• Preventive Nutrition and Food Science
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• v.21 no.2
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• pp.97-103
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• 2016

In our previous study, an early-maturing variety of rice (Oryza sativa L.), Jinbu can have feature with unique green color, various phytochemicals as well as nutritive components by the optimal early harvesting, called Green Rice$^{(R)}$ (GR). The aims of the present field experiments were to evaluate the changes in the weight of 1,000 kernels, yield, and contents of proximate and bioactive compounds in Chuchung, a mid-late maturing variety, during the pre-harvest maturation of rough rice and to research the appropriate harvest time and potent bioactivity of Chuchung GR. The weights of 1,000 kernels of Chuchung GR dramatically increased until 27 days after heading (DAH). The yields of Chuchung GR declined after 27 DAH and significantly declined to 0.0% after 45 DAH. The caloric value and total mineral contents were higher in the GR than in the full ripe stage, the brown rice (BR). In the GR, the contents of bioactive compounds, such as ${\gamma}$-aminobutyric acid, ${\gamma}$-oryzanol, and ${\alpha}$-tocopherol, were much higher (P<0.05) than those in the BR, specifically during 24~27 DAH. Therefore, bioactive Chuchung GR can be produced with a reasonable yield at 24~27 DAH and it could be useful for applications in various nutritive and functional food products.

• The Plant Pathology Journal
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• v.38 no.6
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• pp.679-684
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• 2022

Rice blast is one of the most destructive diseases of rice worldwide, and the causative agent is the filamentous ascomycete Magnaporthe oryzae. With the successful cloning of more and more avirulence genes from M. oryzae, the direct extraction of M. oryzae genomic DNA from infected rice tissue would be useful alternative for rapid monitoring of changes of avirulence genes without isolation and cultivation of the pathogen. In this study, a fast, low-cost and reliable method for DNA preparation of M. oryzae from a small piece of infected single rice leaf or neck lesion was established. This single step method only required 10 min for DNA preparation and conventional chemical reagents commonly found in the laboratory. The AvrPik and AvrPi9 genes were successfully amplified with the prepared DNA. The expected DNA fragments from 570 bp to 1,139 bp could be amplified even three months after DNA preparation. This method was also suitable for DNA preparation from M. oryzae strains stored on the filter paper. All together these results indicate that the DNA preparation method established in this study is reliable, and could meet the basic needs for polymerase chain reaction-based analysis of M. oryzae.

• Journal of Crop Science and Biotechnology
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• v.11 no.1
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• pp.75-82
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• 2008

Functional stay-green is a beneficial trait that may increase grain yield through the sustained photosynthetic competence during monocarpic senescence in cereal crops. The temporal changes of photosynthesis and related characteristics throughout the grain filling period of a stay-green japonica rice "SNU-SG1" was compared in growth chamber conditions with three high-yielding cultivars(HYVs) and their $F_1$ hybrids with SNU-SG1. SNU-SG1 exhibited a typical characteristic of functional stay-green in terms of chlorophyll degradation and photosynthetic competence during grain filling. According to the photosynthesis-light response curve measured at 10 and 35 d after heading for the flag leaf, SNU-SG1 exhibited higher initial light conversion efficiency and thus higher gross photosynthetic rate at light saturation compared to HYVs. Light saturation point was not different among genotypes, ranging from 1000 to 1500 ${\mu}mol$ photon $m^{-2}s^{-1}$. Net photosynthetic rate at light saturation($P_{max}$) of the upper four leaves in SNU-SG1 was much higher and sustained longer throughout grain-filling than HYVs and $F_1$ hybrids. The sustained high photosynthetic competence of SNU-SG1 during grain filling was ascribed to the longer maintenance of high mesophyll conductance that resulted from not only high chlorophyll content and its delayed degradation but also the slow degeneration of photosystem II(PS II) as judged by chlorophyll fluorescence($F_v/F_m$) of flag leaves. $F_1$ hybrids showed slow degeneration of photosystem II similar to the male parent SNU-SG1 while chlorophyll degradation pattern close to female parents, thus exhibiting a little higher $P_{max}$ than female parents. These results suggest that SNU-SG1 has a typical functional stay-green trait that can be utilized for increasing rice yield potential through the improved dry matter production during grain filling.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.2
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• pp.221-227
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• 2011

