• Title/Summary/Keyword: leaves maturity

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Occurrence of Rhizopus Soft Rot on Squash (Cucurbita moschata) Caused by Rhizopus stolonifer in Korea

  • Kwon, Jin-Hyeuk;Kang, Soo-Woong;Park, Chang-Seuk
    • The Plant Pathology Journal
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    • v.16 no.6
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    • pp.321-324
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    • 2000
  • season of 2000. The disease infection usually started from flower, peduncle and young fruits, then moved to flower stalk, stem and leaves. At first, the lesions started with water-soaked, rapidly softened, and then the area gradually expanded. In severely affected film house, the rate of infected fruits reached to 28.6%. Numerous sporangiospores were formed on the diseased fruits, flower stalk, stem and leaves. Most of the sporangiospores were appeare to be rapidly dispersed in the air. The mycelia grew on the surface of host and formed stolons. Colonies on potato dextrose agar were cottony at first brownish black at maturity. Sporangia were 125.3${\times}$294.2 ${\mu}$m. globose or sub-globose with somewhat flattened base. White at first the black, many spored, and are never overhanging. Sporangiophores were 2.7-6.8${\times}$12.9-33.9 ${\mu}$m, smooth-walled, non-septate, light brown, simple, long, arising in groups of 3-5 from stolons opposite rhizoids. Sporangiophores were 8.6-21.1${\times}$6.41-1.7 ${\mu}$m, irregular, round, oval, elongate, angular and brownish-black streaked. Columella were 63.8${\times}$140.4 ${\mu}$m. brownish gray, umberella-shaped when dehisced. The causal organism was identified as Rhizopus stolonifer Lind on the basis of the morphological characteristics of the fungus. Rhizopus soft rot on squash (Cucurbita moschata) caused by the fungi has not been previously reported in Korea.

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Studies on Corn-Legume Intercropping System I. Growth charateristics, dry matter and organic matter yield of corn (Zea mays L.)-cowpea (Vigna sinensis King) intercropping (Silage용 옥수수와 두과작물의 간작에 관한 연구 I. Silage용 옥수수 ( Zea mays L. ) 동부 ( Vigna sinensis King ) 의 간작이 생육특성과 건물 및 유기물수량에 미치는 영향)

  • 이성규
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.8 no.1
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    • pp.47-54
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    • 1988
  • The growth characteristics and yield per unit area of two cultivation systems of forage, corn (Zea mays L.) monoculture and corn-cowpea (Vigna sinesis King) inter-cropping were compared and obtained follow results. 1. The two cultivation systems were not significantly different in leaf length, leaf width and length of internode with harvesting time. 2. The weight of stalk and leaves of a plant were decreased with maturity, while weight of ear was markedly increased. The patterns of relative ratio of each components was essentially same in each cultivation system. In corn monocrop., the percentages of stalk, leaf and ear at final harvesting stage were 22.9, 13.7 and 63.4, respectively. 3. Dry matter yield per unit area (33kgIlOa) of intercropped corn at yellow stage was similar to that of monocropped corn ( l,482.8kg/ 10a vs 1 ,SO8.9kg/ 10a). At ripe stage, however, the DM yield of intercrop. was higher than that of monocrop. (1,810.4kg/lOa vs 1,660.4 kg/ 1 Oa). 4. The same pattern was observed in organic matter yield.

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Growth and Quality Responses of Flue-cured Tobacco to Phosphate bevels in the Field Experiment (토양중 인산함량 및 인산시비량이 담배의 생육 및 품질에 미치는 영향)

  • Park, Su-Jun;Choi, Jyung
    • Journal of the Korean Society of Tobacco Science
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    • v.2 no.1
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    • pp.68-77
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    • 1980
  • Field experiment was conducted in soils having different amount of available phosphate (35, 140 and 350ppm) to see effects of additional phosphate application(0, 5, 10, 15, 20 and 30kg/10a) on yield and quality of flue-cured tobacco. Growth was affected by additional phosphate application only in soil with 35ppm of available phosphate, as was dry weight of tobacco. Maturity and content of chemical constituents of tobacco leaves were not significantly influenced by additional phosphate treatments. Tobacco leaf production increases with additional phosphate up to 10kg/10a only in soil with the lowest amount of available phosphate, but the price was not affected at all. These results suggest that art applicable phosphate of about 10kg/10a is enough for maximum production of flue-cured tobacco even soil very low in available phosphate.

