• Korean Journal of Soil Science and Fertilizer
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• v.45 no.1
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• pp.16-19
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• 2012

Increasing rice grain yield is critical for feeding rapid increasing of Asian population. However, global warming effect may be negative for sustainable rice production. Therefore it is essential to develop technologies not only for increasing grain yield but also for reducing global warming effect. Biochar, which is carbonized biomass, has a great potential of carbon sequestration and soil quality improvement, which can contribute grain yield increasing. In this study, rice yield responses to biochar application on the rice cropping system were evaluated with field experiments under different water management practices at the research farm of the University of Missouri-Columbia Delta Research Center, Portageville, MO. Biochar (i.e., $4Mg\;ha^{-1}$) was produced using field scale pyrolyzer and incorporated into the field 4 months prior to planting. Rice was grown under three different water management practices. Result showed that no significant yield difference was found in the biochar application plots compared to rice hull and control plots from the 2 years field study at the very fertile soil. However, rainfed management results in severe reduction of yield. Research concludes that the biochar application does not significantly influence on rice yield increasing especially for very fertile soils.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.73-76
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• 2006

This study was carried out to investigate the change yield and grain quality in rice caused by damages of brown planthopper (Bph) on major agronomic traits at the ripening stage. A major agronomic traits such as culm length, panicle length, number of panicle and number of grain per panicles was no-significant difference compared hopperburn area (HBA) and moderately damaged area (MDA) by brown planthopper with non-damaged area (NDA). but, the ripeing ratio and yield in HBA and MDA was significantly decreased. The perfect rice of brown rice in HBA and MDA was also lowered than the NDA and the immatured grain among imperfect rice in damaged area by BPH was significantly increased than in the NDA. Among the traits related with palatability of cooked rice, the amylose content was not affected by damage of brown planthopper, whereas, the protein content was significantly increased in the HBA and MDA. additionally, Peak viscosity in HBA and MDA is lower than the NDA, and setback was increased. In most cases, there was negative on yield and grain quality by the damage of brown planthopper at the ripening stage. Thus, the rice product harvested in damaged area should be separated with that in non damaged area for grain market quality of milled rice.

• Journal of Environmental Science International
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• v.30 no.8
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• pp.659-671
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• 2021

The physicochemical properties of soil and the yield and quality of rice (Oryza sativa L. cv. Sailmi) were assessed using Italian ryegrass (Lolium multiflorum Lam. cv. Kowinearly)-rice double cropping systems in the paddy fields at Goseong and Miryang in southern Korea. The average temperatures during the ripening period were approximately 1 ℃ higher than the optimal temperature for rice ripening and the sunshine duration was reduced by frequent rainfall. Consequently, it was slightly below the optimal conditions required for rice ripening. In the soil at Goseong, winter Italian ryegrass cropping increased the pH, electrical conductivity, and the contents of organic matter, total nitrogen (T-N), available P₂O₅, K, Ca, and Mg than winter fallowing. Particularly, the contents of T-N and available P₂O₅increased significantly. In the soil at Miryang, Italian ryegrass slightly increased the electrical conductivity and the T-N, Mg, and Na contents. Therefore, winter Italian ryegrass cropping improved the physicochemical properties of paddy soils; however, Italian ryegrass-rice double cropping slightly reduced the culm length at both Goseong and Miryang, without markedly changing the panicle length or number compared to fallow-rice cropping. Furthermore, at Goseong, Italian ryegrass-rice double cropping slightly decreased the spikelet number and milled rice yield, and increased the ripened grain rate; however, at Miryang, contrasting results were observed. In addition, fallow-rice cropping revealed no differences in the head rice or opaque rice rates. The protein content was slightly increased in Italian ryegrass-rice double cropping, without significant changes in the amylose content or Toyo value, compared to that in fallow-rice cropping. The peak and breakdown viscosities were slightly decreased. These results indicate that winter Italian ryegrass cropping might alter rice taste but may not exhibit remarkable negative effects on rice cultivation. Therefore, Italian ryegrass-rice double cropping system is recommended for paddy fields in southern Korea. Nevertheless, to increase the rice yield and quality, fertilization standards for rice cropping that consider the changes in the T-N and organic matter contents in paddy fields caused by winter Italian ryegrass cropping need to be established.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.spc
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• pp.19-23
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• 2008