Applications of green manures generally improve the soil quality in rice paddy in part through restructuring of soil microbial communities. To determine how different green manures affect soil microbial communities during the early stages of rice growth, fatty acid methyl ester (FAME) profiles were used to the effects of different management practices: 1) conventional farming (CF), 2) no-treatment (NT), 3) Chinese milk vetch (CMV), 4) green barley (GB), and 5) triticale in paddy field. With applications of green manures, soil organic matter was significantly higher than CF, while soil Na concentration was significantly lower compared with CF (p<0.05). Total soil microbial biomass of CMV was higher (p<0.05) than NF by approximately 31%. The highest ratio of monounsaturated fatty acid to saturated fatty acid was found in the GB plot, followed by CMV and triticale compared with CF (p<0.05), possibly indicating that microbial stress was less in GB and CMV plots. Populations of Gram-negative bacteria and arbuscular mycorrhizal fungi also were significantly higher green manures than CF (p<0.05). Our findings suggest that GB should be considered as optimum green manure for enhancing soil microbial community at an early growing stage in paddy field.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.6
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• pp.606-609
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• 2013

To investigate the effect of partial tillage seeding of hairy vetch on green manure biomass and rice yield, on-farm experiment was conducted at eco-friendly hairy vetch cultivation area located in Yesan-gun, Chungcheongnam-do. Seeding methods of hairy vetch consisted of partial tillage seeding (PTS) and broadcasting before rice harvesting (BBRH). Hairy vetch was incorporated into soil on May 18 and rice seedling was transplanted on May 26. The growths of hairy vetch before overwintering were investigated on November 11. Plant height of BBRH plot was longer than that of PTS plot, but somewhat larger number of seedling stand was found in PTS. Biomass and N production of hairy vetch were investigated on May 18. Results of the investigation showed no difference between two seeding methods. Although the seeding time was 21 days late in PTS, the biomass of hairy vetch and rice yield were equivalent to those of BBRH seeding, so we conclude that PTS could improve overwintering survival of hairy vetch in rice cropping system.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.3
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• pp.187-194
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• 2017

This study was conducted to investigate rice yield and soil chemical properties affected by incorporation levels of green barley (GB) and hairy vetch (HV). The GB and HV were applied to the pots at 500, 1,000, 1,500, and $2,000kg\;10^{-1}$ (GB500, GB1000, GB1500, GB2000, HV500, HV1000, HV1500, and HV2000, respectively), and inorganic fertilizer ($N-P-K=9-4.5-5.7kg\;10a^{-1}$) treatment as control. After rice harvesting, chemical properties of soil such as pH, OM, T-N, and available $P_2O_5$ in GB and HV treated treatments were improved over those in Control treatment. The rice yield ranged from 433 to $512kg\;10a^{-1}$ for GB treatments and 490 to $532kg\;10a^{-1}$ for HV treatments, indicating that rice yield was affected by incorporation levels of GB and HV. The rice yields in GB2000, HV1000, HV1500 and HV2000 treatments increased by 3.3, 3.1, 6.4 and 7.4% compared with Control treatment, respectively. Therefore, minimum incorporation level of GB and HV for increasing rice yield was $2,000kg\;10a^{-1}$ of GB and $1,000kg\;10a^{-1}$ of HV.

• Korean Journal of Soil Science and Fertilizer
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• v.35 no.3
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• pp.169-174
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• 2002

The aim of this study was to test a utilization possibility of hairy vetch as a green manure in rice cultivation. The effect of hairy vetch on yield and nitrogen uptake or rice was investigated for three years. The yield of rice increased by 7% when hairy vetch was supplied at 2~3 weeks before rice transplanting compared to that of 1 week. The proper amount of hairy vetch incorporated into soil without nitrogen fertilization was $15{\sim}20ton\;ha^{-1}$. There was a severe lodging of rice with yield reduction when hairy vetch was supplied over $25ton\;ha^{-1}$. When $20ton\;ha^{-1}$ of hairy vetch was supplied the rice yield increased by 6% due to the increase of panicle number per square meter 20%.

