• 한국작물학회지
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• 제50권2호
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• pp.91-96
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• 2005

Proper choice of source populations contributes to the ultimate success of selection for genetic improvement. The source population should possess the most desirable alleles at as many loci as possible for intra population improvement. Such desirable alleles can be intensified by introgression of exotic germ plasm into locally adapted ones through hybridization followed by selection. The objectives of this study were to determine the mean performance, genetic variability $({\sigma}^2G)$ and heritability of fresh ear yield and other important traits within two sweet corn source populations, $BC1-10{\times}Syn-II$ and BC2-10. One hundred selfed progenies from each of the two source populations were evaluated in a $10\times10$ lattice design, at the Institute of Bioscience (IBS) Farm, University of Putra Malaysia (UPM) following the recommended cultural practices. Significant differences among selfed progenies within $BC1-10{\times}Syn-II$ were observed for all traits, while differences among selfed progenies within BC2-10 were noted for fresh ear yield, ear length, ear diameter, number of kernels per row, ear height, days to tasseling and days to silking. Progenies developed from $BC1-10{\times}Syn-II$ population had higher estimates of ${\sigma}^2G$ than did progenies from BC2-10 population for number of kernel rows per ear, total soluble solids, plant height, days to tasseling and days to silking, showing that selection to improve these traits would be more effective in selfed progenies of $BC1-10{\times}Syn-II$ than that in BC2-10. On the other hand, progenies developed from BC2-10 population had higher estimates of ${\sigma}^2G$ for ear length, ear diameter and ear height, indicating that progenies from this population would have better genetic gain than $BC1-10{\times}Syn-II$. Comparable estimates of genetic variance were found for fresh ear yield, and number of kernels per row, indicating that genetic improvement of the two source populations is expected to produce similar genetic gains for these two traits. Therefore, selfed progenies developed from both source populations could be used to improve the two populations for various traits and thereby develop superior genotypes for immediate use in the production system.

• 한국작물학회지
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• 제46권4호
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• pp.266-271
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• 2001

Soybean can produce high-N residue due to N-fixation, so soybean rotation may increase yield of subsequent corn and reduce N fertilizer on the corn fairly. To find out the contribution of nitrogen to subsequent corn following soybean cultivation, soil nitrate, corn yield, and nitrogen uptake were measured for three continuous corn cropping years after soybean rotation. Three N rates of 0, 80, and 160 kg/ha were applied to three continuous corn following soybean cropping. At 6-leaf stage, soil nitrate amount at the soil depth of 0-30cm ranged from 60 to 80 kgN/ha higher in the first corn cropping year than that in the second and third corn cropping years. Judging from corn N status such as SPAD value, N concentration of ear-leaf and stover at silking stage, N contribution of previous soybean to corn in the first corn year was N fertilizer of approximately 80 kg N/ha. Stover N uptake at silking stage increased from 47 to 52 kg N/ha at the 0, and 80 kg N/ha of N rates in the first corn cropping year compared with those in the second and third corn cropping years. Corn grain yield at the 0 kg N/ha of N rate was 6-7 ton/ha higher in the first corn cropping year than that in the second and third corn cropping years, respectively. When compared the first corn year following soybean cropping with the second and third corn cropping years, N uptake of grain and stover at harvest with low N rates such as 0 and 80 kg N/ha increased from 45 to 67kg N/ha, from 35 to 60 kg N/ha, respectively. N uptake of whole plant by soybean rotation increased from 93 to 118 kg N/ha in the first year compared with that in the second and third corn cropping years. However, the N contribution by soybean cropping was small in the second and third continuous corn cropping years. Therefore, it was concluded that the nitrogen fertilizer of 80-100 kg N/ha in the first corn cropping year could be saved by soybean rotation and annual alternative corn-soybean rotation could be the best rotation system.

• 한국토양비료학회지
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• 제38권4호
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• pp.211-217
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• 2005

미사식양토에서 질소로 $240kg\;ha^{-1}$에 상당하는 생헤어리뱃치와 화학비료 초안(질산암모늄)을 옥수수 파종 1주일 전에 토양에 혼입하고 옥수수를 재배하면서 토양 무기태질소, 미생물태질소, 옥수수 지상부의 질소 집적량을 1997년부터 2년간 조사하였다. 헤어리벳치의 초기분해 시 초안 유래의 질산태질소의 60-70%에 달하는 질소량이 헤어리뱃치로부터 무기화되어 토층 0-15 cm에 집적되었다. 또한 토양미생물태 질소도 헤어리뱃치구가 초안구보다 $10-20mg\;kg^{-1}$ 증가하였으며 약간의 헤어리뱃치 유래 토양무기태 질소는 천천히 무기화되어 출사기 이후까지 옥수수에 공급되는 것으로 보였다. 출사기에서의 옥수수의 전체 질소 집적량은 2년간 모두 두 질소원 간에 차이가 없었다. 옥수수 수확기의 질소 집적량은 1997년도에는 헤어리뱃치 녹비구가 초안구보다 8% 적었지만 1998년도는 오히려 19% 증가하였다. 질소원으로서 $240kg\;N\;ha^{-1}$에 달하는 헤어리벳치녹비의 시용은 완효적인 질소무기화 효과를 나타내었으며 같은 량의 질소 화학비료를 대체할 수 있는 옥수수 생육촉진 효과를 보였다.

