• Plant Resources
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• v.7 no.2
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• pp.141-146
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• 2004

Frequent occurrence of off-type plants in a given cultivar has been a serious problem in both breeder's and farmer's fields. An experiment was designed to examine the differences in rate of occurrence of off-type plants among Tongil-type cultivars (high yielding cultivars derived from indica/japonica hybridization) from which the possible cause of higher occurrence of off-type plant in a specific cultivar was deduced. Among five Tongil-type cultivars examined for morphological variant in the field, only one cultivar, Dasanbyeo, had off-type plants. When analyzed with SSR markers, off-type plants showed different band patterns from original cultivar, having several extra bands in addition to cultivar-specific band, suggesting that off-type plants were originated from Dasanbyeo, rather than originated from mixing or mishandling of seed materials with other cultivars. The possible cause of off-type occurrence seems to be natural pollination with other cuItivars adjacent to the original cultivar during seed multiplication. This was supported from the observation that self-crossed progeny of the off type plants showed a wide range of variation of agronomic traits which could not be observed when there was a smaller introduction of genes to the fixed germplasm as happened in the case of cultivar mutation. Another evidence supported this idea that Dasanbyeo showed much of difference in floral organ and behavior to other cultivar to be subjected to higher out-crossing than other cultivars examined.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.21 no.1
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• pp.52-56
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• 1976

60 rice cultivars were surveyed for the posses of C and A complementary genes which is responsible to the anthocyan colouration. Most of Japonica derived cultivars belong to O group which do not have either C or A gene, and a few belong to C group which has C gene. Indica derived latest cultivars belong to A group which has A gene.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.4
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• pp.420-427
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• 1995

This study was carried out to investigate heterosis in photosynthetic characteristics and yield of F$_1$ hybrid rice using genetic cytoplasmic male sterile lines. Two F$_1$ hybrid rices, HR7028A/Yongmoonbyeo and IR54756A/Yongmoonbyeo, showed heterobeltiosis in dry weight and leaf area at the heading date and at the 20 day after heading. HR7028A/Yongmoonbyeo showed heterobeltiosis and IR54756A/Yongmoonbyeo showed heterosis in chlorophyll content and RuDPCase activity in flag leaf, T-sugar and starch content in stem, and $CO_2$ fixation at the 20 day after heading as well as at the heading date. HR7028A/Yongmoonbyeo showed heterobeltiosis in number of panicles and grains per panicle, and IR54756A/Yongmoonbyeo had heterobeltiosis in number of panicles per plant. As results, heterobeltiosis of HR7028A/Yongmoonbyeo in yield was 11% and that of IR54756A/Yongmoonbyeo was 4%.

• Korean Journal of Environmental Agriculture
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• v.1 no.2
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• pp.129-133
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• 1982

This study was conducted to find out the resistance of rice varieties to ozone gas. Thirty eight rice varieties were exposed to 0.3 ppm $O_3$ gas for 3 hours. Damage symptom, percentage of destroyed leaf and chlorophyll contents were observed after $O_3$ fumigation. The results obtained are as follows. 1) Typical symptom of $O_3$ damage appeared to greyish subtle spots in Japonica type and redish brown subtle spots in Indica-Japonica hybrid type within rice leaf vein. 2) Resistant varieties to $O_3$ gas were Palgwangbyeo, Seokwangbyeo and Milyang 30, while sensitive ones were Gwanakbyeo, Jinjubyeo and Hankangchalbyeo. 3) Chlorophyll damage of rice leaves were higher in Nongbaeck, Dobongbyeo, Palgeum, Jinjubyeo than in Milyang 21, Podgwangbyeo, Josaeongtongil, Honamjosaeng, Hwanggeumbyeo. 4) The amount of chlorophyll damage showed highly significant positive correlation with that of leaf destruction.

• Korean Journal of Breeding Science
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• v.42 no.3
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• pp.231-235
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• 2010

'Jopung' (Avena sativa L.), a winter oat for forage use, was developed by the breeding team at the Department of Rice and Winter Cereal Crop, NICS, RDA in 2009. It was derived from an original cross between the $F_1$ hybrid of 'Early80' and 'PA202-210-S' and 'Walken' in 1999. Subsequent generations followed by the cross were handled in bulk and pedigree selection programs at Suwon and Yeoncheon, respectively. A line, 'SO99006-B-YB-29-Y1', was selected for earliness and good agronomic characteristics and designated as a line name of 'Gwiri65'. The line 'Gwiri65' was subsequently evaluated for earliness and forage yield in four different locations, Yesan, Iksan, Kimjae, and Jeju, from 2007 to 2009 and finally named as 'Jopung'. Over 3 years, the average forage dry matter yield of cultivar 'Jopung' harvested at milk-ripe stage was $17.3MT\;ha^{-1}$, compared with $13.6MT\;ha^{-1}$ of check cultivar 'Swan'. The silage quality of 'Jopung' was superior to the check cultivar 'Swan' in crude protein content, and was similar to the check cultivar in percent total digestible nutrients (TDN). Cultivar 'Jopung' is suitable primarily for winter planting in the southern regions of Korean peninsula.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.spc1
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• pp.58-66
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• 2006

The rice quality related traits including physico-chemical traits were evaluated with one hundred sixty-four MG RILs derived from the cross between Milyang 23, Indica/Japonica hybrid type, and Gihobyeo, Japonica type. The variation distribution of all traits examined approximately fit normal distribution and transgressive segregants over parents were observed for all traits. The occurrence of such transgression could be associated with the interactions of complementary QTL alleles from two parents. However in this study, it could not be concluded that our results of segregation were due to either complementary gene effects or overdominance of a major gene. These factors should be verified by further studies. Correlations between traits were evaluated by regressing phenotypic values of one trait on those of another traits. There are highly significant correlation between grain thickness with grain width, white core and white belly. But between white belly and alkali digestion value showed highly negative significant correlation. Contents of protein showed highly negative correlation with amylose and Mg/K ratio but showed highly correlation with K and Fat contents. Hardness of cooked rice showed highly correlation with adhesiveness, elasticity, gumminess, chewiness.

