• Korean Journal of Breeding Science
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• v.40 no.3
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• pp.211-214
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• 2008

Haploid system by anther culture allows the development of homozygous lines when doubled. The response of anther culture to Basta (glufosinate) resistance was investigated on transgenic plants (cv. Anjungbyeo) in order to identify inheritance of bar gene associated with Basta. Most of the regenerated transgenic plants were sterile, and only a few plants produced viable seeds ($A_1$) in the greenhouse. The bar gene was analysis by PCR in basta resistant transgenic plant ($TA_0$). The transgenic seeds ($A_1$) were significantly germinated in Basta solution compared with non-transformed seeds. As a result of anther culture, in regenerated haploid plants, segregation ratio was 1:1 in five of eight cross combinations. In diploid plants, segregation ratio was 1:1 in seven of eight cross combinations. Although there was some differences in the cross combinations, most of the combinations had 1:1 segregation ratio which supports the theory. The difference may be a result of the small sample size or the difference of anther culture response caused by genotypic difference. Hence, when many cross combinations were anther-cultured the results would support the theory.

• Analytical Science and Technology
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• v.37 no.1
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• pp.12-24
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• 2024

In this study, laser-induced breakdown spectroscopy (LIBS) was used to estimate the degree of rice polishing. As-threshed rice seeds were dehusked and polished for different times, and the resulting grains were analyzed using LIBS. Various atomic, ionic, and molecular emissions were identified in the LIBS spectra. Their correlation with the amount of polished-off matter was investigated. Na I and Rb I emission line intensities showed linear sensitivity in the widest range of polished-off-matter amount. Thus, univariate models based on those lines were developed to predict the weight percent of polished-off matter and showed 3-5 % accuracy performances. Partial least squares-regression (PLS-R) was also applied to develop a multivariate model using Si I, Mg I, Ca I, Na I, K I, and Rb I emission lines. It outperformed the univariate models in prediction accuracy (2 %). Our results suggest that LIBS can be a reliable tool for authenticating the degree of rice polishing, which is closed related to nutrition, shelf life, appearance, and commercial value of rice products.

• Journal of Biosystems Engineering
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• v.22 no.4
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• pp.401-410
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• 1997

Scattering of seeds is one of the problems in the hill- dropping planters with a roller-type metering device. For crops like rice, corns and beans, the hill-dropping is own better for a high yield than the drill planting. The roller type metering device has been used for the drill planters and has many advantages. However, it has a problem of scattering of seeds when they are placed on rows. In this study a method was developed to design the roller type metering device fir the precision hill-droppings. Design parameters were derived to configure completely the geometries of the roller and brush. The method was applied to the design of the metering device of the rice seeding machines. The field test showed that the metering device designed by the method made a better performance of seed placement than that made by the precvious one. The method also can be applied to the design of metering devices for the precise hill-droppings of other crops.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.4
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• pp.373-377
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• 1997

The bird repellent, methiocarb 50% WP, has been used to reduce the bird damage in the crop field in the European countries. The bird damage occaisonally would occur in the wet direct seeded rice and in soybean field, and resulted in decreasing the crop productivity by the reduction of seedling emergence rate. In this experiment, rice seeds, Hwasungbyeo(Oryza sativa), were coated with the different application rate of methiocarb, 5, 10 and 15 per kg seed, and soybean, Taegwangkong(Glycine max), 2.5, 5.0 and 7.5g. In rice, the seeds coated with 10 and 15g of methiocarb were not lost by bird, while those with 5g and control were lost to 37 and 50% of total seeds, respectively. No damage by birds was observed in rice seedling when the coleoptile and radicle of rice were emerged at 7 days after the water seeding. The crop injury of methiocarb reducing the emergence rate of seedlings, shortening the shoot length, and decreasing the leaf number was occurred at the treated of methiocarb 15g per kg seed. In soybean, the loss of the sprouting by birds was lower in the treatment of methiocarb 7.5g per kg seed than that in both the control and the treatments of methiocarb, 2.5 and 5.0g per kg seed. No crop injury by the treatment of methiocarb was observed in all application rate.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.4
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• pp.417-420
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• 2008