This study was conducted to compare the yield and grain quality as affected by rice seedling age in late transplanted rice. The rice yield was remarkably reduced in 10 day-old seedlings but those of older seedlings over than 30-day were not different. In the rice quality, as the rice seedling age younger the rate of greened and damaged rice increased, suggesting decreasing of the head rice rate. Among the physicochemical characteristics, protein content of rice grain was increased in 10 day-old seedling but amylose content was not different, consequently, the palatability was improved in older seedlings over than 30-day. From these results, it is more beneficial to machine transplant the older seedlings over than 30-day for delayed transplanting.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.2
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• pp.183-192
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• 2004

The effect of eight varieties of grain and forage type whole crop rice (Oryza sativa L Japonica) each harvested at four stages of maturity were investigated for morphology and yield, proportion of botanical fractions, fermentatability and chemical composition in an $8{\times}4$ factorial experiment. All crops were sown in 1997 at Saitama Prefecture, Japan under identical condition and harvested on 10, 22, 34 and 45 days after flowering in 1998. Total DM yield of forage type varieties was similar to that of the highest yield of grain type varieties. However, while yield of forage type varieties was attributed to higher proportion of straw than head, the reverse was in the case of grain type varieties. Yield in line with the proportion of head increased (p<0.001), but in contrast proportion of straw decreased (p<0.001) with the increase in maturity. Silage fermentability of grain type varieties was better than forage type varieties. Fermentability improved with the increase (p<0.001) in maturity suggesting that the moisture content should be reduced to improve fermentation quality. Forage type varieties contained higher (p<0.001) ash, crude fat (EE), organic cell wall (OCW) and acid detergent fiber (ADF), but contained lower crude protein (CP), organic cell content (OCC), CP in OCC and nitrogen-free cell wall extract (NCWFE) than the grain type varieties. The ash, CP, EE, Oa (60% digestible OCW), Ob (40% digestible OCW), OCW, ADF and acid detergent lignin (ADL) decreased (p<0.001), but OCC and NCWFE increased (p<0.001) with the increase in maturity. It is concluded that stage of maturity not only increases yield and proportion of head, but also improved the fermentation quality and increases quality chemical composition (except CP) of whole crop rice. Forage type varieties may be as good as grain type varieties in terms of yield, but fermentation quality and chemical composition may not be as good as that of grain type varieties.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.2
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• pp.143-148
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• 1999

Soil moisture condition is an important limiting factor in growth and yield in rice culture. The purpose of this study was to compare the influence on the growth, yield and Quality of rice subjected to soil moisture stress (SMS) at different growth stages. Ajaponica rice cultivar, Dongjinbyeo, was cultured under flooded conditions in a plastic container filled with silty loam soil. The container was subjected to SMS until the initial wilting point (IWP) coincided with about 10% in soil moisture content and about-200 kPa in soil matric potential, and was then irrigated again, at 6 and 5 of main growth stage in 1996 and 1997, respectively. At maturity, the plant height, tiller number, leaf area and top dry weight were decreased more in SMS treatments at the early stage than the late stage. The averaged yield index of SMS to control in both years was lowest at meiosis (62.5%), which primarily resulted from lower percent ripened grain and 1,000 grain weight, and second＇ reduced the spikelet number per panicle and panicle number per hill, and followed at tillering stage (68.5%) which resulted from the lower production in tiller number and top dry matter during and after SMS treatment. The percent-age of read rice in SMS plants varied with the treatment stage as order of lower at meiosis (44.0%), heading (53.9%), panicle initiation (70.1%), tillering (72.1%), ripening (75.8%) and 5 days after transplanting (DAT) (79.0%). Protein content in brown rice was slightly larger in SMS at late growth stage than the control, while the contents of fat and ash differed very little between SMS and control. Contents of Mg and K and Mg/K in brown rice with SMS were lower at some treatment stages such as at ripening or panicle initiation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.spc1
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• pp.51-55
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• 2005

