• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.5
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• pp.420-424
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• 2006

This experiment was conducted to elucidate the basic physiological phenomena of pollination and fertilization for breeding in perilla (Perilla frutescens) through different 6 varieties derived from 2 genera under 4 temperature conditions at day and night. The pollen germination was observed after 30 minutes and pollen tube reached the lower part of pistil after 1 hour from artificial pollination. Seed formation was affected by temperature condition and a variety. The early maturing variety 'YCPL 25' showed a poor seed formation rate under the night temperature below $15^{\circ}C$, but the late maturing variety 'YCPL263' did not lowered even though the night time temperature was $10^{\circ}C$. The function of pistil was long maintained under the low temperature from the fact that if the live pollen pollinate artificially to the flower that does not form seed under low temperature, fruiting was made. Pollen was created and pollen tube was developed in the time of petal becomes bigger than calyx in five varieties, 'YCPLl77-1' etc. However, pollen was made and pollen tube was made only 71% in a green chajogi 'YCPL205-1'. These physiological phenomena of pollination and fertilization could be applicable to the emasculation and an effective breeding in perilla.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.34 no.4
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• pp.440-448
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• 1989

The present experiment was conducted to investigate the effects of seeding date on agronomic characters including seed weight of soybean (Glycine max (L.) Merr.) at Sunchon, the southern coastal area of Korea. One hundred eighteen native and improved varieties were used in this study. As the seeding date was delayed, the number of days to flowering for the cultivars was reduced. This trend was more obvious in late maturing cultivars(LMC) than in early and medium maturing cultivars (EMC and MMC). Late seeding also resulted in decrease in the number of leaves, stem length, and number of nodes. The heaviest seed weight was obtained with EMC and MMC planted on May, and seed weight decreased with delayed seeding date. Seed weight was positively correlated with number of days to flowering, number of total leaves at flowering, stem length and number of nodes on main stem at maturity. Based on seed weight the cultivars was classified into five types: Type I; Seed weight of the cultivars decreases with delayed seeding date. Type II; Seed weight of the cultivars does not vary with seeding date. Tyep III; Seed weight of the cultivars increases with delayed seeding date. Type IV; Seed weight of the cultivars increases when the seeding date approached the appropriate seeding date, but decreases thereafter. Type V; The reversed type IV. Type I, II, III, IV and V occupied 37, 16, 17, 10 and 20％ of the tested cultivars, respectively.

• Journal of The Korean Society of Grassland and Forage Science
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• v.28 no.3
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• pp.177-184
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• 2008

This experiment was carried out to breed a cold-tolerant variety of Italian ryegrass (Lolium multiflorum Lam.) in Grassland and Forage Crops Division, National Institute of Animal Science, RDA, Suwon from 1999 to 2006. ew variety, Kowinmaster as a diploid variety was light-green in leaf color and had medium and semi-erect growth habit in late autumn and early spring, respectively. Kowinmaster was 13th May in heading date as a medium-maturing variety. Especially, Kowinmaster was similar to Florida 80 in flag leaf width, longer 3cm in flag leaf length and longer 6cm in plant length than those of control variety, Florida 80, respectively. Stem width of Kowinmaster was similar to that of Florida 80. Cold tolerance of Kowinmaster was better than that of Florida 80. Dry matter yield (9,521 kg/ha) of Kowinmaster was 2% more than that of Florida 80. Feed value of Kowinmaster was 12.1% in crude protein, 70.9% in In vitro dry matter digestibility and 32.9% in acid detergent fiber that were similar to those of Florida 80, respectively, but in neutral detergent fiber, Kowimaster was 56.0% that was 1% lower than that of Florida 80.

• Research in Plant Disease
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• v.9 no.4
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• pp.183-188
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• 2003

Correlation between the rice panicle blast and the rice quality and yield was evaluated in field experiments. Results showed that there were high positive correlations between the disease incidence and the rice yield and quality. The correlation coefficients between the disease incidence and the yield of Jinmibyeo, an early maturing cultivar and Juanbyeo, an middle maturing cultivar were $R^2$=0.6518 and $R^2$=0.7977, respectively. As the disease incidence increased weight of 1,000 grains of the two cultivars decreased showing coefficients $R^2$=0.6848 and $R^2$=0.7841, respectively. Percentage of matured grains in healthy plots were 95 and 98%, however, as the disease incidence increased percentage of matured rice grains decreased showing $R^2$=0.4745 in Jinmibyeo and $R^2$=0.703 in Juanbyeo. As the disease increased, rate of the damaged rice also increased, showing $R^2$=0.6607 in Jinmibyeo and $R^2$=0.6706 in Juanbyeo, respectively.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.4
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• pp.279-283
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• 2004

