• KOREAN JOURNAL OF CROP SCIENCE
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• v.40 no.6
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• pp.705-710
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• 1995

In order to find out the effect of rainfall at harvesting season on germination of malting barley, the seeds sampled from Cheju island and southern part of Korea were examined. The germination rate of seeds from Cheju island where rainfall was frequent at harvesting season, ranged from 46 to 71%, even though disease infection of the seeds was not that serious as would be expected. High sugar content of seed was resulted from the degradation of carbohydrates during the harvest season. From TZ test the rainfall - affected seeds were found to be highly viable but in the state of secondary dormancy. Results of cold germination test showed that the seeds were recovered from the secondary dormancy. Therefore, it was recommended that the seeds affected by the rainfall at harvesting season should be utilized after 12 months when the dormancy period terminated. The germination percent of the seeds was significantly enhanced by prechilling and / or 1 ppm gibberellic acid treatment. Different seed lots showed different rate of germination and the degree of dormancy.

• Asian Journal of Turfgrass Science
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• v.15 no.1
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• pp.15-20
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• 2001

Two types of annual bluegrass have been reported, and those consist of annual type (Poa annua ssp. annua) and perennial type (Poa annua ssp. reptans). As a weed, annual bluegrasses are commonly found in putting greens and fairways in many golf courses. Due to its strong competitiveness such as tremendous seed reproduction rate a year, prostrate growth habit, and no herbicide availability, annual bluegrasses have been considered as one of the most hard-to-control weeds in turf management systems. A growth chamber study was conducted to determine seed dormancy and to understand seed germination characteristics of annual bluegrass (Poa annua ssp. annua). Freshly harvested seeds showed 80 and 55% germination at 30 and $35^{\circ}C$, respectively, indicating that the optimum temperature of annual bluegrass is $30^{\circ}C$. However, the seed germination occurred only under light condition at any given temperature. This result demonstrated that light is prerequisite for the seed germination, and no primary dormancy of annual bluegrass seed exists. Secondary seed dormancy induced by unfavorable temperatures and dark condition was broken through 4 to 6 wk-storage at $4^{\circ}C$ with moisture, and the stored seeds germinated at $20^{\circ}C$ even under the dark. In red and far-red light trial, fresh seeds resulted in 40% germination under red while no seed germination occurred under far-red light condition, indicating that phytochrome Pr and Pfr could be related to annual bluegrass seed germination. When the far-red light replaced the red the germination was recovered, but this reversibility did not reach to the germination level under the red light only. This result implied that other lights than red and far-red would play an important role on seed germination of annual bluegrass.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.10
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• pp.85-90
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• 1971

Dormancy breaking methods were studied on Avenasterilis seeds. The treatments were: application of alcohol, hot water, low temperature, pure oxygen, thiourea and gibberellic acid. Thiourea treatment with 3 different concentrations (0.25 x 10$^{-2}$ M, 0.625 x 10$^{-2}$ M, 1.25 x 10$^{-2}$ M) had little effect in breaking dormancy. Gibberellic acid treatment applied at 5ppm, 50ppm, 500ppm were effective and maximum germination was obtained with 500ppm. Low temperature treatment at 3$^{\circ}C$ for a week in a refrigerator was also very effective in breaking dormancy. Other treatments were not effective. In all cases, primary seeds germinated significantly better than secondary seeds. Different A. sterilis strains varied significantly in their response to gibberellic acid treatment. Different concentrations of gibberellic acid also gave significantly different responses in breaking dormancy.