• Korean Journal of Agricultural Science
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• v.40 no.2
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• pp.123-129
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• 2013

An experiment was conducted to evaluate the effects of nitrogen supplementation through urea-molasses multinutrient block (UMMB) on the performance of dairy cows fed good quality forage based diets with rice straw as a night feeding. A total of 10 multiparous crossbred dairy cows in their early lactation were grouped into two categories based on their breed, parity, body weight, milk yield, milk fat and protein contents and daily fed a chopped CO-3 grass (Pennisetum purpureum ${\times}$ Pennisetum americanum; hybrid Napier) ad-libitum, 1 kg of dairy cow concentrate feed during the day time and 5 kg of rice straw (dry matter basis) at night as the basal diet (control) for 5 wk. In addition to the basal diet, the treatment group received 300 g of crushed UMMB daily throughout the experimental period. Cows were milked twice daily and the milk yields were recorded. Milk and feed samples were collected weekly for chemical analysis. Supplementation of UMMB had no significant effects (p>0.05) on straw intake, daily milk yield, contents and yields of milk constituents such as milk fat, protein, lactose and solids-non-fat. In addition, milk urea nitrogen content were not affected (p>0.05) by UMMB supplementation. However, numerical increments in all the parameters measured were observed during the study in cows fed diets supplemented with UMMB. It can be concluded that nitrogen supplied through UMMB had no effects on production performances of dairy cows in this study.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.1
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• pp.55-59
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• 1989

Sodium methyl arsenate has been evaluated as a male sterilizing agent for the system of producing hybrid rice seeds. The compound was the most effective at the concentration of 0.02％. When applied as a foliar spray to four rice varieties at 15 days before heading, sodium methyl arsenate has produced 99％ male sterility. But the most effective time for application of the compound was 5 days before heading because of its phytotoxic effects. Effective application volume of the compound solution has depended on the growth of the plants treated. Varietal difference on the activity of the compound has been detected.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.6
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• pp.684-696
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• 1995

A mutant for chalky endosperm and genetic male sterility (GMS) was newly developed in rice. The two characters were found to be controlled by single recessive gene which has pleiotropic effect, indicating that chalky seeds should be GMS seeds in segregating populations. Chalky seeds showed the same shape and size as normal seeds. However, starch composition of central part of endosperm was looser and shape of starch granules was rounder compared with normal endosperm, resulting in significantly lower grain weight, absolute density and grain hardness in chalky grains than in normal ones. Amylose content and gel consistency of chalky grains were much lower and harder, respectively. Male sterile plants showed much shorter plant height, poorer panicle exsertion and lesser panicle number compared with normal plants. Microspore abortion stage in pollen developmental process was observed as before meiosis. Male sterility of the mutant was stable regadless of temperature and day length. A system breeding hybrid rice using this mutant was discussed, comp ring with other systems utilizing cytoplasmic-genic male sterility(CGMS) and environment sensitive GMS(EGMS). Separation of GMS seeds in mixed seed bulks by specific gravity (1.14∼1.16g / cm3) was successful about 85∼90%. But some mixed normal plants were seemed to be easily removed by the apparent difference in growth characters at seedling stage. The highest natural outcrossing rate of this GMS line was as 17.3 % in a plot treated with 2-row pollinator, I-row GMS, and GA3 + cutting of flag leaf + pollen-scattering by rope.

• Korean Journal of Soil Science and Fertilizer
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• v.9 no.2
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• pp.83-92
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• 1976

The relationships between various nitrogen efficiencies among 57 rice cultivars grouped into three developmental categories were investigated by simple correlation with (12kg/10a) and without nitrogen fertilizer under the field condition. The relationship showed similar in a group or among all varieties of three groups. Yield among varieties showed highly significant correlation with Fe (fertilization efficiency: yield increment/nitrogen applied), E (nitrogen efficiency for yield), Ef(efficiency of nitrogen derived from fertilizer) and Eu (fertilizer use efficiency: nitrogen derived from fertilizer divided by total nitrogen applied). The E was correlated significantly and positively with harvest index (HI), percent translocation (T) of nitrogen to ear and negatively with nitrogen uptake amount (N), nitrogen concentration in grain (GN%) and in straw (SN%). The E depends almost on Ef and only inTongil group partly on Es (efficiency of nitrogen derived from soil). The Ef contributes to Fe more than Eu does (Fe = $Ef{\cdot}Eu$). It appears that Ef and Eu increased from the old group to the recommended local varieties, but only EF and Es increased markedly when rice was developed from recommended local group to Tongil line ($indica{\times}japonica$ hybrid selction). The fact that E and Fe depend more on Ef among rice varieties is very good contrast to the result that E and Fe depend more on Es and Eu respectively among soils in the previous investigatigation. The Ef appears as the most important parameter for rice varietal selection under fertilizer application system.