• Journal of the Korean Society of International Agriculture
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• v.30 no.4
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• pp.370-375
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• 2018

In order to promote the mechanized cultivation of perilla for seed, which has been increasing in cultivation area and production recently as demand increases according to the health-functional effects, we carried out this experiment to determine the optimum sowing time of perilla to minimize the seed loss at harvest and increase the yield. We used two different types of perilla varieties, 'Sodam(small-branch)' and 'Deulsaem(multi-branch)', and the sowing time was June 15, June 30, July 15 and August 1. As the sowing time is late, days of growth from sowing to flowering were shortened, and they were shortened from 14, 26 and 31~32 days on June 30, July 15 and August 1 as compared with June 15, respectively. And, the stem length and culm diameter were shortened or tapered and the number of nodes tended to decrease. The number of effective branch was 82%, 61% and 56% on June 30, July 15 and August 1 as compared with June 15, respectively. Accordingly, it seems to make against in securing the yield from July 15. And, the lowest cluster height was generally shorter as the sowing time is late, and the height was below 15cm on July 15 and August 1. It seems that this may work against the machine harvest. There was a high degree of significance between the sowing time and the yield. Although, the total yield was not statistically significant among June 15, June 30 and July 15, the ratio of shattering seed at harvest was in order of July 15, August 1(30.3%)> June 15(15.3%)> June 30(13.5%). Therefore, the net yield except for shattered seed was higher in order of June 30${\geq}$ June 15> July 15> August 1. This tendency was characteristic regardless of variety and sowing method. And, the protein content in perilla seed increased as the sowing time was delayed, and the content was the highest on August 1. The content of crude fat was relatively high on June 15 and July 15 in 'Sodam', and June 30 and July 15 in 'Deulsaem', respectively. And, the content of linolenic acid was found to be the highest on August 1. As a result, the optimal sowing time for machine harvest of perilla for seed is about June 30. At this time, it is determined that the sowing time is the most suitable to be advantageous in increasing the yield of perilla seed, while minimizing the seed loss due to the shattering at harvest.

• Journal of Korean Society of Forest Science
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• v.106 no.4
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• pp.380-387
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• 2017

This study was carried out to determine fertilization effects on allometric equations and biomass production in a Moso bamboo (Phllostachys pubescens) stand of the Gajwa National Experimental Forests, Jinju, Korea. The study site was fertilized for approximately 30 years to produce edible bamboo shoots. Total 20 bamboos (10 fertilized and 10 unfertilized) were cut to develop allometric equations and to estimate biomass accumulation of each bamboo component. Allometric equations of each bamboo component in the fertilized and unfertilized plots were significant (P < 0.05) with diameter at 20 cm from ground ($D_{20}$), diameter at breast height (DBH), culm height (H), and $DBH^2{\cdot}H$. Aboveground biomass estimated by the allometric equations (DBH) was significantly higher in the unfertilized plots ($106.38Mg\;ha^{-1}$) in culm density of $6,833culm\;ha^{-1}$ than in the fertilized ($57.68Mg\;ha^{-1}$) plots in culm density of $4,633culm\;ha^{-1}$. The proportion of each biomass component was culm (79%), followed by branches (14%) and leaf (7%) in the fertilized plots, whereas it was culm (81%), followed by branches (13%), and leaf (6%) in the unfertilized plots. The results indicate that aboveground biomass accumulation in a Phllostachys pubescens stand was little affected by fertilizer application because of the difference of culm density.

• Journal of Aquaculture
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• v.9 no.1
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• pp.25-42
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• 1996