• 한국작물학회지
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• 제28권2호
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• pp.227-232
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• 1983

단교잡종 옥수수인 수원 19호(일반형)와 수원 58호(직립형)를 10a당 4,000, 5,500, 7,000, 8,500 본의 비율로 각각 5월 4일, 5월 25일, 6월 15일에 파종하여 파종기와 재식밀도가 옥수수 및 수량형질에 미치는 영향을 검토한 결과를 요약하면 다음과 같다. 1. 파종에서 출사까지 일수는 5월 4일 파종구가 74일이였으나 파종기가 지연됨에 따라 감소하여 6월 15일 파종에서 58일로 단축되었고 밀식에 의하여 출사기가 1일 늦어졌다. 파종에서 출사까지 기간을 유효적산온도로 표시하면 어느 시기에 파종하더라도 약 $810^{\circ}C$가 소요되었다. 2. 100본당 이삭수와 수당립수는 재식밀도가 증가함에 따라 직선적으로 감소되었다. 3. 5월 4일과 5월 25일 파종한 수원 19호의 100립중은 밀식할수록 직선적인 감소를 보였으나 수원 58호의 100립중은 어느 파종기에서도 재식밀도간 유의한 차이가 없었다. 4. 파종이 지연됨에 따라 두 교잡종의 종실수량은 크게 감소하였으며 특히 수원 58호가 현저하였다. 5. Duncan의 방법에 의하여 추정한 적정재식밀도는 수원 19호가 5월 4일과 25일 파종시에는 10a당 약 5,500본이고 6월 15일 파종에서는 3,200본이었다. 수원 58호는 5월 4일 파종구가 약 7,100 본, 5월 25일 파종구가 약 5,400본이었다.

• 한국초지조사료학회지
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• 제13권2호
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• pp.122-131
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• 1993

This study was conducted in 1991 and 1992 to determine the effects of winter annual forage corps such as winter rye (Secale cereale L.), rape (Brassica napus subsp. oleifera L.), oats (Auena satiua L.), crimson clover (Trifolium incarnatum L.), vetch (Vicia satiua L.) and Italian ryegrass (Lolim multiflorum Lam.) on subsequent growth, yield and quality of silage corn (Zea mays L.). The winter annual forage crops were seeded at the end of August and harvested in the fall and spring before corn planting. Corn-leaf numbers, plant heights and LA1 were generally reduced during early development when corn followed Italian ryegrass(P<0.05) and winter rye, but the silking date of corn was not affected by the winter annual forage crops. Corn dry matter and TDN yields were significantly reduced when corn followed Italian ryegrass and late maturing Kodiak winter rye. The yield reductions for corn following Italian ryegrass and Kodiak winter rye, relative to corn which did not follow the winter annual forage crops, were 49 and 19% respectively. but the corn yield was slightly improved by 2 and 3%, respectively. when corn followed crimson clover and vetch. No quality differences in corn stover were observed among the treatments except for the lowest ADF and NDF contents and the highest IVDMD where corn followed ltaliabn ryegrass.

• 한국작물학회지
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• 제47권5호
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• pp.384-389
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• 2002

No-tillage (NT) practice for corn production has advantages of reduction of soil erosion and energy conservation. Research on effects of NT for sweet corn or super sweet corn is very limited. Hybrids of sugary (su) and shrunken-2 (sh2) were tested under NT and conventional tillage (CT) practices to investigate plant characters, ear characters, fresh yield, and grain yield. Sugary hybrids were Golden Cross Bantam 70 (GCB70), Sprint, Geumdanok, and Danok3. Shrunken-2 hybrids were BSS9472, Cambella90, GSS9299, Jubilee, KS-Y-65, and Chodangok1. Emergence rates under NT were lower than those under CT for su, while there was no difference between tillage systems for sh2. There were no differences between CT and NT for days to tasseling and silking, plant height, and ear height for both su and sh2. Ear characters such as ear length, number of kernel rows, number of kernels per row, and t100-kernel weight under NT were not significantly different from those under CT. There were no differences between two tillage practice for fresh and grain yield, rather they showed trend of increases under NT practices. Results from this trial indicate that NT practice for both su and sh2 cultivation may be possible to recommend to farmers.