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Effect of Soil Conditioners on the Growth, Yield and Quality of Flue-cured Tobacco (토양 개량제 시용이 연초의 생육, 수량 및 품질에 미치는 영향)

  • Kim, Yong-Ok;Choi, Jyung
    • Journal of the Korean Society of Tobacco Science
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    • v.5 no.1
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    • pp.87-95
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    • 1983
  • This study was conducted to evaluate the affect of soil conditioners and their application rates on the growth, Yield and quality of Flue-cured tobacco. Soil conditioners for this study were Montmorillonite arid Zeolite as clay mineral source and Rice hull and Sawdust as organic source. Their application rates were 500, 1000, 2000kg/10a. The growth of tobacco plants was promoted, compared with that of Non- treated plot (control) by Zeolite, Montmorillonite and Rice hull application but decreased by Sawdust application. During tobacco growing season soil moisture content, compared with control, was increased by Zeolite and Montmorillonite application but decreased by Rice hull and Sawdust application. In contrast to soil moisture content, soil temperature was higher in the Rice hull and Sawdust plot than in the plot of Zeolite and Montmorillonite. The treatment of Sawdust, compared with control, obviously accelerated the maturity of tobacco, increased reducing Sugar but decreased total alkaloids, nicotine and nitrogen content of cured leaves. The Sawdust Plot decreased the Yield (kg/10a) with significant difference by 1 %level but significantly increased leaf quality (Won/kg) and value (Won/10a) by 1%and 5 %level, respectively. The present application , ate of Nitrogen in Korea (12.5kg/10a) seems to be excessive for Flue-cured tobacco production.

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Studies on Corn-Legume Intercropping System III. Growth charateristics, dry matter and organic matter yield in corn(Zea mays L.) and soybean(Glycine max L. Merr) intercropping (Silage용 옥수수와 두과작물의 간작에 관한 연구 I. Silage용 옥수수 ( Zea mays L. ) 동부 ( Vigna sinensis King ) 의 간작이 생육특성과 건물 및 유기물 수량에 미치는 영향)

  • 이성규
    • Journal of The Korean Society of Grassland and Forage Science
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    • v.8 no.3
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    • pp.158-164
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    • 1988
  • The growth characteristics and yield per unit area of two cropping systems, corn monoculture and 'wrnsoybean intercropping, were compared and the obtained results were as follows; 1.The two cultivation systems were not significantly different in leaf length, leaf width and length of internode at harvesting time. 2.The weight of stalk and the leaves of a plant were decreased with maturity, while the weight of ear was markedly increased. The patterns of relative ratio of each components were essentialy same in each cultivation systems. In corn monoculture, the percentages of stalk, leaf, and ear at final harvesting stage were 22.9, 13.7, and 63.4 and in corn-soybean intercropping, they were 21.8, 10.9, and 67.3 respectively. 3.Dry matter yield per unit area (kg/lOa) of intercropped corn at yellow stage was similar to that of monocultured corn (1, 483 kg/ 10a vs 1, 509 kg/ 10a). At ripe stage, however, the dry matter yield of intercropped plant was more than that of monocultured (1, 679 vs 1, 660 kg/ 10a). 4.The same pattern was observed in organic matter yield.