The study has been conducted to know an appropriate feeding strategy and effects of the rearing density on larval growth of the rockfish, Sebastes schlegeli. The results obtained are as fellowed ; 1. Thirty-day-old larvae reached at $25.25{\pm}3.76$ mm in total length and $0.23{\pm}0.07$ g in body weight in experiment A, at which rotifer was provided from the beginning to the end of 30-day experiment, Anemia from 3th to 18th day, and artificial feed from 13th to 30th day after hatching. When rotifer was provided for 30 days, Artemia from 6th to 18th day, and artificial feed from 18th to 30th day after hatching (experiment B), these larvae grew up to $27.52{\pm}2.50$ mm in total length and $0.26{\pm}0.06$ g in body weight. On the other hand, when rotifer and artificial feed were supplied with the same time schedule as shown in experiment B, and Artemia was feed from 6th to 30th day after hatching (experiment C), the total length and body weight of those larvae were $23.22{\pm}3.44$ mm and $0.15{\pm}0.05$ g, respectively. The best result for larval growth was obtained from experiment B. The survival rates estimated were $57.6\%$ in experiment A, $66.4\%$ in experiment B, and $44.4\%$ in experiment C. 2. The growth in total length of the larvae according to their rearing days could be represented by the following equations : Experiment A : Y=4.350+0.116X+$1.887X^2$ (r=0.993) Experiment B : Y=4.500+8.931X+$2.221X^2$ (r=0.994) Experiment C : Y=4.478+5.734X+$1.881X^2$(r=0.990) The average number of Artemia nauplius intaken by the larvae was rapidly increased between 15th and 20th day afer hatching, and 9, 212, 242, 750, and 1,171 nauplius were found in the different sizes of larvae, whose total length were 5.65, 6.81, 9.45, 14.96, and 24.52 mm, respectively. 3. Larval growth in total length and body weight reared at four different densites (A: 1.8 $kg/m^3$, B; 4.0 $kg/m^3$, C; 5.0 $kg/m^3$, D; 6.2 $kg/m^3$) indicated that the best growth was found in experiment A, at which the larval were reared at the lower density and the final survival rates extimated were $92.9\%$ in exp. A, $99.5\%$ in exp. C, $89.0\%$ in exp. B, and $88.2\%$ in exp. D. The amount of production per cubic meter turned out to be 30.45 kg in exp. D, 25.89 kg in exp. C, 20.75 kg in exp. B and 10.48 kg in exp. A. therefore, considering both larval growth and survival rate, higher yields seemed to be attainable at the relatively high-rearing density.

• Horticultural Science & Technology
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• v.33 no.4
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• pp.591-597
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• 2015

We determined the total C and N stocks in trees and soils after 1 year of fertilization in an experimental orchard with 16-year-old 'Niitaka' pear (Pyrus pyrifolia Nakai cv. Niitaka) trees planted at $5.0m{\times}3.0m$ spacing on a Tatura trellis system. Pear trees were fertilized at the rate of 200 kg N, 130 kg P and $180kg\;K\;ha^{-1}$. At the sampling time (August 2013), trees were uprooted, separated into six fractions [trunk, main branches, lateral branches (including shoots), leaves, fruit, and roots] and analyzed for their total C and N concentrations and dry masses. Soil samples were collected from 0 to 0.6 m in 0.1 m intervals at 0.5 m from the trunk, air-dried, passed through a 2-mm sieve, and analyzed for total C and N concentrations. Undisturbed soil core samples were also taken to determine the bulk density. Dry mass per tree was 5.6 kg for trunk, 12.0 kg f or m ain branches, 15.7 kg for lateral branches, 5.7 kg for leaves, 9.8 kg for fruits, and 10.5 kg for roots. Total amounts of C and N per tree were respectively 2.6 and 0.02 kg for trunk, 5.5 and 0.04 kg for main branches, 7.2 and 0.07 kg for lateral branches, 2.6 and 0.11 kg for leaves, 4.0 and 0.03 kg for fruit, and 4.8 and 0.05 kg for roots. Carbon and N stocks stored in the soil per hectare were 155.7 and 14.0 Mg, respectively, while those contained in pear trees were 17.8 and $0.2Mg{\cdot}ha^{-1}$ based on a tree density of 667 trees/ha. Overall, C and N stocks per hectare stored in the pear orchard were 173.6 and 14.2 Mg, respectively. Compared with results obtained in 2012, the amounts of C stocks have increased by $17.7Mg{\cdot}ha^{-1}$, while those of N stocks remained virtually unchanged ($0.66Mg{\cdot}ha^{-1}$).

• Journal of The Korean Society of Grassland and Forage Science
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• v.30 no.2
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• pp.127-134
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• 2010

A study was conducted to determine the effects the of cattle manure application on forage yield, quality and soil in orchard grass pasture at the experimental field of Subtropical Animal Experiment Station, National Institute of Animal Science from 2008 to 2009. The experiment was arranged in a randomized complete block design with three replications. The treatment consisted of chemical fertilizer (CF N-200 kg/ha), cattle manure 50% (basis N, CM50%), CM100% (basis N), CM200% (basis N). The dry matter (DM) yield of CM200% was the highest among the other treatments. CF showed the highest average crude protein (CP) content by 12.4% and CM50% showed the lowest content by 11.0%. Average acid detergent fiber (ADF) and neutral detergent fiber (NDF) content were 30.4 and 69.7% respectively. All treatments have narrow range of total digestibility nutrient (TDN) from 64.0% to 69.1%. But there were big difference between treatment in forage nitrate content. Changes of physical and chemical properties of soils for applications of CF 200% and CM 200% was clearly in cattle manure application. Especially, CM application in pasture increased CF application with respect to soil pH, organic matter (OM), and avaliable phosphorous ($P_2O_5$) contents of soils.

