• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.3
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• pp.193-203
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• 2019

The aim of this study was to analyze the relationship between rice yield and climate elements in Daegu (southern plain area) and Andong (inland mountainous area) regions. Over the past 20 years, rice yield has increased in both regions. The rice yield of middle and mid-late maturing cultivars in the recent 5 years increased by about 10% and 18%, respectively, compared to that produced in the early 2000s in the Daegu region. In the Andong region, the rice yield of mid-late maturing rice cultivars in the recent 5 years was higher by about 7% than that of the early 2000s. The number of panicles per hill and grain ripening rate significantly affected rice yield in mid-late maturing cultivars. In addition, the grain weight and grain ripening rate significantly affected rice production in middle maturing cultivars grown in the Daegu region. With regard to the middle maturing cultivars, the relationship between grain weight and rice yield had a positive significant correlation in both regions. To understand the effect of climate factors on rice yield, the milled rice yield of several rice cultivars produced over the past 20 years (1999-2018) at both locations, Daegu and Andong, were evaluated. The rice yields increased owing to long sunshine duration during the grain filling stage in the Daegu region. In Andong, rising maximum temperature during the vegetative stage increased rice yield of early and mid-late maturing cultivars. Long sunshine hours increased yield of mid-late maturing cultivars in both regions.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.354-354
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• 2017

Rice grain yield is determined by crop dry matter production that is sensitive to temperature. Our objective was to determine whether the difference in temperature between years had an impact on the relationship between yield components and grain yield. Field experiments were conducted under machine transplanting cultivation by using yield data of two japonica rice varieties, Odaebyeo (early maturing) and Nampyeong (mid-late maturing), in 2013 to 2016 in Suwon, Korea. Plant height, dry weight, and yield components were examined by analysis of variance, correlation. The milled rice yield of the two varieties were the highest in 2016, however the lowest yields were observed in the different years. In 2016, Odaebyeo produced $0.96t\;ha^{-1}$ greater milled rice yield than in 2015, and Nampyeong produced $1.11t\;ha^{-1}$ greater yield than in 2013. The correlation analysis indicated that spikelet per panicle (R = 0.53) was associated with grain yield of Odaebyeo. In Nampyeong, biomass at heading date (R = 0.74), 1000-grain weight (R = 0.71), spikelet per panicle (R = 0.58), and panicle number per $m^2$ were associated with grain yield. Sink size (spikelet number per $m^2$) of the two varieties responded to accumulative temperature from transplanting to panicle initiation stage. In this experiment, optimal accumulative temperature before panicle initiation has effect on increased spikelet number and/or number of panicle that were mainly responsible for yield difference. Rice production research to increase grain yield should consider all yield components, but increased emphasis on biomass production before heading is also necessary as well as grain ripening conditions.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.917-919
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• 2003

This paper demonstrates that RADARSAT ScanSAR data can be an important data source of radar remote sensing for monitoring crop systems and estimation of rice yield for large areas in tropic and sub-tropical regions. Experiments were carried out to show the effectiveness of RADARSAT ScanSAR data for rice yield estimation in whole province of Guangdong, South China. A methodology was developed to deal with a series of issues in extracting rice information from the ScanSAR data, such as topographic influences, levels of agro-management, irregular distribution of paddy fields and different rice cropping systems. A model was provided for rice yield estimation based on the relationship between the backscatter coefficient of multi-temporal SAR data and the biomass of rice.

• Research in Plant Disease
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• v.13 no.1
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• pp.20-23
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• 2007

We investigated the first symptom emerging date of rice bacterial leaf blight disease during four years from 2002 to 2005. The disease occurrence date was earlier 20$\sim$30 days in 2005 than that of 2002. The damage in different rice growth stage by the bacterial disease on rice yield and grain quality in southern part of Korea was examined. The disease decreased rice yield following by increased infection rates. Slight loss in rice yield and brown head rice rate were observed at below 10% level of infected leaf area, while over 25% infected leaf area caused the significant decrease in rice yield and brown head rice rate. More than 50% of the infected leaf area rate caused 29% yield reduction in case of infection at panicle formation stage and 18% of brown head rice rate. Cooked rice quality was also affected in the diseased rice by damage in palatability score and viscosity.

