• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.2
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• pp.180-184
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• 2015

For waxy corn hybrid development, 23 waxy corn hybrids were planted and surveyed in both pericarp thickness and sugar content. Pericarp thickness showed average 50 to $49{\mu}m$ in field and greenhouse. Results like these advanced than previous other hybrids. Also, sugar content in developed waxy corn evaluated as 13.6 to 15.3 brix. Here, we concluded that edible quality of waxy corn depended on combing of two factors. Especially, CNU11H8 hybrid at field and CNU11H-38 at greenhouse were good in both factors. Accordingly, these hybrids will be planted in next time for productivity and area adaptation.

• Korean Journal of Breeding Science
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• v.42 no.3
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• pp.212-217
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• 2010

A new waxy corn hybrid 'Daedukchal 1' was developed from single cross between CNU 504 and CNU 2396 at Chungnam National University in 2007. Inbred CNU 504 used as a seed parent and inbred CNU 2396 as a pollen parent were collected throughout domestic regions. Tasseling date of this hybrid was seven days later than that of check hybrid, 'Chalok 1'. 'Daedukchal 1' was 19.7 cm in ear length and 4.5 cm in ear diameter. On yield trial, ear length of this hybrid was increased 29.7% compared with a check hybrid, 'Chalok 1'. 'Daedukchal 1' had white kernels and good eating quality due to high sugar content and thinner pericarp. The ratio of kernel set length/ear length was similar to 'Chalok 1'. It is moderately resistant to southern leaf blight and northern leaf blight but susceptible to corn borer. The yields of 'Daedukchal 1' in fresh ear weight and in number of fresh ear were 16% and 8%, respectively, higher than those of a check hybrid in regional yield trials for two years. Seed production for this hybrid was better because of the consistency of tasseling dates.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.2
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• pp.185-189
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• 2015

A total of CNU 28 colored hybrids developed at the Chungnam National University were evaluated to identify new cultivars with functionality. These color waxy corn hybrids appeared to have high antioxidant activity. The SOD activity in the developed color waxy corn was high; CNU13H-3, in white hybrid, and CNU13H-44, in yellow hybrid, was 5% and 27% higher than the Yeonnong and Daehakchal Gold 1 of control hybrids, respectively. The DPPH activity in CNU13H-44, of yellow hybrid, and CNU13H-75 of purple hybrid were high as 32.6 mg/g and 40.1 mg/g, respectively. We have already reported that color hybrids have high antioxidant activity. In this study also was same results. On the basis of our findings, these hybrids will be planted in next time to compare their productivity and area adaptation.

• Korean Journal of Breeding Science
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• v.41 no.3
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• pp.279-283
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• 2009

A new yellow waxy corn hybrid "Daehakchal Gold 1" was developed from single cross between Yeongdeok Jaera and Okchen Jaera at Chungnam National University in 2007. Inbred CNU57 derived from Yeongdeok Jaera was used as the seed parent of Daehakchal Gold 1, and inbred CNU 27 derived from Okchen Jaera as the pollen parent. Tasseling date of this hybrid was seven day later than that of check hybrid, Chalok 1. Daehakchal Gold 1 was 19.7cm in ear length and 4.5cm in ear diameter. The yield of Daehakchal Gold 1 and check hybrid in dry matter were 146.5g and 113.9g per plant, respectively. On yield trial, which were increased 29.7% compared with a check hybrid, Chalok 1. Especially, Daehakchal Gold 1 had yellow kernels and good eating quality. The ratio of kernel set length/ear length was similar to Chalok 1. It is moderately resistant to Bioporalis maydis and corn borer. The yields of Daehakchal Gold 1 in fresh ear weight and in number of fresh ear were 16% and 8%, respectively, higher than those of a check hybrid in regional yield trials for three years. Seed production of this hybrid has gone well due to good match during crossing between seed and pollen parents.

• Korean Journal of Organic Agriculture
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• v.19 no.spc
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• pp.6-8
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• 2011

In order to produce the organic foods in accord with international standard, organic seeds should be used in organic farming. This study was conducted to establish the stable production of organic seed of waxy com by examining the growing characteristics, seed yield, and the economy for seed production by organic farming. The optimal sowing timing for organic seed production of waxy com hybrid was within 10 days of the $1^{st}$ of May with yield of 88~90% of conventional seed production. The optimal planting density was 41,600 plants/ha ($80{\times}30$ cm) for organic seed production of waxy com. The weight of 100 seeds and seed productivity increased at the planting ratio of 2:1 mother plant:male plant. Growth and seed production were improved by removing male plant at 7~10 days after silking. Organic fertilizer (mixed oil cake) was applied at a rate of 4~6 Mg/ha before sowing. Black plastic mulching was used for weed control. In addition, sex pheromone trap and bio-control agents were used for safe pest control and low labour cost.