• Horticultural Science & Technology
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• v.31 no.6
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• pp.828-832
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• 2013

To report country-specific carbon and nitrogen stocks data in a pear orchard by Tier 3 approach of 2006 IPCC guidelines for national greenhouse gas inventories, an experimental pear orchard field of the Pear Research Station, National Institute of Horticultural & Herbal Science, Rural Development Administration, Naju, Korea ($35^{\circ}01^{\prime}27.70N$, $126^{\circ}44^{\prime}53.50^{\prime\prime}E$, 6 m altitude), where 15-year-old 'Niitaka' pear (Pyrus pyrifolia Nakai cv. Niitaka) trees were planted at a $5.0m{\times}3.0m$ spacing on a Tatura trellis system, was chosen to assess the total amount of carbon and nitrogen stocks stored in the trees and orchard soil profiles. At the sampling time (August 2012), three trees were uprooted, and separated into six fractions: trunk, main branches, lateral branches (including shoots), leaves, fruits, and roots. Soil samples were collected from 0 to 0.6 m depth at 0.1 m intervals at 0.5 m from the trunk. Dry mass per tree was 4.7 kg for trunk, 13.3 kg for main branches, 13.9 kg for lateral branches, 3.7 kg for leaves, 6.7 kg for fruits, and 14.1 kg for roots. Amounts of C and N per tree were respectively 2.3 and 0.02 kg for trunk, 6.4 and 0.07 kg for main branches, 6.4 and 0.09 kg for lateral branches, 6.5 and 0.07 kg for roots, 1.7 and 0.07 kg for leaves, and 3.2 and 0.03 kg for fruits. Carbon and nitrogen stocks stored between the soil surface and a depth of 60 cm were 138.29 and $13.31Mg{\cdot}ha^{-1}$, respectively, while those contained in pear trees were 17.66 and $0.23Mg{\cdot}ha^{-1}$ based on a tree density of 667 $trees{\cdot}ha^{-1}$. Overall, carbon and nitrogen stocks per hectare stored in a pear orchard were 155.95 and 13.54 Mg, respectively.

• Journal of Ecology and Environment
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• v.29 no.6
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• pp.585-591
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• 2006

We measured the litterfall quantity and investigated the nutrient dynamics in decomposing litter for three years at the LTER sites installed in a deciduous broadleaf natural forest in Mt. Gyebangsan, South Korea. Litterfall production was significantly different among the sampling dates, whereas it was not significantly different among the years. The total annual mean litterfall production for three years was 6,593 kg $ha^{-1}$ $yr^{-1}$ and leaf litter accounted for 82.6% of the litterfall. The leaf litter quantity was highest in Quercus mongolia, followed by leaf of other species, Betula schmidtii, Kaplopanax pictus, Acer pseudo-sieboldianum, etc., which are dominant tree species in the site. The mass loss from the decomposition of leaf litter was fastest in Cortinus controversa (100%), followed by A. preudo-sieboldianum, K. pictus, and B. schmidtii. 100% of litter for C. controversa, 96.1% for A. pseudo-sieboldianum, 92.8% for K. pictus decomposed, while 66.2% of litter for Q. mongolia decayed for 1,003 days. The lower rate of the mass loss in the litter of Q. mongolia may be attributed to the difference in substrate quality, such as lower nutrient concentrations compared with those of other tree species. The concentrations of N, P, and Ca for five litter types increased over time, while the concentrations of K and Mg decreased over time. Compared with the nutrients in the litter of Q. mongolia, the nutrients (N, P, K, Ca, Mg) in the litter of other species, C. controversa, A. pseudo-sieboldianum, and K. pictus, were released more rapidly. The results showed that the mass loss and the nutrient dynamics in the litter are variable depending on the tree species even in the same site conditions.