• Korean Journal of Weed Science
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• v.16 no.3
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• pp.200-209
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• 1996

It is assumed to be an efficient method for keeping a germinability of weed seeds as long as possible, if a secondary dormancy is not induced by transferring the seeds of which dormancy was broken in wetting condition into drying condition. To investigate its validity, two experiments were carried out on seeds of 9 weed species ; to find out the most effective storage condition in breaking the dormancy of each weed species and to know whether there is a decrease in the germinability by transferring into drying storage condition. The dormancy of Chenopodium album and Stellaria aquatica was released well under the drying condition, but that of Echinochloa crus-galli var. oryzicola by soaking in water. Other weed species were released from dormancy by storage in wetting condition. When the seeds stored in the wetting or soaking condition, are air-dried and then restored at room or low temperature, a decreasing tendency of germinability which might cause a trouble in using them practically, was not observed except on the seeds of Persicaria vulgaris. In the case of Persicaria vulgaris, the low germination since 3 month-storage seemed not to be caused by drying, because a decrease of its germinability was observed with increasing storage period in all of the storage conditions. In contrast, high germination was induced as the seeds of Echinochloa crusgalli var. oryzicola, which were not germinated during the storage in low temperature and wetting condition, were transferred into the room temperature and drying condition. These results suggest that this approach can be one of the efficient methods for keeping a good germinability as long as possible in most weed seeds.

• The Korean Journal of Ecology
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• v.6 no.3
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• pp.187-197
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• 1983

This report is a series of the investigation of the secondary vegetation and succession at the forest fire area in Dangji-Dong of Kyungsang-pookdo province. The forest fires occurred on April 8, 1982. This investigation was carried out from June 18, 1982 to May 29, 1983 once in each season. Before to fires, the Pinus densiflora was dominant and the woody plants of understory were mainly composed of the Quercus serrata, Q. dentata, Lespedeza maritima and L. macimowiczii. Compared with the florstic composition between the unburned and burned areas after the fires, the floristic composition of unburned area comprises: 79 families, 194 genera, 223 species, 26 varieties and 6 formae (255 kinds of vascular plants). The index of similary shows 0.77 (S$\Phi$renson:1948) in this area. The analyses of the life-form compositions in the unburned and burned area show 32.9% and 29.3% in dormancy form (H), 42.4% and 37.7% in disseminule form($D_1$), 80.8% and 82.2% in radicoid form ($R_5$), and 57.7% and 61.8% in erect form(e) respectively. The biological type shows H-$D_1$-R5-e, which is common in both areas, and erect form is generally prevailing in these communities.

• Current Research on Agriculture and Life Sciences
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• v.7
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• pp.41-46
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• 1989

The seeds of Malus sieboldii were collected in late fall of 1988 and stored in cold stratification condition for 15 weeks. Growth regulators such as $GA_3$, BA and ABA were treated to the seed to know germination capacity and seedling growth. The results were as follows. 1) Higher germination was achieved in $GA_3$ and BA plots, But ABA treatment showed lower germination percentage and physiological dwarf and also induced to the secondary dormancy condition in partly. 2) Average length of time for germination was delayed over 2 days in ABA plot when comparing with the other plots. 3) Average length of plumule and radicle also was inhibited by ABA treatment. This means lower seedling vigor. 4) Fresh and dry weight of the seeding were higher in BA plot while ABA plot was lower and undesirable seedling was produced. From above mentioned results, it is believed that ABA treatment to the seed induced the secondary dormancy and physiological dwarf pattern. Therefore, utilization of BA can be produced the normal seedling, the authors believed.

• Korean Journal of Weed Science
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• v.16 no.3
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• pp.187-193
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• 1996