• Plant Resources
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• v.6 no.2
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• pp.134-139
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• 2003

This study was conducted to investigate the relationships between yearly variations of meteorological elements and yearly variations of productivity in rice. In addition, correlation coefficients among yield and yield components were used to find out the relationships between meteorological elements and productivity. Yearly variation of the mean air temperature in May was large with coefficients of variation(C.V.) of 25.0%, but the variation of the duration of sunshine in May were relative small. No. of panicles per hill and 1,000 grains wt. of brown rice were great with C.V. of 21.1, 19.7%, respectively, brown rice yield show more or less C.V. of 5.5% and milled rice show still less variation. Correlation coefficients between temperatures in period of cultivation from May and yield were positive correlations. Correlation Coefficients between precipitation in period of cultivation from Sep. to Oct. and yield are positive correlations. Correlation coefficients amount the panicle length, no. of panicles, no. of spikelets, ratio of ripened grains, 1,000 grains wt. of brown rice, milled rice yield, brown rice yield and milled rice yield were positively significant at the level of 1 %, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.3
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• pp.199-206
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• 2004

Typhoon "MAEMI", happened in September 2003, hit the great damage to Gyeongnam province area. Especially, rice plant was lodged or severe leaf damage was caused. This study was conducted to find out the extents of leaf damage among different rice cultivars, and to evaluate rice yield and eating quality due to leaf damage after typhoon. Rice cultivars torn off over half of the flag leaf length (FLL) were one medium-late maturing cultivar (Donginl), medium maturing cultivar (Yeonganbyeo), eight early maturing cultivars (Samcheonbyeo, Jounghwnbyeo, Munjangbyeo, Taebongbyeo, Odaebyeo, Samhaegbyeo, Sobaegbyeo, Sinunbongbyeo), two long-il type cultivars (Samgangbyeo, Namcheonbyeo), and three special use cultivars (Heukseonchalbyeo, Jinbuchalbyeo, Yangjobyeo). Cultivars torn off below 1/10 FLL were eight medium-late maturing cultivars (Chucheongbyeo, Daecheongbyeo, Saechu cheongbyeo, Donganbyeo, Daeyabyeo, Hwamyeongbyeo, 방eongsanbyeo, Dongjinbyeo) and two medium maturing cultivays (Donghaebyeo, Gumobyeo2). The rest cultivars were tore off by 1/10∼1/2 ELL. In yield components, the longer was flag leaf damage, the lower was ripened grain ratio, grain weight and brown/rough rice ratio, which was severly impacted to late than to ordinary season cultivation. However, rice yield did not decrease up to tearing by 1/10 ELL. Head rice ratio decreased from flag leaf tearing over 1/10 ELL in late season cultivation. The longer was flag leaf damage, the lower was eating quality, which could not show significantly different.

• Korean Journal Plant Pathology
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• v.14 no.6
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• pp.720-724
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• 1998

Open-top field chamber study was carried out to investigate effect of ambient ozone level on the yield of rice cultivar 'Dongjin' in Kwangyang area located in the vicinity of the industrial complex of Yechon petrolium refinery and chemical works or Kwangyang Iron and Steel works during the summer of 1997. mean ozone concentration of ambient air during daytime (9:00∼17:00) was revealed to exceed over 40 ppb which is defined to be a critical level causing plant injury and yield reduction in Europe. Yield component analysis showed that there was no significant difference in rice yield between ambient air and charcoal-filtered air. The results suggest that the ambient ozone levels during the exposure period had no effect on yield reduction of rice cultivar 'Dongjin' and it is likely that the cultivar is tolerant to ambient ozone levels.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.184-184
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• 2017