This study was carried out to compare the growth and yield characteristics between bakanae diseases (Gibberella fujikuroi) infected and uninfected rice plants with different disinfection mothods. The infected rice seeds, harvested previous year, were disinfected either with prochloraz for 48 hours at $33^{\circ}C$ in germinator or 24 hours at room temperature and not disinfected. In the methods of disinfection, it is more effective in disinfected by prochloraz for 48 hours at $33^{\circ}C$ using germinator near to 0% of infection rate, followed by conventional method as 5.0% and 76% in not disinfected rice seeds. In the rice yield components among the disinfection methods, panicles were increased about 11% in the disinfected seeds using germinator for 48 hours compared to conventional method. Ripening grain rate also increased at the disinfected using germinator as $80.3{\sim}80.3%$, improved more than $4.9{\sim}5.9%$ compared to the conventional disinfection. From these results, the rice yield was $512{\sim}517\;kg/1,000\;m^2$ at the disinfected using germinator which increased more than $6{\sim}7%$ compared to the conventional disinfection.

• Journal of Practical Agriculture & Fisheries Research
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• v.13 no.1
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• pp.19-26
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• 2011

The machine transplanted rice has highly extended in the Republic of Korea due to a wage rise since 1976 and thus rice seedling raising nursery method has shifted from field into polyethylene film house. The rice seedling grown under a polyethylene film house was weak and tall because of limited sunlight and wind and so there was so complained among rice growing farmers in terms of missing hill and broken seedling after machine transplanting. In recent iron-coated seedling has reported on healthier and stronger than that of polyethylene film house. These seedlings were more stiff and thus more easy to handle during transplanting and less missing hills. The Iron-coated seed was proven to more stiff like seedling height, root growth and weight of shoot and root growth. This was more convenient during transfer of seedling raising box im machine transplanting. Thus, this study was carried out to grow a stiff and healthy seedling growth and development for machine transplanting. There were a normal seed germination and sprouting after iron-coated seeds treatment and this seedling was smaller and stiffer than that of untreated control. The leaf number and root growth of seedling which was iron-coated seeds would be better and total seedling fresh weight was greater than that of untreated control.

• The Plant Pathology Journal
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• v.16 no.4
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• pp.236-241
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• 2000

A selective agar medium was developed and tested for the isolation of Acidovorax avenae subsp. avenae, the causal bacterial pathogen of bacterial brown stripe, from rice seeds. The new selective agar medium, designated sorbitol pyroglutamic acid agar (SPA) medium, contained 0.5 g of $K_2$HPO$_4$, 3.0 g of Na$_2$HPO$_4$, 2.0 g of D-sorbitol, 0.2 g of L-pyroglutamic acid, 10.0 $m\ell$ of tween 80, 40.0 mg of victoria blue B, 15.0 g of agar, 150.0 mg of ampicillin and 25.0 mg of vancomycin per litter. Colonies of A. avenae subsp. avenae on SPA medium were smooth, round, convex, shiny, blue and 1.5-2.0 mm in diameter 4 days after incubation at 28$^{\circ}C$. Blue colored colony having dark blue zone was typical type of A. avenae subsp. avenae colonies on the medium. Mean recovery of 8 isolates of A. avenae subsp. avenae on the selective SPA medium was 95.8% in comparison to that on KB medium. The saprophytic bacteria were reduced to 97.9% on SPA medium compared to those on KB medium. Most of other rice seedborne bacteria as well as reported pathogenic bacteria were failed to grow on SPA medium. This medium was highly selective for recovering A. avenae subsp. avenae from rice seed samples, and it could be used to enhance the recovery of this bacterium from rice seed samples, which may be contaminated with large numbers of competing microorganisms.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.31 no.3
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• pp.311-317
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• 1986