To supply seeds with a good quality as plant materials for herbicide screening and to know whether the germination characteristics could be associated with a differential response to herbicides, germination characteristics and differential responses to herbicides were investigated with 3 species of a genus Setaria ; Yellow foxtail(Setaria glauca P. Beauv, SETGL), Giant foxtail(Setaria faberi Hetrm, SETFA), and Green foxtail(Setaria viridis P. Beauv, SETVI). Degree of dormancy was high in the order of SETGL, SETVI and SETFA. The dormancy of SETGL seed was relatively well removed by room temperature and drying storage, but SETFA and SETVI by low temperature and wetting storage(stratification). For breaking dormancy of SETGL, SETVI and SETFA, it was necessary for being kept under the above storage conditions for at least 2, 4 and 4-5 months, respectively. When the dormancy-breaked seeds were transfered to low temperature($4^{\circ}C$) and drying condition, SETGL showed germination rate of 96% even after 2 month storage. However, SETVI and SETFA showed a decreased germination of 54% and 69%, respectively, with a decreased velocity of germination, indicating that secondary dormancy might be induced. On the other hand, a significant change in germination rate was not observed as the seeds were transfered to room temperature($25^{\circ}C$) and drying condition. The germinability of SETGL seed began to decline from 6th year after storage in room temperature and drying condition. All of 3 species showed relatively high germination rate at alternating temperature of $30^{\circ}C$/$20^{\circ}C$(14hr/10hr) and their germination were not increased by light. All of 3 species exhibited similar responses to cycloxydim, sethoxydim and primisulfuron in greenhouse experiment. In contrast, SETVI and SETFA were relatively susceptible to fenoxapropethyl, SETFA to fluazifop-butyl, SETGL and SETFA to clorimuron-ethyl, and SETGL to EK-2612. The difference in herbicidal response among 3 species was the highest in the treatment of EK-2612. These results suggest that there is no a consistent tendency in responses of 3 species to herbicides which have the same target site. And the relationship between germination characteristics and differential responses to herbicides was not found.

• Korean Journal of Weed Science
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• v.16 no.2
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• pp.88-99
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• 1996

In recent years dry direct-seeding of rice has been encouraged by the government and increasingly practiced by farmers in Korea. This has been bringing up an increased occurrence of weedy rites. Some farmers in the southern region dare to sow the rice before winter after harvest, while most farmers wish to sow as early as possible in the spring to secure the growing period, and to disperse the intensive labor in early May. The purpose of this study was to determine the feasibility of moving the sowing of rice to an earlier date under dry direct-seeding, and to elucidate the nature of emergence of an old strain of rice, weedy rites, and barnyardgrasses tinder this farming practice and their adaptive competence over present cultivate. The presently recommended rice cultivar, Dongjinbyo and an old rice strain, Dadajo which prevailed in early 1900s, almost could not emerge from soil deeper than 6cm and could emerge to only 5.3% at best from 1cm deep loamy soil field when the seeds were sown on Nov. 28. However, two strains of weedy rites being weedy for over 200 years emerged by 17.0 to 63.0% from the loamy and sandy clay loam field 1 to 6cm deep. Emergence of the weedy rites was greater in the loamy soil and at a shallow depth, and negligible from the soil depth of 9cm. Barnyardgrasses sown on Nov. 28 emerged by 13.4 to 51 % from the 1 to 3cm deep loamy soil, and 8.6 to 46.7% from the 1cm deep sandy clay loam. Echinochloa crus-galli var. crus-galli emerged more than var. praticola, and var. oryzicola least. Most of the non-emerged barnyardgrasses seem to have entered secondary dormancy. Seeding rice a month earlier than the season lowered the emergence of Dongjinbyo by ca. 10, 18, and 26%, respectively at 1, 3, and 6cm soil depths, indicating that moving the seeding date a month earlier is impractical. The old strain, Dadajo sown in the soil at a depth of 6cm responded similarly. However, the strain has shown a significantly higher ability in emergence from 9cm deep soil. Weedy rices sown a month earlier A month earlier sown weedy rices have shown very similar emergence rates at various soil depths to those sown on May 1. Barnyardgrasses have also shown similar emergence rates when sown between April 3 and May 1. Like barnyardgrasses, the old strain and weedy rices apparantly posessed a greater adaptability to emerge under lower temperatures, and from deeper soil ; Dongjinbyo${\leq}$ Echinochloa species in that order. However, emergence- speed under lower temperature(sown on April 3) was faster in the order of weedy rice