• Transactions of Materials Processing
• /
• v.14 no.4 s.76
• /
• pp.351-359
• /
• 2005

The semi-solid processing is now becoming of great interest for the production of various parts by pressure die casting. Also, the rheo-casting has been substituted for thixo-casting, because the rheo-casting can control the solid particles to globular and non-dendritic solid phase. In the rheo-casting process, the important thing is to control the solid particles behavior in semi-solid materials. So in this paper, to control solid particles behavior in semi-solid materials, we experimented about the die filling tests during the semi-solid die casting in 0.3, 0.4, 0.5 and 0, 6 solid fraction. The die filling in semi-solid die casting were simulated by MAGMA soft/thixo module. By the die filling tests and computer simulation, the effect of solid particles behavior in rheology flow had been investigated.

• Korean Journal of Breeding Science
• /
• v.40 no.3
• /
• pp.291-294
• /
• 2008

Amylogram properties such as peak viscosity, hot viscosity, cool viscosity, breakdown, pasting consistency and setback were investigated by the Rapid Visco Analyzer and interpreted by the relationship among amylogram properties according to the varietal groups classified by the rapidity of grain filling (RGF) which was calculated by the percentage of grain weight at 15 days after heading to 40 days after heading. The 164 rice recombinant inbred lines from the cross of Milyang23 and Gihobyeo were used to get the basic information regarding the amylogram properties. The used recombinant inbred lines could be grouped into 4 varietal groups such as slow maturing (less than 40% of RGF), mid-slow maturing (41-60% of RGF),mid-fast maturing (61-80% of RGF), and fast maturing (more than 81% of RGF) groups based on the RGF. The peak viscosity and setback showed regular tendency according to the varietal groups classified by the RGF. Positive significant correlations were found between pasting consistency and setback, however negative significant correlations were found between breakdown and setback in all varietal groups.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.60 no.2
• /
• pp.146-152
• /
• 2015

Early-maturing Korean Japonica cultivars and Jungmo1024 were used as plant materials to evaluate hightemperature tolerance during grain filling stage. National Institute of Crop Science (NICS) in Korea developed Jungmo1024, a mutant line from Namil (wild type) treated by using sodium azide (SA) as mutagen. To evaluate high-temperature tolerance, all cultivars were exposed to high-temperature (day $31.5{\pm}2.5^{\circ}C$/ night $27.5{\pm}1.3^{\circ}C$) and ordinary temperature (day $27.5{\pm}1.8^{\circ}C$/ night $24.7{\pm}1.6^{\circ}C$) during grain filling stage. In these conditions, we performed compared evaluation of grain shape such as length and width and grain quality by using a 1625 Cervitec grain inspector. High-temperature during grain filling stage caused decrease of grain shape. In grain shape such as length and width, the decrease rate of width (average 6.3%) was higher than the decrease rate of length (average 1.3%). Hence, high-temperature affected width of grain than length of grain. In addition, high-temperature showed a decided difference in rate of head rice between ordinary temperature (average 76.3%) and high-temperature (average 13.3%).As a result, Taebong, Ungwang, Manan, and Jungmo1024 seemed relatively a decent high-temperature tolerance than other cultivars. Especially, Jungmo1024 seemed remarkable rate of head rice (average $34.4{\pm}6.2%$) than other cultivars under high-temperature. It is considered that a genetic trait of Jungmo1024 can be useful to improve breeding for high-temperature tolerance.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 1986.06a
• /
• pp.24-25
• /
• 1986

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.28 no.1
• /
• pp.58-75
• /
• 1983