• Molecules and Cells
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• v.24 no.1
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• pp.83-94
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• 2007

During monocarpic senescence in higher plants, functional stay-green delays leaf yellowing, maintaining photosynthetic competence, whereas nonfunctional stay-green retains leaf greenness without sustaining photosynthetic activity. Thus, functional stay-green is considered a beneficial trait that can increase grain yield in cereal crops. A stay-green japonica rice 'SNU-SG1' had a good seed-setting rate and grain yield, indicating the presence of a functional stay-green genotype. SNU-SG1 was crossed with two regular cultivars to determine the inheritance mode and identify major QTLs conferring stay-green in SNU-SG1. For QTL analysis, linkage maps with 100 and 116 DNA marker loci were constructed using selective genotyping with $F_2$ and RIL (recombinant inbred line) populations, respectively. Molecular marker-based QTL analyses with both populations revealed that the functional stay-green phenotype of SNU-SG1 is regulated by several major QTLs accounting for a large portion of the genetic variation. Three main-effect QTLs located on chromosomes 7 and 9 were detected in both populations and a number of epistatic-effect QTLs were also found. The amount of variation explained by several digenic interactions was larger than that explained by main-effect QTLs. Two main-effect QTLs on chromosome 9 can be considered the target loci that most influence the functional stay-green in SNU-SG1. The functional stay-green QTLs may help develop low-input high-yielding rice cultivars by QTL-marker-assisted breeding with SNU-SG1.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.57 no.2
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• pp.182-187
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• 2012

Objective of this research was to evaluate the effects of different organic matter on growth and yield in rice plants and suppression of weed occurrence in paddy soil. The treatments consisted of rice bran, expeller cake, or combination of rye green manure and rice bran without any agrochemical or fertilizer. At 50 days after transplanting (DAT), plant height of rice between conventional practice and expeller cake treatments were similar, while rice bran treatment was inhibited growth of rice during growing period. Also, heading date of rice among the all treatments was not significantly different. Rice yield in expeller cake or rye green manure and rice bran treatments was attained to 91% and 98% of the conventional practice, respectively, while the value in rice bran treatments was just 82%. On the other hand, at 40 DAT of rice plants, occurred major weed species in organic matter treatments were four species, while those in conventional practice were two species. Additionally, the dry weight of weeds in rice bran treatment was significantly inhibited compared to it of expeller cake or combination of rye green manure and rice bran treatments, while the value in rice bran treatment was higher than the conventional practice.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.47 no.2
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• pp.137-141
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• 2002

Decomposition of green manure is necessary for the nutrient supply in farm soil. Hairy vetch as a green manure is superior to other winter legumes in terms of wintering ability and N accumulation. This experiment was carried out to investigate the decomposition and N release of hairy vetch and its effect on rice production as the following crop in paddy field. Decomposition of hairy vetch placed by soil depth of 0, 10 and 20cm at transplanting time was investigated by mesh bag method, which was enclosed chopped residue in mesh bags. The fate of $^{15}$ N derived from $^{15}$ N-labeled hairy vetch was investigated at harvest in three levels of N fertilization. Grain yield of the transplanted paddy rice cultured with hairy vetch as starter N were compared with that of applying urea as starter N in the field. Hairy vetch residue decomposed very rapidly both in transplanted and dry-seeded paddy field. In transplanted paddy field, hairy vetch residue lost 72-81 % and 86-90% of its weight after one and five month, respectively, as affected by incorporation depth. The C/N ratio of the decomposing vetch residue increased sharply during the early stages and after then, decreased slowly. The amounts of N and P released from the vetch were about 90% and 97% of initial content after one month, respectively. Recoveries of hairy vetch-$^{15}$ N by rice plant were 30.6, 34.6 and 35.7% in 0, 6 and 12 kg urea-N 10 $a^{-l}$ application, respectively, indicating that N fertilization increased the recovery of hairy vetch. $^{15}$ N. Hairy vetch residue incorporated as starter maintained significant N $H_4$$^{+}$-N concentration in soil water of plow layer until effective tillering stage. Grain yield in the plot applied with hairy vetch was not significantly different from that in the plot with urea. We concluded that hairy vetch incorporation could substitute starter N fertilization and showed possibility to reduce N amount of top-dressing.g.g.