This experiment was carried out at paddy field (commercial silty loam soil) in the southwestern Korea. Pungsannamulkong, a determinate growth habit, was a relatively high yielding and late maturing cultivar, and Han­namkong, a semi determinate growth habit, was a relatively low yielding and early maturing cultivar. Seeds were sowed at two plants and with a planting density of $70{\times}10cm$ on May 26, 2003. Fertilizer was applied prior to planting at a rate of 3.0-3.0-3.4g $(N-P_2O_5-K_2O)\;per\;m^2$ by all basal fertilizations. Experimental design was a randomized complete block with three replications. Seed yield was higher in Pungsannamulkong by 362g per $m^2$ than in Hannamkong of 260g per $m^2$ Also, the number of pod, number of seed, and number of seed per pod were greater in Pungsannamulkong than in Hannamkong. The number of leaves per $m^2$ showed similar with two soybean cultivars up to August 24 but thereafter it decreased in Hannamkong. The leaf area up to August 4 increased in Hannamkong higher than in Pungsannamulkong, but after that time, Pungsannamulkong had greater leaf area than Hannamkong. The shoot and leaf dry matter of two soybean cultivars from June 23 to August 4 were similar but thereafter, Pungsannamulkong had a significantly greater than Hannamkong. Crop growth rate (CGR), relative growth rate (RGR) and net assimilate rate (NAR) for Punsannamulkong were relatively higher than Hannamkong but leaf area ratio (LAR) and specific leaf weight (SLW) showed higher in Hannamkong. Most of leaves distributed in the ranges of 80-90cm and 60-70cm from the soil surface in Punsannamulkong and Hannamkong, respectively. Pods of Punsannamulkong ranged 10-80cm from the soil surface and most of pods were distributed at 40-50cm. Photosynthetic rate at the flowering stage showed a significant difference between cultivars in the upper most leaf position. There was no significant difference of the photosynthetic rate at $7^{tn}$ leaf at the flowering stage, and the uppermost and 7th leaf position at the seed development stage between two soybean cultivars.

• Korean Journal of Soil Science and Fertilizer
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• v.30 no.2
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• pp.184-188
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• 1997

To investigate the absorption and transfer factor(TF) of Sr-85 by rice(Oryza sativa L.), experiments were carried out through pot cultivations on a sandy-loam soil treated 74 and 222Bq per gram of soil in a plastic film house. Sr-85 absorption rates of Ilpoombyeo, late maturing variety and Odaebyeo, early maturing variety, at harvesting stage, were 0.39-0.43% and 0.66-0.73%, respectively. Sr-85 absorption rates of Odaebyeo were about 1.5 times higher than those of Ilpoombyeo. Ratios of Sr-85 radiation and Sr-85 concentration in brown rice were much lower compared with those in straw and husk. Sr-85 concentrations in each part of Odaebyeo were remarkably higher than those of Ilpoombyeo. Transfer factor of Sr-85 from soil to plant ranged from 0.037 of brown rice to 4.13 of rice straw at harvesting stage. The order of the Sr-85 transfer factor in plant parts was straw>husk>brown rice. Sr-85 concentrations treated in soil had no effect on the growth and yield of rice.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.4
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• pp.447-454
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• 1987

Five soybean varieties of two early maturing; Karikei 73 and SS79168, and three late maturing; Tohoku 76, Baegunkong and Jangbaegkong, were used and evaluated in the study, Of the varieties examined, Karikei 73 was characterized by the delayed leaf senescence, To investigate the periodical trends of sugars in plant organs and their roles to the nitrogen fixing activity of root nodules, the concentrations of reducing and non-reducing sugar in root and nodules during the grain filling period were measured. The concentration of non-reducing sugar in roots was not changed up to the stage of R6 for all of the varieties but it decreased rapidly thereafter for the varieties except Karikei 73. No such rapid decrease in the concentration of non-reducing sugar in the roots was observed for Karikei 73 having the characteristics of delayed leaf senescence. The concentration of reducing sugar in the root nodules was not greatly changed for all of the varieties up to the stage of R6 regardless of the earliness of varieties but increased temporarily at R6.5 when there was a rapid decrease in ARA. The phenomenon explained the fact that nitrogen fixing activities were controlled not only by supplying sugars as the source of energy for nitrogen fixation, but also by the need for fixed nitrogen of the plant. The concentration of non-reducing sugar in root nodules also increased up to the stage of R6-R6.5 but decreased at R7, which could apply the same explanation as in the concentration of reducing sugar of the root nodules.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.53 no.3
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• pp.273-278
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• 2008