The effects of air temperature on the grain filling stage of indica-japonica crosses were studied in artificial temperature-controlled cabinets, using Indica-Japonica crosses (Suweon 264, Suweon 258 and Milyang 29), Indica IR 36 and Lengkwang) and a Japonica rice (Jinheung). The optimum temperature to achieve maximum grain weight during the grain-filling stage was $26/18^{\circ}C$ for all varieties. Within the temperature range of 13 to $28^{\circ}C$, the grain filling period was shorter as the temperature was increased. At the highest temperature $(32/24^{\circ}C)$ the upper-position grains ("special spikelets") of IR 36 required 13days after flowering to reach the maximum weight, in Jinheung 23 days, in indica-japonica varieties (Suweon 264, Suweon 258, and MiIyang 29) 18 days, and in Lengkwang, 23 days. In the case of Lengkwang, at $32/24, \;29/21^{\circ}C$ and $26/18^{\circ}C$temperature range the upper-position grain also required same 23 days after flowering to reach the maximum weight. At the lowest temperature range of $17/9^{\circ}C$, Jinheung required 68 days and Lengkwang 53 days after flowering to reach maximum grain weight. The whole panicle took 10 to 15 days later than the special spikelets to reach the maximum weight. At lower-than-optimum temperature range $(l7/9^{\circ}C\;and\;20/12^{\circ}C)$, all IR 36 plant died within 15 days after flowering. In the case of indica-japonica varieties all plants died within 15 days only at $17/9^{\circ}C$. There were more chalky grains when the temperature was higher and lower than optimum. The highest and lowest temperature range produced dead rice (black and dark red rice). Lower than optimum temperature ranges $(17/9^{\circ}C\;and\;20/12^{\circ}C)$ affected grain quality (length, width and depth) at these temperature ranges, grains were shorter, narrower, and thinner than grains at the optimum temperature of $26/18^{\circ}C$. With regared and the effects of temperature on frequency of grain weight at grain filling stage of indica variety IR 36, the highest $(32/24^{\circ}C)$ and lowest $(23/15^{\circ}C)$ temperature ranges matched the frequency of grain weight curves. In Japonica variety Jinheung, at the three temperature ranges, that is, lowest $(17/9^{\circ}C)$ highest $(32/24^{\circ}C)$ and optimum $(26/18^{\circ}C)$, the frequency of grain weight curve showed very different patterns, In the case of indica-japonica variety Suweon 258, the frequency of grain weight curve was midway between that of IR 36 and Jinheung. Jinheung.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.60 no.3
• /
• pp.266-272
• /
• 2015

High temperature impairs rice grain yield and quality. To understand the effect of high temperature on leaf physiological activity and grain filling, two cultivars of rice that Dongan and Ilpum were exposed to high temperature during ripening stage. Grain filling rate, perfect grain ratio and grain weight of high temperature ($27^{\circ}C{\pm}4^{\circ}C$) treated both rice cultivars were decreased than those of control temperature ($22^{\circ}C{\pm}4^{\circ}C$) treated. The reduction rates of grain filling ratio, perfect grain ratio and grain weight of high temperature treated to control treated rice were higher in Ilpum than Dongan. Chlorophyll contents of rice leaves under high temperature at early ripening stage were higher than those of control temperature, but those were slowly decreased with no difference between temperature treatment since at mid ripening stage. Although chlorophyll a/b ratio under high temperature was decreased from heading to 15 days after heading, that was gradually increased since 15 days after heading. Protein concentrations of rice leaves for ripening stage was a similar pattern with chlorophyll changes. The rate of photosynthesis at 14 days after heading under high temperature was higher than those of control temperature, but there was no difference at those of 7 and 34 days after heading between two temperature treatment. Free sugars under high temperature treated leaves were lower than control temperature. Consequently, these results exhibit that high temperature accelerate leaf physiological activity as chlorophyll synthesis and photosynthesis rate unlike the deterioration of grain filling.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2017.06a
• /
• pp.142-142
• /
• 2017

