significantly increase efficiency of microbial protein synthesis from ARS which did occur when RB+SBM was added to untreated straw. The quality of ammoniated rice straw could be improved through RB supplementation because of its positive effects on DM digestibility, nitrogen retention and microbial protein yield. However, the addition of RB+SBM to URS resulted to more efficient N utilization.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.3
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• pp.326-332
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• 2008

This study was conducted to evaluate an early-maturing rice cultivars adaptable to early transplanting cultivation in Yeongnam plain area. High temperature during the ripening stage of paddy rice under the early-transplanting cultivation in Yeongnam plain was to influence in several agronomic traits such as number of spikelet, ripening ratio, grain appearance of milled rice, and yield. 'Gounbyeo' and 'Junghwabyeo' were better than the others in grain appearance of milled rice and ripening ratio, but their yield potential were lower than that of the other varieties. Moreover, 'Gounbyeo' and 'Junghwabyeo' showed high ratio of broken rice. 'Unkwangbyeo' was the highest in yield and eating quality among the tested varieties, but also high percentage of white core and belly in milled rice. Therefore, in order to recommend those cultivars to farmers, it should be needed to establish an optimal cultivation method, such as transplanting density, fertilizer application, and harvesting time, etc. consequently, it should also be required to develop a new varieties with high ripening capability under high temperature condition.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.3
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• pp.214-220
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• 1999

Rice production in Korea has markedly increased during the last two decades due to newly developed high yielding varieties and improved production technology. This experiment was conducted to determine the potential of tropical japonica germplasm in enhancing the yield of temperate japonica. The yield performance of two tropical japonicas (IR 65597-29-3-2 and IR66154-52-1-2) and one temperate japonica (Dongjinbyeo) was compared at different plant densities and nitrogen levels under Korean environmental conditions. Although tropical japonicas showed low tillering habit and large panicles, they had similar leaf area index and dry weight at heading stage to Dongjinbyeo of the high tillering type indicating that there was not much difference between tropical and temperate japonica in terms of biomass production. The highest milled rice yield of 6.15 t/ha was obtained from Dongjinbyeo at a high nitrogen level with less planting density (220 kg N/ha and 30 $\times$ 15 cm). However, those of the two tropical japonicas were 5.36 t/ha at the condition of 165 kg N/ha and 30 x 10 cm planting density and 5.06 t/ha at the condition of 165kgN/ha and 15 x 15 cm planting density, respectively. Ripened grain of tropical japonicas ranged from 65 to 87%, while that Dongjinbyeo ranged from 82 to 97% under Korean conditions.

• Korean Journal of Agricultural Science
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• v.46 no.4
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• pp.791-798
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• 2019

This experiment was conducted to find out the difference between roughage productivity and feed value by using two domestic forage rice cultivars in a mid-west reclaimed rice field in Korea. During the growing period, Na⁺ content in soil showed no significant difference between the two cultivars; however, the K⁺ content in the soil was significantly lower than that in which the Mogwo was grown. The tiller number was 45.5 to 58.8, which was higher than that of Mogyeong, and the leaf number was higher than that of Mogyeong. The dry matter yield per 10 a was 1,338 kg for Moggyang and 1,532 kg for Mogwoo. At the harvest time, the crude protein yield per 10 a produced 108 kg of Mogyang and 170 kg of Mogwoo, and the total digestion nutrient (TDN) yield per 10 a also produced about 617 kg of Mogyang and 880 kg of Mogwoo. To sum up the above results, Mogwo, which has many tiller numbers and leaf numbers, has a high dry matter production, a relatively low neutral detergent fiber (NDF) and acidic detergent fiber (ADF), and a high crude protein yield and TDN yield, and it was better when cultivating the forage rice cultivars in reclaimed land.

• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.4
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• pp.1-10
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• 2019

Unmanned aerial vehicle(UAV) can acquire images with lower cost than conventional manned aircraft and commercial satellites. It has the advantage of acquiring high-resolution aerial images covering in the field area more than 50 ha. The purposes of this study is to develop the rice grain yield distribution using UAV. In order to develop a technology for estimating the rice yield using UAV images, time series UAV aerial images were taken at the paddy fields and the data were compared with the rice yield of the harvesting area for two rice varieties(Singdongjin, Dongjinchal). Correlations between the vegetation indices and rice yield were ranged from 0.8 to 0.95 in booting period. Accordingly, rice yield was estimated using UAV-derived vegetation indices($R^2=0.70$ in Sindongjin, $R^2=0.92$ in Donjinchal). It means that the rice yield estimation using UAV imagery can provide less cost and higher accuracy than other methods using combine with yield monitoring system and satellite imagery. In the future, it will be necessary to study a variety of information convergence and integration systems such as image, weather, and soil for efficient use of these information, along with research on preparing management practice work standards such as pest control and nutrient use based on UAV image information.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.19-19
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• 2017

The indica ${\times}$ japonica rice (Oryza sativa L.) cultivars released in Japan since 1980 are high-yielding. However, occasionally in these cultivars their high yield potentials cannot be realized, particularly depending on climate conditions. The objectives of this study were to identify the reason for yield instability and the critical yield component factor causing lower grain yield in these high-yielding cultivars. Standard-yield japonica, high-yielding japonica-dominant, and indica-dominant cultivars were grown in western Japan. Rough grain yield (RY) in these high-yielding cultivars ranged from 450 to $980g\;m^{-2}$, and was positively correlated with potential grain yield (PRY). By fluctuations of solar radiation, RY changed with spikelet number (SNO), and SNO was correlated with cumulative radiation during the panicle formation period of 30 days before heading. Even if higher SNO was achieved under higher radiant conditions, RY was lower than PRY. The lower grain-filling in plants bearing higher SNO resulted from a lower filling percentage of spikelets (%F, RY/PRY), and %F was strongly correlated with spikelet fertility (%S) across all cultivars. %S was highly influenced by cumulative radiation per PRY during pollen development and establishment around heading. Inhibition of assimilation by leaf removal lowered %S. Conversely, stem thinning and removal of upper panicles around heading increased %S in spikelets of the lower part of the panicle in which sterility was higher. These results suggest that limitation of assimilate-supply due to low irradiance at the spikelet-formation and flowering stages restrains the potential of the high-yielding cultivars, depending on reduction of SNO and %S, respectively.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.43-43
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• 2017

During grain filling period, rice is affected by many environmental factors; including temperature, water, radiation and soil nutrition condition. In future climate, greater shading and heat tolerance will be required in rice. In this study, the effect of shading and high temperature on spikelet sterility was conducted on fourteen Vietnamese cultivars. Field experiments were studied in 2015 and 2016 to evaluate the response of Vietnamese cultivars under high temperature during grain filling stage. The high temperature and shading were applied by closing two sides of growth chamber and covered by a black cloth (50% reduced solar radiation) under the field condition after the first cultivar heading. The sterility increased significantly under high temperature and shading. The highest percentage sterile spiketlets was observed in 'Jasmine 85' (71.7%) under shading and in 'OM4900' (53.4%) under high temperature in 2015 and 2016, respectively. Among the treatments, the percentage of sterile spekelets in Vietnamese cultivars under shading was highest which was 54.9% and 41.8% in 2015 and 2016, respectively. Yield components reduced significantly in both of shading and high temperature. Corresponding with significantly decrease in yield components, the yield in high temperature and shading decreased strongly in both 2015 and 2016.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.7 no.1
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• pp.85-92
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• 1969

