• KOREAN JOURNAL OF CROP SCIENCE
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• v.46 no.2
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• pp.69-77
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• 2001

'Chalok 1/Cooktail 51' corns, supersweet corn gene controlled by either brittle-l (bt l) or shrunken-2(sh2) gene introduced into waxy corn, showed agronomic characteristics between supersweet corn and waxy corn. The ears were harvested at different development stages from 15 to 35 days after silking (DAS). Ear diameter of Cocktail 51 and 'Cocktail 51'/Chalok 1 increased from 15 DAS to 30 DAS and little increased thereafter, but that of Chalok 1/Cocktail 51 and 'Chalok l' increased until 35 DAS. Diameter of ear extension increased more in Cocktail 51 and Chalok 1/Cocktail 51 corn than Chalok 1. Ear fresh weight of Cocktail 51 decreased later 30 DAS but those of the other hybrids were vice versa. Rate of super-sweet kernels per ear of Chalok 1/Cocktail 51 corns was about 38 %. Development, and elongation of kernel were much more prominent in supersweet kernel than in waxy kernel, but fresh weight increased higher in waxy kernel than supersweet kernel. Moisture content in kernel decreased from 15 DAS to 35 DAS. Total sugar content of the kernel increased until 25 DAS, and that of Cocktail 51 kernel showed the highest among of them. After cooked by steam, flavor and mastication feeling rate cooked by steam of Cocktail 51 and Chalok 1/Cocktail 51 were increased from 15 DAS to 25 DAS and markedly decreased thereafter. But those of Chalok l/Cocktail 51 and, Chalok 1 were decreased after 30 DAS. These results suggested that the optimum harvest date for fresh supersweet corn (Cocktail 51), Cocktail 51/Chalok 1 seems to be about 20 DAS and Chalok 1/Cocktail 51 and waxy com (Chalok 1) was about 25 DAS.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.3
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• pp.197-200
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• 1999

In order to get abundant germplasm for develop- ing new corn varieties, major morphological characteristics of ear were evaluated with a total of 210 Korean indigenous maize lines collected from various parts of Pusan City and Kyungnam Province, Korea. The ear shape of Korean indigenous maize was mainly cone type or similar to cone type. Cylinder type or similar to cylinder type of corn was collected from the north-west mountainous. region of Kyungnam Province, whereas cone type or similar to cone type was collected from the plain region. In the kernel colors of each ear, ears with mono colored kernels were 55.7% of the total, and ears with two to four mixed colors were 44.3%. Among the mono colored ears, brown was the most abundant at 16.8%. There was an average of 12∼14 rows per ear. Kernal rows per ear varied from 8∼20. Waxy corn was predominant at 67.2%, mixed corn with waxy kernel and common kernel at 11.0%, and common corn at 21.8%.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.1
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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.

• Korean Journal of Agricultural Science
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• v.4 no.2
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• pp.215-228
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• 1977

In order to provide good germplasm for developing good corn hybrids, a total of 948 Korean indigenous corn lines were collected from various parts of country and major morphological characterstics of ears were investigated. The results obtained were as follows; 1) Ear Type; From the east-north mountaionus region where more than 80% of total corn production is practiced, cylinder (type I) or similar types to cylinder corn were collected, and from the southern plain region, where rather small scales of corn is grown, cone type (type IV) or similar types to cone were prevalent. 2) Kernel color; In the ear colors of all the indigenous corn lines collected from ten regions, ears with mono color were 54.4%, ears with two color mixed were 39.0% and ears with three or more color mixed were 6.6%. In northern mountainous region, region A and region I, ear color was mostly white or white plus other colors, while in other regions ear color was yellow or yellow plus other colors. 3) Denting; Dent type was only 4.3% of Korean indigenous corn lines collected, and others were flint type. Dent type was collected from northern regions, where foreign corn varieties were introduced and grown. 4) Ear row number; Ear row numbers of indigenous corn lines collected were 12 to 16. There was no significant differences among the ear row numbers in a ear ciassified by regions. However, it was observed that ear row number was closely related to kernel size. For instance, the ears with 24 ear-rows were the smallest in kernel size. 5) Quality of starch; 70.9% of the indigenous corn lines collected were kernels with hard starch. Corn with soft starch was 26.0% and medium type was 3.1%. In region A and region I, where lot of corn is grown, corn with hard starch was more frequently collected. 6) Pop corn and waxy corn; In all the indigenous corn lines collected, popcorn was distributed uniformly through the regions except region I, and waxy corn was found more in the northern mountainous region. 7) Ear length; The mean ear length of indigenous corn lines collected was 13cm. In region A and region I ear length was larger than that in other regions. 8) Ear diameter; The mean ear diameter of indigenous corn lines collected was 3.3cm. In region A and region I ear diameter was larger than that in other regions. 9) Kernel length, kernel width and kernel thickness; The mean kernel length, kernel width and kernel thickness of indigenous corn lines collected were 0.82cm, 0.42cm, and 0.78cm, respectively. The kernel size in the region A and region I was larger than that in other regions. 10) Ear weight; The mean ear weight of indigenous corn lines collected was 58.04gr. Ear weight was remarkably heavier in region A and region I. The heaviest ear weighed 330gr, and the lightest ear weighed 5 gr. 11) Kernel weight of a ear and 100 kernel weight; Kernel weight of a ear and 100 kernel of indigenous corn lines collected were 47.07gr and 15.07gr, respectively. Kernel weights and 100 kernel weights were much heavier in region A and region I than other regions.

• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1521-1521
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• 2001

The objective of the research being presented was to construct and calibrate a spectrometer for the analysis of single kernels of corn. In light of the difficulties associated with capturing the spatial variability in composition of corn kernels by single-beam spectrometry, a hyperspectral imaging spectrometer was constructed with the intention that it would be used to analyze single kernels of corn for the prediction of moisture and oil content. The spectrometer operated in the range of 750- 1090 nanometers. After evaluating four methods of standardizing the output from the spectrometer, calibrations were made to predict whole-kernel moisture and oil content from the hyperspectral image data. A genetic algorithm was employed to reduce the number of wavelengths imaged and to optimize the calibrations. The final standard errors of prediction during cross-validation (SEPCV) were 1.22% and 1.25% for moisture and oil content, respectively. It was determined, by analysis of variance, that the accuracy and precision of single-kernel corn analysis by hyperspectral imaging is superior to the single kernel reference chemistry method (as tested).

• Korean Journal of Agricultural Science
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• v.39 no.1
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• pp.29-34
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• 2012

This study was carried out to identify the characteristics of 37 corn hybrids, which composed with 18 yellow colored kernel, 9 purple colored kernel, 8 white colored kernel. Days to silking of three colored waxy corn hybrids ranged from 61 to 73 days after sowing as midium-late ecotype. Ear length of hybrids ranged from 10.3 to 22.7 cm, and among them a total 22 waxy corn hybrids including CNU038 showed over 20 cm in ear length. The fresh weight per ear ranged from 58 to 289 g as the 32.9% of large coefficient of variance. In there results, we found yellow colored waxy corn hybrids showed relatively longer in ear length and heavier in fresh weight per ear compare to other colored waxy corn hybrids. In correlation relationships, plant height, ear height, stem diameter, ear length and ear weight showed positive correlation between themselves, while tip filling ratio did negative correlation with silking stage, plant height, ear length, ear weight and kernel thickness. Also, 100 kernel weight did positive correlation between traits related to ear and kernel.

• Korean Journal of Agricultural Science
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• v.43 no.5
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• pp.761-768
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• 2016

Recently, swine production costs have increased due to increased feed cost, especially the price of corn and soybean meals. Soybean meal is traditionally an expensive ingredient, but the price of corn has dramatically increased because of increased biofuel production. This change has resulted in the swine industry looking for alternatives in order to reduce feed cost, resulting in decreased production costs. Thus, various alternatives have been used as feed ingredients to replace corn, soybean meal, or other expensive ingredients. One othercandidate may be palm kernel co-products that are a by-product of oil extraction from palm fruits. Palm kernel co-products have not been used in swine diets due to high fiber content and imbalanced amino acids compared with corn and soybean meal. However, recent studies showed that palm kernel co-products did not have any negative effects on growth performance of pigs when they replaced some proportions of corn and soybean meal. In addition, palm kernel co-products may provide some physiological properties to pigs by modifying gut microbiota and/or immunity of pigs, resulting in improvement of growth and health of pigs. Therefore, the value of palm kernel co-products were reviewed as one of the alternatives for corn, soybean meal, or other major ingredients in swine diets.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.59 no.1
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• pp.73-82
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• 2014

This study was conducted to investigate the ear and kernel characteristics of waxy corn during ripening by double cropping, and to understand the pattern of starch accumulation in endosperm of waxy corn kernels. Chalok4 and Ilmichal were sown at April 20 (first cropping) and July 20 (second cropping) in 2011~2012. The accumulated temperature from silking to harvesting was about $590{\sim}630^{\circ}C$. It takes 23~24 days when Chalok4 and Ilmichal were sown in April 20, but July 20 sowing takes 32~35 days. Ear length and kernel set length were significantly shorter in second cropping (p<0.05). Kernel length, kernel width, 100-kernel weight, and starch content of waxy corn were increased as ears matured (p<0.05). Growth temperature was getting decreased during the ripening stage of second cropping, the rate of ear and kernel development had slowed. Starch granules started to accumulate in the cells around the pericarp, then developed in the cells around the embryo. In the second cropping, starch granules in the kernel of waxy corn were less compact than the first cropping, harvesting time of waxy corns can be extended. These results will be helpful to farmers for double cropping of waxy corn cultivation and management.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.45 no.1
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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.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.2
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• pp.102-108
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• 2019

Pericarp thickness of vegetable corns such as sweet and waxy corn is one of the crucial traits, contributing to their edible quality. This study was carried out to compare the pericarp thickness of super sweet and waxy corn hybrids measured with kernel samples prepared using different methods at different grain filling periods. The samples comprised excised pericarp from dried, frozen (at $-4^{\circ}C$), and fresh kernels. Analysis of variance performed separately on super sweet and waxy corn hybrids indicated a significant three-way interaction among cultivars, kernel sample preparation methods, and days after pollination (DAP). Dried samples of super sweet corn hybrids presented reasonably stable pericarp thickness measurements during grain filling, while all the sample preparation methods fluctuated less as grains of waxy corn hybrids matured. Waxy corn is best consumed at around 24 days after pollination. Pericarp thickness of waxy kernel samples regardless of preparation methods investigated was the same at 24 DAP with a few exceptions. Overall, the common method of drying kernel samples before pericarp excision can provide reliable data for estimating the tenderness of vegetable corn hybrids.