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Dose Effect of Phytosanitary Irradiation on the Postharvest Quality of Cut Flowers

  • Kwon, Song;Kwon, Hye Jin;Ryu, Ju Hyun;Kim, Yu Ri
    • Journal of People, Plants, and Environment
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    • v.23 no.2
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    • pp.171-178
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    • 2020
  • The present study was conducted to determine the effects of electron beam irradiation on the postharvest quality of cut flowers. Cut flowers were irradiated with electron beam at 100, 200, 400, 600, 800, 1,000, and 2,000 Gy with a 10 MeV linear electron beam accelerator to evaluate their irradiation tolerance. Postharvest quality was determined by monitoring fresh weight loss, flower longevity, flower diameter, flowering rate, visual quality of flowers and leaves, and chlorophyll content. Cut flowers showed a radiation-induced damage with increasing the irradiation dose. Flower longevity and fresh weight of cut flowers decreased when the irradiation dose was increased. Flower bud opening was also inhibited in a dose-dependent manner. The effective irradiation doses for 10% reduction of postharvest quality (ED10) values were 144.4, 451.6, and 841.2 Gy in the 'Medusa' lily, 'Montezuma' carnation, and 'Rosina White' eustoma, respectively. Although tolerance of cut flowers to electron beam irradiation vary according to species, cultivars, or maturity stage conditions, it is conceivable that 'Montezuma' carnation and 'Rosina White' eustoma could be tolerated and maintained overall postharvest quality up to 400 Gy, the generic irradiation dose approved by the Animal and Plant Health Inspection Service (APHIS) and the International Plant Protection Convention (IPPC) for postharvest phytosanitary treatments.

Studies on the Breeding of the Response to short photoperiod, Fiber weight, and Qualitative characters and of the Associations Among these characters in Kenaf (섬유용양마의 육종에 관한 연구 -단일반응성과 섬유종의 유전 및 연소)

  • Johng-Moon Park
    • KOREAN JOURNAL OF CROP SCIENCE
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    • v.4 no.1
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    • pp.115-124
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    • 1968
  • It was shown that the most desirable characters for kenaf are high-fiber weight and moderately early maturity. Therefore, the objectives of this research on this crop is to find varieties possessing these characteristics. The experiments covered in this report provided new information relative to segregation, mode of inheritance, estimate of the number of genes involved in fiber weight and their response to short day length of 10 hours and the qualitative characters, such as, color of stem, capsule, petiole and shape of leaves. The associations which exist among these characters are also indicated. Fiber weight per plant, days to flowering, Stem color, Petiole color, Capsule color, and shape of leaves were studied in parental, $F_1$.$F_2$and backcross populations of a cross between Dashkent, a low-fiber weight but early maturing kenaf variety, and G 38 F-1, a high-fiber weight but late maturing kenaf variety. Crosses were made using the varieties, Dashkent and G 38 F-1 as parents. The Dashkent parent had the following characteristics: green stems, capsules and petioles and lobed shaped leaves; 105.8234 mean-days to flowering in the field, and 106.9222 mean-days under 10 hours short day treatment. The other parent, G 38 F-1 had red stems yellow capsules and red petioles and unlobed shaped leaves; 149.8921 mean-days to flowering in the field, and 62.3684 mean-days under 10 hours short day treatment. Both of the parents, $F_1$, $F_2$, $BC_1$ ($F_1$ X Dashkent, ) and $BC_2$($F_1$ ${\times}$ G38F-1) of the kenaf cross were grown at the Crops Experiment Station, Suwon, Korea in 1965. Color of stems, petioles and capsules, and shape of leaves were noted to be simply inherited as a single factor. Red stem color was dominant over green stem color, red petiole color was dominant over green petiole, lobed shaped leaves were dominant over unlobed shaped leaves and yellow capsules were dominant over green capsule. It was, also, noted that the factor for color of petiole was linked with the factor for shape of leaf with a 11.9587 percent recombination value, however no interaction or linkage were found among the color of stem and capsule color. Using Powers partitioning method, theoretical means and frequency distributions for each population, the days to flowering were calculated with the assumption that two gene pairs were involved. The values obtained fitted the theoretical values. In general this would indicate that Dashkent and G 38 F -1 were differentiated by two gene pairs. Heritability values were calculated as the percent of additive genetic variance. Heritability value of days to flowering, 89.5% in the broad sense and 79.91% in the narrow sense, indicated that the selection for this character would be effective in relatively early generations. Particularly, high positive correlations were found between days to flowering and the color of petioles and shape of leaves. However, there was no relation between days to flowering and capsule color nor between these and stem color. On the basis of the results of this experiment there is evidence that the hereditary factor for shape of leaves and the color of petioles is linked with an effective factor or factors for the characters of days to flowering. The association was sufficiently close to offer a possible simple and efficient means of selection for moderately early mat. uring plants by leaf shape and petiole color selection. Again using Powers partitioning method the frequency distribution for each population to the fiber weight were calculated with the assumption that two gene pairs, AaBb, were involved. Both phenotypic and genotypic dominance were complete. The obtained value did not agree with the theoretical value for $F_2$ and $BC_1$ ($F_1$ ${\times}$ Dashkent.) It seems that Dashkent and G 38 F-1 were differentiated by two major gene pairs but some the other minor genes are necessary. It is certain that the hereditary factor for shape of leaves and color of petioles is linked with an effective factor or factors for fiber weight. Also, high. yielding plants with moderately early maturity were found in the $F_2$ population. Thus, simultaneous selection for high-fiber yield and moderately early maturing plants should be possible in these populations. Phenotypic and genotypic correlation coefficients between fiber weight per plant and days to flowering, stem height and stem diameter were calculated. In general, genotypic correlations are higher than the phenotypic correlation. The highest correlation is found between stem height and fiber weight per plant (0.7852 in genotypic and 0.4103 in phenotypic) and between days to flowering and fiber weight per plant (0.7398 in genotypic and 0.3983 in phenotypic.) It was also expected that the selection of high stem height and moderately early maturing plants were given the efficient means of selection for high fiber weight.