To obtain the basic informations on the variation of rice grain shattering under different environmental conditions, several experiments were carried out from 1982 to 1985. The degree of grain shattering was significantly differed depending upon the harvesting time after heading in some rice varieties. It appeared that the ratio of grain shattering was greatly affected by the drying period after harvesting; the ratio of grain shattering of sun-dried seeds for 6 days after harvesting was higher than those of the just harvested seeds. Grain shattering was increased at high level of nitrogen and decreased with delay in transplanting date. Yearly differences in grain shattering was more clearly recognized in easy-shattering varieties in comparison with those of non-shattering varieties. Rice grain shattering also increased by the low temperature treatment (l7/15$^{\circ}C$, day/night) at booting stage, 5 to 11 days before heading. A rice variety, Milyang 23, belong to easy shattering group was more pronounced at the low temperature condition with shading. In general, it was always possible to classify the cultivar differences between easy-shattering and non-shattering groups regardless of any environmental condition. Thus results suggested that rice grain shattering will be largely governed by genetic factors.

• Korean Journal of Breeding Science
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• v.42 no.2
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• pp.144-150
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• 2010

The objective of this study was to map gene/QTL for photoblastism in a weedy rice (photoblastic rice: PBR) using DNA markers. Light-induced effect on germination of seeds was compared among three accessions (Oryza sativa L.), PBR, Milyang 23 and Ilpum. Results showed that PBR seeds started to show photoblastism during seed development, different from Ilpum and Milyang 23. Frequency distribution of germination in the F4 lines from crosses between Ilpum and PBR and, Milyang 23 and PBR revealed bimodal distributions suggesting that photoblastism was controlled by a few genes. Bulked segregant analysis using $F_4$ populations derived from the above two crosses was conducted to identify gene/QTL for photoblastism. Two QTL were identified on chromosomes 1 and 12 explaining 11.2 and 12.8% of the phenotypic variance, respectively. Two QTL were further mapped between two SSR markers, RM8260 and RM246 on chromosome 1, and between RM270 and 1103 on chromosome 12. It is noteworthy that two QTL for photoblastism were colocalized with the QTL for seed dormancy reported in the previous QTL studies. The clustering of two genes for photoblastism and dormancy possibly indicates that these regions constitute rice phytochrome gene clusters related to germination. Because PBR has a low degree of dormancy, a pleiotropic effect of a single gene controlling dormancy and photoblastism can be ruled out. The linked markers will provide the foundation for positional cloning of the gene.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.1009-1020
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• 1996

Direct-seeded rice can have comparable yield with transplanted rice if its inherent problems can be solved. It is a labor-saving technology and can significantly reduce production cost because seedling nursery , pulling , and transplanting are omitted. Turnaround time between cropping is reduced hence the possibility of a third annual crop. But direct-seeded rice is very vulnerable to pest attack (by birds, rats, and golden snails), desiccation, weed infestation, and prone to lodging resulting to unstable crop establishment and inconsistent yield. These problems can be solved by anaerobic seeding (sowing pre-germinated seeds under the soil). It requires precise seed placement into the soil to optimize its benefits. We developed a four-row anaerobic direct seeder (US $ 200 commercial price) for this purpose . It consist of a structural framework mounted with a drum -hopper metering device, flotation type drivewheels, spring-loaded and adjustable furrow closers, and furrow open rs, and a plastic rainguard. It can sow in line pre-germinated seeds into the soil thus permitting the use of mechanical weeders for a chemical-free weed control. Its performance was comparable with the Japanese two-row anaerobic seeder (costing US$400) in terms of seed placement and crop establishment. It was tested with five cultivars. Seeding rate varied from 38 kg/ha to 80kg/ha. Crop establishment ranged from 64 to 99 percent while grain yield varied from 3.0 t/ha to 5.4t/ha. A six-row anaerobic seeder was also developed and adapted to a powertiller for increased capacity , field efficiency , and easier operation. The anaerobic seeder is useful to farmers shifting to direct seeding to reduce rice production cost and to researchers conducting agronomic studies in direct-seeded rice. Blueprint of the machine is available free of charge from IRRI.