• Journal of Mushroom
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• v.19 no.3
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• pp.166-175
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• 2021

In this study, monokaryons of "Heukari" (Pleurotus ostreatus) and "Hosan" (Pleurotus pulmonarius) were separated to remove the cell wall, and a cross-species protoplast fusion was developed through chemical treatment with polyethylene glycol. The protoplast-fused PF160306 and PF160313 strains have a culture period of 10 and 2 days shorter than that of the "Heuktari" and "Hosan" cultivars, respectively. Furthermore, the growth of the strains was faster than that of the existing cultivars. The yield was 135.9 g per bottle, which was approximately 8% higher than that of the commercially available "Hosan" cultivar; however, it was not statistically significant. A growth survey was conducted after treatment at five temperatures (15, 18, 21, 23, and 25℃). The growth of the strains accelerated with the increase in temperature. However, at 21℃, the yellow color of pileus was the brightest. Band pattern, assessed using URP Primer 7, was similar to that of the "Hosan" cultivar. The DPPH radical scavenging capacity and polyphenol content were 62.5% and 43.5 mg/mL, respectively, for "Sunjung" and 65.7% and 49.9 mg/mL, respectively, for PF160313. Furthermore, the antihypertensive activities of the "Sunjung" cultivar and PF160313 were similarly high at 74% and 75%, respectively. In conclusion, cross-species hybridization via the protoplast fusion technique can be used for obtaining primary data for mushroom breeding to develop new varieties. In addition, the protoplast fusion technique might aid in expanding the market for yellow mushrooms.

• Journal of Bio-Environment Control
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• v.25 no.1
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• pp.63-70
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• 2016

Water drainage from the open hydroponics often causes significant environmental pollution due to agrochemicals and loss of water and nutrients. The objectives of this study were to show the potential application of an irrigation schedule based on threshold values of volumetric substrate water content for tomato (Solanum lycopersicum L. 'Samsamgu') cultivation in a commercial hydroponic farm during spring to summer cultivation. This study was performed for minimizing effluent from coir substrate hydroponics using a frequency domain reflectometry (FDR) sensor-automated irrigation, as compared with an integrated solar-radiation (IR) and conventional timer-irrigation (TIMER) after transplanting. In results, no significant difference in daily irrigation volume was found among the treatments until 88 days after transplant (DAT). However, during the 88 to 107 DAT, the daily irrigation volume was in the order of IR (2125 mL) > TIMER (2063 mL) > FDR (1983 mL), and during the 108 to 120 DAT, it was in the order of IR (2000 mL) > TIMER (1664 mL) > FDR (1500 mL). The lowest drainage volume was observed in the FDR treatment with the order of IR (12~19%) > TIMER (4~12%) > FDR (0~7%) during the entire growing period. A lower irrigation volume in the FDR treatment after 88 DAT may be due to the sensor's detecting capacity for less water absorption by plant after completing fruit maturity with apical pruning and removal of lower leaves, while a higher irrigation volume in the IR treatment may be due to gradual increase in integrated solar-radiation amount as closer to summer season. There was no significant difference in plant growth and fruit yield among the treatments; however, a 11% and 18% of higher soluble sugar content was observed in the FDR than that of TIMER and IR treatment. respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.18
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• pp.1-27
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• 1975