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Evaluation of Site-specific Potential for Rice Production in Korea under the Changing Climate (지구온난화에 따른 우리나라 벼농사지대의 생산성 재평가)

  • Chung, U-Ran;Cho, Kyung-Sook;Lee, Byun-Woo
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.8 no.4
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    • pp.229-241
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    • 2006
  • Global air temperature has risen by $0.6^{\circ}C$ over the last one hundred years due to increased atmospheric greenhouse gases. Moreover, this global warming trend is projected to continue in the future. This study was carried out to evaluate spatial variations in rice production areas by simulating rice-growth and development with projected high resolution climate data in Korea far 2011-2100, which was geospatially interpolated from the 25 km gridded data based on the IPCC SRES A2 emission scenario. Satellite remote sensing data were used to pinpoint the rice-growing areas, and corresponding climate data were aggregated to represent the official 'crop reporting county'. For the simulation experiment, we used a CERES-Rice model modified by introducing two equations to calculate the leaf appearance rate based on the effective temperature and existing leaf number and the final number of leaves based on day-length in the photoperiod sensitive phase of rice. We tested the performance of this model using data-sets obtained from transplanting dates and nitrogen fertilization rates experiments over three years (2002 to 2004). The simulation results showed a good performance of this model in heading date prediction [$R^2$=0.9586 for early (Odaebyeo), $R^2$=0.9681 for medium (Hwasungbyeo), and $R^2$=0.9477 for late (Dongjinbyeo) maturity cultivars]. A modified version of CERES-Rice was used to simulate the growth and development of three Japonica varieties, representing early, medium, and late maturity classes, to project crop status for climatological normal years between 2011 and 2100. In order to compare the temporal changes, three sets of data representing 3 climatological years (2011-2040, 2041-2070, and 2071-2100) were successively used to run the model. Simulated growth and yield data of the three Japonica cultivars under the observed climate for 1971-2000 was set as a reference. Compared with the current normal, heading date was accelerated by 7 days for 2011-2040 and 20 days for 2071-2100. Physiological maturity was accelerated by 15 days for 2011-2040 and 30 days for 2071-2100. Rice yield was in general reduced by 6-25%, 3-26%, and 3-25% per 10a in early, medium, and late maturity classes, respectively. However, mid to late maturing varieties showed an increased yield in northern Gyeonggi Province and in most of Kwangwon Province in 2071-2100.