The characters associated with the quality of rice and the factors involved in the production of high quality rice as the proper transplanting time was examined at Unbong the southern alpine area from 2002 to 2004. The rice cultivars tested were Samcheonbyeo (Early maturing one), Sangmibyeo (Sub-early maturing one). The number of spikelets were increased as earlier the transplanting date in all cultivar, The ripened grain rates were highest transplanted on May 21 for Samcheonbyeo, and May 1 for Sangmibyeo. The highest head rice yield was obtained when transplanted on May 21 and May 1 for Samcheonbyeo and Sangmibyeo, respectively. The optimum transplanting dates according to maturing types with respect to the yield of head rice, ripened grain rates and rice quality were May 21 for early maturing type and May 1 for sub-early maturing type.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.13-13
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• 2017

By the progress of genome sequencing, infrastructures for marker-assisted breeding (MAB) of rice came to be established. Fine mapping and gene isolation have been conducted using the breeding materials derived from natural variations and artificial mutants. Such genetic analysis by the genome-wide dense markers provided us the knowledge about the many genes controlling important traits. We identified several genes or quantitative trait loci (QTL) for heading date, blast resistance, eating quality, high-temperature stress tolerance, and so on. NILs of each gene controlling heading date contribute to elongate the rice harvest period. Determination of precise gene location of blast resistance gene pi21, allowed us to overcome linkage drag, co-introduction of undesirable eating quality. We could also breed the first practical rice cultivar in Japan with a brown planthopper resistance gene bph11 in the genetic back-ground of an elite cultivar. Discovery of major and minor QTLs for good eating quality allowed us to fine-tune of eating quality according to the rice planting area or usage of rice grain. Many rice cultivars have bred efficiently by MAB for several traits, or by marker-assisted backcross breeding through chromosome segment substitution lines (CSSLs) using genetically diverse accessions. We are also systematically supporting the crop breeding of other sectors by MAB or by providing resources such as CSSLs. It is possible to pyramid many genes for important traits by using MAB, but is still difficult to improve the yielding ability. We are performing a Genomic Selection (GS) for improvement of rice biomass and grain yield. We are also trying to apply the genome editing technology for high yield rice breeding.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.1
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• pp.70-75
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• 2010

In Korea, standard N application level was amended from 110 to 90kg per ha for high quality rice production in 2005. So far, N application method, however, has not been considered for yield and quality based on changed standard N application level. Therefore, this experiment was conducted to find out more efficient N application method for improving rice quality or labor saving under the amended standard N application level with several varieties at three site (Suwon, Iksan, and Milyang) for two years from 2005 to 2006. Top dressing of N at 15 days before heading compared to the standard (25 days before heading) showed improved rice qualities such as 1000 grain weight and head rice ratio without changing rice yield and protein content of brown rice. In addition, there were no significant differences in yield and quality between different N split application of 70-0-30% and 50-30-20%, indicating that the former would be useful for labor saving without yield decrease and quality deterioration.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.3
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• pp.382-390
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• 1995

To compare the rice yield and grain quality characteristics between mature(MPF) and reclaimed paddy field(RPF), grain yield and its components, some physicochemical properties of rice grain and palatability of cooked rice were investigated for Dongjinbyeo grown at three different locations of mature and reclaimed paddy field, respectively, in south western part of Korea. Variation of culm length in mature paddy area was larger than that in reclaimed saline area. Panicle number per m$^2$ in RPF was more then that in MPF but grain number per m$^2$, filled grain ratio and 1, 000-grain weight in RPF were lower than those in MPT. Average yield of milled rice in RPF was 12% lower than that in MPF (5.l1t /ha). Daejeon showed the highest yielding among MPF and Yeongam reveald the highest grain production among RPF. RPF rices had slightly higher carbohydrate content and alkali digestibility but lower protein, fat and amylose content compared with MPF rices. RPF rices also exhibited higher mineral contents, Mg/K ratio, peak and hot viscosity compared with MPF rices. RPF rice showed slightly poor apparent grain quality but a little better eating quality of cooked rice compared with MPF rice.