• 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 Breeding Science
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• v.40 no.3
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• pp.250-257
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• 2008

Knowledge of genetic diversity and of the genetic relationships among elite breeding materials has had a significant impact on the improvement of crops. In maize, this information is particularly useful in i) planning crosses for hybrid and line development, ii) in assigning lines to heterotic groups and iii) in plant variety protection. We have used the SSR technique to study the genetic diversity and genetic relationships among 76 Korean waxy corn accessions, representing a diverse collection from throughout Korea. Assessment of genetic diversity among members of this group was conducted using 30 microsatellite markers. Among these 30 microsatellite markers, we identified a total of 127 alleles (with an average of 4.2 and a range of between 2 and 9 alleles per locus). Gene diversity at these 30 microsatellite loci varied from 0.125 to 0.795 with an average of 0.507. The cluster tree generated with the described microsatellite markers recognized two major groups with 36.5% genetic similarity. Group I includes 63 inbred lines, with similarity coefficients of between 0.365 and 0.99. Group II includes 13 inbred lines, with similarity coefficients of between 0.45 and 0.85. The present study indicates that the 30 microsatellite loci chosen for this analysis are effective molecular markers for the assessment of genetic diversity and genetic relationships between Korean waxy corn accessions. Specifically, this study's assessment of genetic diversity and relationships between a set of 76 Korean waxy corn inbred lines will be helpful for such activities as planning crosses for hybrid and line development and association mapping analyses of maize breeding programs in Korea.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.60 no.4
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• pp.470-474
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• 2015

This study was carried out to compare botanical and amylogram characteristics including table quality in waxy corn kernel. The used materials in this experiment were producted and evulated at Corn Breeding Laboratory, Coll. of Agri. & Life Sci., in CNU. In botanical characteristics CNU H09-26 among used hybrids was highest in stem height as 228.5 cm, but that of CNU H09-30 was lowest. Ear height was highest in CNU H09-23 as 78.2 cm, but that of CNU H09-30 was lowest. Ear length among hybrids were also variable as 21.2 cm to 10.8 cm. in amylogram analysis CNU H09-23 hybrid was lowest in pasting temperature, while break down of this hybrid was highest These results appeared highly in table quality. Accordingly we thought that this hybrid will be adapted as a leading variety for edible waxy corn.

• Korean Journal of Breeding Science
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• v.43 no.1
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• pp.62-67
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• 2011

This study was carried out to gain basic informations about amylogram, antioxidant activity function and physicochemical properties for kernel of the newly developed waxy corn hybrids. The used materials were produced in 2008 and cultivated at breeding farm of CNU in 2009. From amylogram analysis, peak and minimum viscosity of the used hybrids were appeared in CNU08H-71 and CNU08H-69 hybrid, respectively. DPPH free radical scavenging effect marked as election donating ability was highly appeared in CNU08H-15 and CNU08H-69 hybrid, while CNU08H-h102 hybrid was the lowest. Hardness of kernel was highly appeared in CNU08H-35 hybrid, and chewiness and gumminess were also the highest in this hybrid, but those of CNU08H-h105 hybrid were the lowest. In these facts, we confirmed that the used hybrids were very different among traits related to amylogram, functions and table qualities. Accordingly, development of the new waxy corn hybrid will be profitable to select and develop as a crossing combination including many excellent traits.

• Korean Journal of Agricultural Science
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• v.27 no.2
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• pp.81-85
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• 2000

In order to find a proper storage temperature and times for vegetable waxy corn, several waxy hybrids used in the study. Among waxy hybrids, stem height and ear length of Daehakchal and Eulrukchal hybrides were higher than Chalok#1 and #2 used as a check, but flowering daus were later about 7 days than check. Sugar content of Daehakchal was not almost changed at $-4^{\circ}C$ and below, whereas it was rapidly decreased at $4^{\circ}C$. Most hybrids with high sugar content were fast converted into starch than lower content hybrid. While moisture contents of waxy hybrids used were almost constant regardless of storage temperature in vegetable com packaged with poly ethylene vinyl. From these results, storage temperature of vegetable waxy corn was recommended at least $-4^{\circ}C$ below. Under the $-10^{\circ}C$ and below, storage period of vegetable waxy corn could prolong 60 days and above because sugar and moisture content of vegetable corn measure at $-10^{\circ}C$ and $-20^{\circ}C$ were almost no changed compared with those of fresh corn measured at harvest.