The goal for the improvement of rice culture in our country is to increase the rice yield per unit area, and that thoroughly, to equalize the rice yield per unit are highly by adaptation of high technique, while on the side of the efficiency, to increase the productivity of the labour through the cooperative work. And then, the theory for execution of the cooperative rice culture which is the productive system embodying the goal above and the expected effects as well as the future prospect for the development of the cooperative rice culture must be studied and defined. The results studied up to now are summarized as follows: 1. The cooperative rice culture is one of the most effective ways to execute highly efficient farm management and to supply the technical details on the cultivation for equalized high yield per unit area in the rice cultivating districts. 2. For the most effective accomplishment of the cooperative rice culture, the water control, and soil and variety of rice must be investigated in advance an then the basic technical details for the rice culture must be defined. 3. The rice cultivation calender is drawn up with the main technical details of rice culture by the mutual agreement of all farmers belong to the cooperative farm. All technical details for the rice cultivation in the cooperative farm are standardized by the rice cultivation calendar and the main technical operations should be worked together and the other operations executed individually. 4. The technique for rice cultivation, which was difficult to be introduced in the individual farm management, could be introduced easily to the cooperative rice culture, and the rice yield of the cooperative farm was increased 23.3% compared to that of common farm in 1968. 5. At present, the type of the cooperative rice culture is a primary type of the agreement for farm management, rarely including the associated operation type and the contracted operation type for a part of operation, However, for stabilized high yield through the mechanization of the cultivation system, the cooperative farm must be developed for a course promoting the associated operation type including the technique trust type and the contracted operation type according to the condition of location.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.6
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• pp.1293-1297
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• 1999

Effect of rice protein and lipid on rheological properties of gelatinized rice flour solutions(4%) with three rice varieties(Dongjin, Jinmi, Tamjin) known for varying taste of cooked rice was investigated with Haake viscometer. The rheological behaviors of all rice flour solutions were illustrated by Herschel Bulkley equation and exhibited pseudoplastic behavior with yield stress. When rice flour solutions treated with protease and dithiothreitol, there was decreased in flow behavior index value. Flow behavior index was decreased by dealbumin and deglutelin rice flour solutions among deprotein groups. The Jinmi rice flour solutions exhibited slightly lower consistency index than Dongjin and Tamjin. Defatted rice flour solutions exhibited lower consistency index than rice flour solutions, while dealbumin, deglutelin rice flour solutions exhibited high consistency index. Protease treated rice flour solutions exhibited increase in Dongjin and Tamjin. The yield stress was increased in sequence eating quality. Yield stress of defatted rice flour solutions was decreased, while deglutelin and rice starch flour solutions was increased. The time dependent charac teristics of all rice flour solutions appeared forming hysteresis loop and thixotropic behavior showed. The time dependent characteristics was appeared in sequence eating quality. Rice starch and deglutelin flour solutions appeared greatly time dependent characteristics, but defatted rice flour solutions appeared very little.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.1
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• pp.59-63
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• 1999

Yield and growth characteristics were compared for five rice cultivars; a new Tongil-type, so called "super-rice", Dasanbyeo, an old Tongil-type Milyang 23, two japonicas Dongjinbyeo and Ilpumbyeo, and a new plant type (NPT)line IR65600-27-1-2. The objective of this stusy was to clarify the high yielding capacity of Dasanbyeo in terms of growth characteristics. The average grain yield (9 t/ha) of Dasanbyeo was higher than that of Milyang 23 by ca. 9% that of japonicas by 20 to 30%, and that of NPT line by ca. 100%. The higher grain yield of Dasanbyeo was attributable not only to the greater dry matter production but also to the higher harvest index (HI). Dasanbyeo showed the greatest dry matter at harvest owing not only to the rapid leaf expan-sion at early growth stage and the resulting high LAI through the entire growth stage but also to the high NAR despite the high LAI. The rapid leaf expansion of Dasanbyeo at early growth stage seemed to be related in part to the profuse tillering capacity. HI was 0.53 in Dasanbyeo, 0,51 in Milyang 23, 0.41 in japonicas, and 0.35 in NPT line. Dasanbyeo was indebted for its higher HI to the relatively high grain filling ratio in spite of a much greater sink size than the other cultivars. Dasan had a greater source to sink ratio during grain ripening as measured by LAD/spikelet and dry matter production/spikelet which showed positove correlations with the grain ripening ratio. New plant type (NPT) line showed the lowest grain yield owing to the small sink size and the low grain filling ratio which seemed to have resulted from the abundant occurrence of weak-strength spikelets. The weak sink strength, in turn, seemed to have suppressed photosynthesis during the grain ripening stage.