Organic matter is very important and essential factor to maintain productivity of paddy field. But as meat consumption and the demand of grain increase, the demand of forage also increased gradually in Korea. So the amount of organic matter in paddy field have been declined gradually by the reduction of return of rice straw for the forage use for cattle. There is not enough alternative resources for forage, we guess this trend of organic matter decline in paddy field would continue for the time being in Korea. So this study was performed to confirm the variation of organic matter and change of rice yield to select suitable rice cultivars which yield reduction is small in condition of organic matter decrease in paddy field. To confirm the change of rice growth and yield in condition of organic matter decrease in paddy field, we transplanted 10 rice cultivars which yield reduction are small in low fertilizer condition. We transplanted it Buan where double cropping of winter barley continues several years on June 10. Planting density were $70plants/3.3m^2$ Fertilizer amount was $N-P_2O_5-K_2O=9-4.5-5.7kg/10a$ and fertilizer split application of nitrogen was basal-tillering stage-panicle initiation = 50-20-30%. And in the other cultivation management, we observed rice standard culture of NICS. In paddy field where withdraw straws of barley and rice, the organic matter content showed tendency to decrease as the years go on. During rice cultivation season, organic matter decreased little by little, but it increased again after rice harvest season. Rice yield was more in order of Sodami, Chunghaejinmi and Saenuri. We judge that there is an advantage in rice yield of rice cultivars which have later heading date because of suitable ripening temperature. Although Sobibyeo and Shindongjinbyeo showed high yield, head rice yield decreased severely owing to chalky and cracked rice.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.335-335
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• 2017

Recently NERICA (New Rice for Africa) was developed by a crossing of African rice (Oryza glaberrima Steud.) and Asian rice (Oryza sativa L.) in West Africa, and is considered to be drought resistant, but drought resistance of NERICA and differences between Asian rice are not clarified enough. In this research, NERICA (four cultivars and two lines), Asian rice (three cultivars and sativa parent of NERICA) and African rice (glaberrima parent of NERICA) were cultivated in the field in Shizuoka University under drought and traits of each cultivar and line relevant to drought resistance, stomatal conductance by porometer, soil water content of individual depths by TDR method, SPAD values by SPAD meter and leaf thickness by micrometer, were measured and compared with dry matter production and yield. Effects of compost were also compared among sativa parent, one NERICA cultivar and two NERICA lines. Glaberrima parent showed highest top dry weight. One NERICA line, one drought resistant Asian rice cultivar and sativa parent, showed higher top dry weight and yield (ear weight) than other Asian rice cultivars and NERICA cultivars and line tested. Compost tended to increase top dry weight and yield in one of NERICA line and sativa parent. But in one NERICA cultivar and line, top dry weight and yield were not increased. In one of Asian rice, one of NERICA line and sativa parent that showed high top dry weight and yield, stomatal conductance was high. On the contrary the glaberrima parent and in other NERICA cultivars and line it was low. In sativa parent compost increased stomatal conductance but in NERICA cultivar and lines it was not. Among cultivars and lines that showed high top dry weight and yield sativa parent and one of NERICA line SPAD value and leaf thickness were high but in one of Asian rice and glaberrima parent they were low. Cultivar and line differences in yield and top dry weight among Asian rice and NERICA were significantly correlated with those in stomatal conductance ($r=0.778^{**}$ and $r=0.654^*$, respectively) and those in leaf thickness ($r=0.600^*$ and $r=0.640^*$, respectively). In Asian rice cultivars average soil water content was significantly correlated with yield ($r=0.886^*$) but in NERICA cultivars and lines it was not significant correlated (r= -0.256). Cultivar and line differences in leaf thickness were significantly correlated with SPAD value ($r=0.773^{**}$). In Asian rice cultivars it was significantly correlated ($r=0.962^{**}$), but in NERICA cultivars and lines it was not significantly correlated (r=0.559). Asian rice cultivars tended to consume soil water to increase yield but in NERICA cultivars and lines the tendency was not clear. Correlation between SPAD value and leaf thickness was different between Asian rice and NERICA cultivars and lines, and in Asian rice cultivars it was significantly correlated but in NERICA cultivars and lines it was not significant. Importance of maintaining high stomatal conductance by high leaf thickness was clarified.

• 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.