This study set out to investigate the changes to the growth, yield, and flavonoid contents of mungbean according to different seeding times from mid May to mid July in the southern region of Korea. Days to first flowering, days to first maturing, and cultivation period were shorter at later seeding time than earlier seeding time. But later the seeding time was, days from first maturing to first harvesting, days required between harvesting increased. Number of pods at first harvesting and yield of mungbean were highest when seeded at late June, showing increase in yield 14% more than at early June as standard seeding time. However number of seeds per pod and 1,000-seed weight at first harvesting were highest when seeded at mid July. The number of harvesting was smallest at two times when seeded at June or mid July. The contents of average vitexin and isovitexin in mungbean were highest in the order of mid July, late June, and mid May. In particular, their contents reached its highest point in the seeds of the second harvest. Considering the results of the cultivation period, yield, harvesting times, vitexin and isovitexin contents, the proper seeding time of mungbeans in the southern region of Korea will be from late June to mid July.

• Journal of The Korean Society of Grassland and Forage Science
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• v.16 no.4
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• pp.327-337
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• 1996

A field experiment was conducted at SNU Experimental Livestock Farm, Suweon in 1995 to determine effect of planting date on forage performance of wm hybrids of four different maturity groups. A split-plot design replicated three times was used, with com hybrids representing four maturity groups (115, 118, 121 and 125 days) being the main plots and planting dates (3124, 415, 415, 425, 515 and 5/15) the sub-plots. 1. Days to emergence and percent emergence from the March 24 planting were, on the average, 36 days and 58%, respectively, but those from the April 5 to May 15 planting averaged 12 days and 92%, respectively. 2. Plant and ear heights increased gradually as the dates of planting were delayed except the May 15 planting, however, percent ear was decreased as the dates of planting were delayed. There was a trend for the mean lodging percentage of the hybrids to be higher as the planting date was delayed. 3. The 115-and 118-day mediumearly maturing hybrids harvested on August 18 produced silages with a dry matter content between 27 and 30% at all planting dates except the May 15 planting, while the 121-and 125-day medium-late maturing hybrids produced silages with a dry matter wntent less than 27% regardless of any planting dates. 4. There were no significant differences in mean dry matter yield among the hybrids, but significant mean TDN yield differences were found. The 115-, 118- and 125-day hybrids had significantly higher mean TDN yield than the 121-day hybrid. There were significant differences in mean dry matter and TDN yields among the planting dates. The mean dry matter and TDN yields from the April 5, 15 and 25 plantings were significantly higher than those of other plantings, however, there were no significant differences in mean TDN yield among the April 5, April 15 and April 25 plantings. No significant planting date $\times$ maturity interactions were found for both the dry matter and TDN yields. 5. Mean stover NDF and ADF contents of the 115- and 118day hybrids were higher than those of the 121- and 125-day hybrids, but the reverse was true for mean stover IVDMD and RFV. Mean stover NDF an ADF contents increased with earlier plantings, but mean stover IVDMD and RFV increased when planting was delayed. Results of this experiment indicate that for corn planting in central and northern areas of Korea, early to mid-April may be the right time with the 115-to 118-day maturity hybrids when silage making before August 20 is taken into consideration.

• The Journal of Natural Sciences
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• v.8 no.2
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• pp.159-168
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• 1996

The major morphological characteristics of 97 lines selected from 1,510 local collection lines of Paeonia spp. were studied and classified into some groups according to their Q correlation. The Coefficient of Variation of 8 characteristics in 97 lines varied greatly with the range from 21.3% to 127.1%. The 22 lines with useful morphological characteristics selected from 97 lines had 2n=10 chromosomes, in which there were no difference among the number of chromosomes of 22 lines. The 97 lines were classified into 14 groups based upon the results of Q correlation analysis obtained from data with 16 quantitative factors; Group III and group VI were divided into two sub-groups. Group I was large flowered lines with a single flower, Group IIIa, doubled flowered lines, Group VII, late maturing lines and Group IX, early maturing lines flowering in 17th May. Group VIII were dwarf type lines which has the shortest stem length and leaf length among 14 groups, which are suitable for potted plants. Group XIII had a lot of stems per plant and a large type leaf with leaf length and width. A needle-type leaf was found in Group X, whereas a wide and oval-type leaf in group XII.