Experiment I: A field experiment was conducted in an attempt to find the effect of top-dressing at heading time in different levels of nitrogen application and of different positioned leaf blades formed by the treatment of leaf defoliation at heading time on the ripening and the yield of rice. The results obtained are as follows: 1. Average number of ears per hill and average number of grains per ear in different levels of nitrogen application were increased as the amount of nitrogen applied was increased. while the rate of ripened grains the yield of rough rice and the weight of 1, 000 kernels of brown rice were decreased respectively as the amount of nitrogen applied was increased. 2. The rate of ripened grains and the weight of 1.000 kernels of brown rice in different levels of nitrogen, top-dressing at heading time were larger than those in control and increased. The yield of rough rice although statistically significant differences were not recognized, were numerically increased. 3. The rate of ripened grains, the yield of rough rice, the weight of 1, 000 kernels of brown rice and the rate of hulling in different treatments of leaf defoliation were remarkably decreased as the degree of leaf-defoliation became larger. 4. The rate of ripened grains, the yield of rough rice, the weight of 1, 000 kernels of brown rice and the rate of hulling in different combinations of number of remained leaves positioned differently, formed the order of $L_1(flag leaf)>L_2>L_3>L_4$ when only one leaf blade was remained, and were increased as the positions of leaves were higher when two leaf blades. were, remained. 5. In case of decrease in the number of leaf blades positioned differently, by the treatment of leaf. defoliation, rate of ripened grains, the yield of rough rice, the weight of 1, 000 kernels of brown rice and the rate of hulling were increased as the area of remained leaves became larger and the nitrogen content of a leaf blade was increased. 6. There was a tendency that the increase in the amount of fertilizer application made the rate of ripened grains and the weight of 1, 000 kernels of brown rice reduced in any number of remained leaf blades, but the application of top-dressing at heading. time resulted in the reverse tendency. The yield of rough rice showed a tendency to be increased as the amount of basal dressing and top-dressing increased and for the application of top-dressing at heading time, the yield of rough rice was less at the smaller number of those. 7. The productivity effect of the rate of ripened grains and the yield of brown rice covered by leaf blades was more than 50 per cent and that of the. weight of 1, 000 kernels of brown rice was not more than 1.0 percent. As the amount of nitrogen application increased the. effect of leaf blades on the rate of ripened. grains and the weight of 1, 000 kernels of brown rice was increased. The effect of leaf blades on the weight of brown rice was increased as the amount of basal dressing-application, but the effect was decreased as the amount of top-dressing at heading time increased, 8. The productivity effects of different positioned leaf blades on the rate of ripened grains, the yield of rough rice and the weight of 1, 000 kernels of brown rice were in order of $L_1(flag leaf)>L_2>L_3>L_4$ the productivity effects of $L_1$ and $L_2$ had a tendency to be increased as the amount of nitrogen applied was increased. Experiment II: A field experiment was done in order to disclose the effect of the time of nitrogen application on yield component and the effect of different positioned leaves formed by leaf defoliation at heading time on the rate of ripened grains and the yield of rice. The results obtained are as follows: 1. Average number of ears per hill was increased in the treatment of nitrogen application from basal dressing to 22 days before heading and in the treatment of application distributed weekly. Number of grains was increased in the treatment of nitrogen application from 36 days to 15 days before heading. The rate of ripened grains was, lower in the treatment of nitrogen application from top-dressing to 15 days before heading than in that of non-application, was higher in the treatment of nitrogen application within 8 days before heading, and was the lowest in that of application 29 days before heading. The yield of rough rice was the highest in the treatment of nitrogen application from 29 days to 22 days before heading. The weight of 1, 000 kernels of brown rice was a little high in the treatment of application from 29 days to 8 days before heading. 2. The rate of ripened grains the yield of rough rice, the weight of 1, 000 kernels of brown rice and the rate of hulling in different treatments of leaf defoliation were remarkably decreased as the degree of leaf defoliation got larger and there were highly significant differences among treatments. There was also a recognized interaction between the time of nitrogen application and leaf defoliation. 3. In relation to the rate of ripened grains, the weight of 1. 000 kernels of brown rice and the rate of hulling in different numbers of remained leaves positioned differently and their combinations, the yield components were in order of $L_1(flag leaf)>L_2>L_3>L_4$ when only one leaf was remained, which indicated that the components were increased as the leaf position got higher. When two laves were remained, the rate of ripened grains, the yield of rough rice and rate of hulling were high in case of the combinations of upper positioned leaves, and the increase in the weight of 1, 000 kernels of brown rice appeared to be affected most]y by flag leaf. When three leaf blades were remained similarly the components were increased with the combination of upper positioned leaf blades. 4. In case of decreased different positioned leaf blades by treatment of leaf defoliation, there was a significant positive regression between the leaf area, the dry matter weight of leaf blades and the nitrogen contents of leaf blades, and rate of ripened grains and the yield of rough rice, but there was no constant tendency between the former components and the weight of 1. 000 kernels of brown rice. 5. The closer the time of fertilizer application to heading time, the more the rate of ripened grains and the weight of 1, 000 kernels was decreased by defoliation, and the less were the remained leaf blades, the more remarkable was the tendency. The rate of ripened grains and the weight of 1. 000 kernels was increased by the top-dressing after heading time as the number of remained leaf blades. When the number of remained leaf blades was small the yield of rough rice was increased as the time of fertilizer application was closer to heading time. 6. Discussing the productivity effects of different organs in different times of nitrogen application, the productivity effect of a leaf blade on the rate of ripened grains was higher as the time of nitrogen application got later, and in the treatment of non-fertilization the productivity effect of a leaf blade and that of culm were the same. In the productivity effect on the yield of brown rice, the effect of culm covered more than 50 percent independently on the time of nitrogen application, and the tendency was larger in the treatment of non-fertilizer. The productivity effect of culm on the weight of 1. 000 kernels of brown rice was more than 90 percent, and the productivity effect of a leaf blade was increased as the time of application got later. 7. The productivity effect of a leaf blade in different positions on the rate of ripened grains, the yield of rough rice and the weight of 1, 000 kernels of brown rice had a tendency to be increased as the time of application got later and as the position of leaf blades got higher. In the treatment of weekly application through the entire growing period, the rate of ripened grains and the yield of rough rice were affected by flag leaf and the second leaf at the same level, the but the weight of 1, 000 kernels of brown rice was affected by flag leaf with more than 60 percent of the yield of total leaves.