Influence of degree of maturity and duration of cold treatment on the growth and flowering of L. elegans 'Connecticut King' bulb (Lilium elegans 'Connecticut King'의 촉성재배(促成栽培)에 있어서 구근(球根)의 숙도(熟度) 및 저온처리기간(低溫處理期間)이 생육(生育) 및 개화(開花)에 미치는 영향(影響))

  • Lee, Jeng;Shin, Hak Ki;Choi, Sang Tai
    • Current Research on Agriculture and Life Sciences
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    • v.9
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    • pp.147-155
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    • 1991
  • Effects of harvest date, number of the leaves remained on stump after flower cutting, duration of cold treatment on the growth and flowering of L. elegans 'Connecticut King' bulb were tested. Shoot emerging rate increased over 90% by delayed cold treatment, late harvesting time and more leaves remained. Flowering rate increased over 90% when conducted cold treatment of 90 days to the premature bulb at flowering date, the bulb matured for 50 days with 10 leaves and the bulb matured for over 30 days with 20 leaves, and when conducted cold treatment of 50 days to the bulb matured for over 30 days with all leaves. Delayed cold treatment duration shortened days needed to shoot emergence and flowering. Especially days to flower of the premature bulb at flowering date were the shortest of all treatments, and can be flowered within 100 days after planting. In generally, plant height, number of flowers per plant and stem diameter generally increased by longer bulb maturing period after flower cuting, and the premature bulb harvested at flowering date showed poor growing and flowering responses. But, if used the larger size bulb, it is believed that the prematured bulb can be forced to flower normally in current year without bulb maturing period.

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Ecology of Disease Outbreak of Circular Leaf Spot of Persimmon and Inoculum Dynamics of Mycosphaerella nawae (감나무 둥근무늬낙엽병의 발생과 병원균(Mycosphaerella nawae)의 전염원 동태)

  • Kwon, Jin-Hyeuk;Park, Chang-Seuk
    • Research in Plant Disease
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    • v.10 no.4
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    • pp.209-216
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    • 2004
  • The circular leaf spot of persimmon is occurred almost every place where persimmon is cultivated, especially the disease outbreak severely in southern part of Korea. The disease reveals unusually long incubation period after pathogen invade into leaf tissue and no practical control measure is available once the symptom has appeared. Most of the farmers just follow the suggested spray schedules calculated on the basis of weather condition of ordinary years. Therefore the damages due to circular leaf spot greatly differ year after year. In this article, we tried to describe and summarized the investigation on the circular leaf spot pathogen, Mycosphaerella nawae, related to disease outbreak such as overwintering of pathogen, inoculum formation and spread, incubation period after infection, and secondary inoculum. With the summary of these results, we suggest the disease cycle of circular leaf spot of persimmon. The pathogen overwinters in diseased leaves as mycelial form or pseudoperithecial premodium. The pseudoperitheria become matured in spring as the temperature raise and forms asci and ascospores. The maturation of pseudoperithecia are closely related to the temperatures during March and early April. The ascospores completely mature in early May and the ascospores released when the pseudoperithecia absorbed enough moisture after rainfall. The release of ascospores are diverse greatly with the variation of maturity of pseudoperithecia. Generally the spore start to release from middle of May to early of July. Duration of ascospore release is depend on the weather condition of particular year, especially amount and number of precipitation. The ascospores produced from pseudoperithecia is known to the only inoculum for circular leaf spot disease. But according to the results obtained from our investigations, the conidia formed on the lesions which incited by natural infection. This conidia are infectious to persimmon leaves and formed identical symptom as natural infection. The time of producing secondary inoculum of circular leaf spot of persimmon is considered too late to develop new disease. Generally the importance of secondary inoculum is low but the conidia produced in early September are competent to develop new disease and new infection also significantly affect to harvest of persimmon. The importance of circular leaf spot disease is recognized well to farmers. The approaches to control of the disease should be initiated on the basis of the knowledges of inoculum dynamics and ecology of disease development. The forecasting system for circular leaf spot is need to be developed.