• 한국작물학회지
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• 제45권1호
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• pp.55-58
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• 2000

Germination of sweet and super sweet corn is lower than normal corn due to the higher sugar and lower starch contents of kernels. Sweet corn seeds are easily deteriorated in the field under the unfavorable condition, therefore it is important to identify the optimal harvesting time for seed production. This trial was conducted to investigate the responses of germination percentage of shrunken-2(sh2), brittle(bt), sugary(su), and sugary enhancer(se) hybrids in relation to harvesting dates. Eight hybrids of four different gene sweet corns were harvested at 15, 20, 25, 30, 35, 40, 45, and 50 days after silking(DAS). Germination test was performed using paper towel method. Mean germination percentages across eight hybrids showed the highest value at 45 DAS. There were significant differences among genes and within gene for germination. Shrunken-2 hybrid Mecca was higher than su hybrids for germination, indicating that sh2 would not be poorer than su Late harvesting beyond the optimal harvesting date might not be desirable because of more lodging and ear rots. Theoretical optimal harvesting date estimated from the regression equation was 40.9 DAS, however, practical date for harvesting would be a few days later than the estimated date if seedling vigor might be considered. Kernel dry weight per ear showed similar response to germination. Regression equation showed the highest kernel dry weight at 40.7 DAS. Significant correlations between kernel dry weight and germination were observed, impling that kernel dry matter accumulation would be an important factor for germination.

• 한국초지조사료학회지
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• 제17권1호
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• pp.59-66
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• 1997

This experiment was conducted at the forage experimental field, College of Agriculture and Life Sciences, Seoul National University, Suweon in 1992 and 1993 to investigate the effects of tillage method-conventional and rotary-till, rye (Secde cereale L.) harvest date-early (April 14) and late (April 26), and rye residue treatmentno paraquat(1, 1-dinethyl-4,4'-bipyridinium dichloride) and paraquat in minimizing the adverse effects of the rye residue on growth and yield of succeeding corn(Zea mays L.). Corn plant height during the growing season was slighly taller with conventional tillage relative to rotary-till when rye was harvested in early and treated by paraquat. Corn LA1 during the growing season was slighly increased when rye was harvested in early and where conventional tillage was used with paraquat treatment. There were no differences in the leaf number and silking dates of corn among the tillage methods, harvest dates of rye and paraquat treatments. The dry matter yield of corn was significantly increased by paraquat treatment when rye was harvest in early, but no differences were found in the dry matter percentage, ear percent to total dry matter, and stover, ear and estimated TDN yields of corn among the treatments.

• 한국작물학회지
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• 제43권1호
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• pp.15-18
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• 1998

Receptivity of corn silk to pollen decreases with time. For effective pollination, it is important to study the receptivity of corn silks in relation to time elapsed after their emergence. Two commercial corn hybrids, 'Kwanganog' and 'Suwon 19', were tested for their silk growth and effects of delayed pollination on kernel development for 1 to 13 days after emergence of the first silk. Silks elongated rapidly for the first 3 days and then gradually decreased. Silks grew more than 30mm per day for the first 3 days and stopped growing on the 11 or 12th day after emergence of the first silk. Filled ear length decreased slowly for the first 8 days, and then decreased rapidly. Similar trends were observed for number of kernel rows and number of kernels per row or ear. The highest numbers of kernels per row or ear were observed when plants were pollinated 2-4 days after silking. These numbers decreased gradually up to 8 days, and then decreased sharply. This result indicates that 8 day-delayed pollination has no influence on kernel development. There were negative correlations between silk length and ear characteristics except kernel weight. Silk growth rate was positively correlated with filled ear length, row number, and kernel number. It might be assumed that delayed pollination by one week after the first silk emerged would not affect on kernel set.

• 한국작물학회지
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• 제46권4호
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• pp.317-320
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• 2001

Sweet com seeds deteriorate faster due to low starch content than field com seeds when stored for a long tenn. This study had been conducted to observe the seed deterioration of four different sweet corns in a long tenn storage conditions in room temperature. Four kinds of sweet com genes (sh2, bt, su, and se) were harvested from 15 days to 50 days after silking with 5-day intervals. These seeds were stored in the room temperature and tested for germination percentages from 3 months to 18 months period with 3-month interval. su seeds germinated better than other types of gene. Hybrid Mecca which is sh2 gene germinated better when stored for 3 months to 18 months. For all genes, mean regression equations in relation to storage periods showed linear responses. For regression equation, the slope of sh2 gene was lower than that of su gene. The highest slope value was observed in bt gene showing faster deterioration rate. The rate at which seed deteriorates seems to be affected by the date at which it was harvested. The seeds that were harvested at the optimum time deteriorated more slowly than those which were not.