Wheat (Triticum asetivum L.) is one of the major grain crops worldwide. The reduced productivity ascribed by adverse environment is increasing the risk of food security. Wheat cultivars have been actively released by public side since 1960s in Korea. Each variety has been developed for superior regional adaptation, pest resistance and mostly high yield. Heat stress tolerance is one of the major parameters that threaten wheat production in Korea. Heat stress during grain filling period has been conceived as critical level and directly influences on wheat production. We evaluated 11 common wheat cultivars ("Baegjoong", "Dajung", "Goso", "Hanbaek", "Jokyoung", "Joeun", "Jopum", "Keumgang", "Olgeuru", "Sinmichal", "Uri") that were exposed to abnormally high temperature during the grain filling period. Each plant was grown well in a pot containing "Sunshine #4" soil in controlled phytotron facility set on $20^{\circ}C$ and 16 h photoperiod. At 9 day-after-anthesis (DAA9), plants were subjected to a gradual increase in temperature from $20^{\circ}C$ to $33^{\circ}C$ and maintained constantly at $33^{\circ}C$ for 5 days. After the treatment, plants were subjected to gradual decrease to normal temperature ($20^{\circ}C$) and continue to grow till harvest. Seeds were harvested from each tiller/plant. Total chlorophyll contents decrease level as well as grain parameters were measured to evaluate varietal tolerance to heat stress. We also divide each spike into five regions and evaluate grain characteristics among the regions in each spike. The obtained results allow us to classify cultivars for heat stress tolerance. The pedigree information showed that typical wheat lines provide either tolerance or susceptible trait to their off-springs, which enable breeders to develop heat stress tolerance wheat by appropriate parental choice.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2004.10a
• /
• pp.664-667
• /
• 2004

The semi-solid processing is now becoming of great interest for the production of various parts by pressure die casting. Also, the rheolory casting has been substituted for thixo casting, because the rheology casting can control the solid particles to globular and non-dendritic solid phase. In the rheology casting process, the important thing is to control the solid particles behavior in semi-solid materials. So in this paper, to control solid particles behavior in semi-solid materials, we experimented about the die filling during the semi-solid die casting in 0.3, 0.4, 0.5, 0,6 solid fraction. The die filling in semi-solid die casting were simulated by MAGMAsoft/thixo module. By the die filling tests and computer simulation, the effect of solid particles behavior in rheology flow had been investigated.

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
• /
• 2011.11a
• /
• pp.16-18
• /
• 2011

Evaluation of climate change on the rice productivity was conducted using crop growth simulation model, where Odae, Hwaseong, Ilpum were used as a representative cultivar of early, medium, and medium-late rice maturity type, respectively, and climate change scenario 'A1B' was applied to weather data for future climate change at 57sites. When cropping season was fixed, rice yield decreased by 4~35% as climate change which was caused by poor filled grain ratio with high temperature and low irradiation during grain-filling. When cropping season was changed, rice yield decreased by only 0~5% as climate change which was caused poor filled grain ratio with low irradiation during grain-filling period. However, this irradiation decline was less than when cropping season was fixed. Therefore, we need to develop rice cultivars resistant to low irradiation which can maintain high filled grain ratio under poor irradiation condition, and late maturity rice cultivars whose growing period is longer than the present medium-late maturity type.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.38 no.5
• /
• pp.425-431
• /
• 1993

Temperature effects on the grain filling of winter barley(CV. Gangbori, Olbori and Suwon 18) were studied in controlled environments under three day /night temperature regimes (viz. 25/20, 20/15 and 15/10$^{\circ}C ) and at three stages of development, viz. Vegetative, spike development and grain filling stages. Physiological maturity times to the temperature regimes were observed at 53 to 57 days after heading at 15/10$^{\circ}C , 43 to 45 days and 32 to 33 days at 20/15$^{\circ}C and 25/5$0^{\circ}C$, respectively. When plants were grown in 25/20$^{\circ}C during the spike development stages, the number of spikes per plant and grains per spike decreased by 39% and 41% respectively compared with 20/15$^{\circ}C of day / night temperature. The effect of high temperature on grain weight was not significant in all growth phases except post-anthesis where grain weight decreased by 30%. Therefore, the most important temperature effects were round during the spike development stages.