• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.51 no.5
• /
• pp.425-431
• /
• 2006

In order to investigate the effects of ethylene on the seed development of three corn types (dent, sweet, and super sweet corns), aminoethoxyvinyl glycine (AVG) and silver thiosulfate (STS) and ethephon (2-chloroethylphosphonic acid, CEPA) were applied either on whole plants or shanks of ears at 9 and 21 days after silking. Ethylene production of developing super sweet corn seeds was much higher than those of sweet and dent corns. The cavity in the endosperm tissues of the super sweet corn started earlier and endosperm was collapsed more severely compared to those of sweet and dent corns. Ethylene production seemed to be related to the death of endosperm cells to form a cavity. Application of AVG and STS reduced ethylene production and delayed cavity formation in endosperm of super sweet corn seeds, while CEPA increased ethylene production and enhanced the time of cavity formation. AVG and STS increased 100-seed weight, while CEPA decreased.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.32 no.1
• /
• pp.86-91
• /
• 1987

Changes in the contents of sugars and soluble solids and flavor rate of cooked kernels of three sweet com hybrids (Great Bell, Danok 1, and Golden Cross Bantam) and a super sweet corn hybrid (Crisp Super Sweet 720) were observed from 15 days after silking (DAS) to 27 or 33 DAS in 1985 and 1986 to determine the optimum harvest time. Sucrose content in all hybrids and fructose and glucose contents of Crisp Super Sweet 720 increased from 15 DAS to 21 or 24 DAS and then decreased. However, in the three sweet corn hybrids both fructose and glucose contents were highest at 15 DAS and then continuously decreased with maturity. At harvest time the major sugar component was sucrose and the highest total sugar content of Crisp Super Sweet 720 was 2-3 times higher than that of three sweet corn hybrids. Soluble solids were continuously increased with maturity in three sweet com varieties, but that of Crisp Super Sweet 720 increased up to 24 DAS, maintained the level through 30 DAS and then decreased. At harvest time soluble solids of three sweet com varieties were much higher than that of Crisp Super Sweet 720. The optimum harvest time seems to be about 27 DAS considering flavor rate and marketing conditions although the total sugar content was lower than those of earlier harvests. Soluble solids but not total sugars were positively correlated with the flavor of cooke6 com harvested at different growth stages in the same variety. Total sugars were not correlated with soluble solids or negatively correlated depending on hybrids.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.33 no.1
• /
• pp.1-5
• /
• 2013

Andaok, a new single cross variety, is a yellow dent maize hybrid (Zea mays L.) developed by the maize breeding team at the National Institute of Crop Science (NICS), RDA in 2011. This hybrid, which has a high yield of grain, was produced by crossing two inbred lines, KS161 and KS162. KS161 is the seed parent and KS162 is the pollen parent of Andaok. Silking date of Andaok is 3 days later than that of the check hybrid, Jangdaok. Plant height of Andaok is longer than that of Jangdaok. Ear numbers per 100 plants of Andaok is more than that of Jangdaok. Ear length of Andaok is shorter than that of Jangdaok. The weight of 100 seeds of Andaok is heavier than that of Jangdaok. It has moderate resistance to southern corn leaf blight (Bipolaris maydis), black streaked dwarf virus (BSDV) and corn borer. It has strong resistance to northern corn leaf blight (Exserohilum turcicum). It has resistance to lodging. Andaok was evaluated for its yield of grain at three locations from 2009 to 2011. The grain yield of Andaok was 7.80 ton/ha. Seed production of Andaok has gone well due to a good match during crossing between the seed parent, KS161, and the pollen parent, KS162, in Yeongwol.

• Korean Journal of Breeding Science
• /
• v.41 no.3
• /
• pp.310-313
• /
• 2009

A single cross, Pyeonganok, is an yellow flint-like maize hybrid (Zea mays L.) developed by the maize breeding team at the National Institute of Crop Science (NICS), RDA in 2008. This hybrid, which has a high yield of dry matter was produced by crossing two inbred lines, KS140 and KS94. KS140 is the seed parent and KS94 is the pollen parent of Pyeonganok. Silking date of Pyeonganok is 3 days later than that of check hybrid, Kwangpyeongok. Stay-green of Pyeonganok is not greatly different with that of Kwangpyeongok. It has resistance to lodging. It has moderately resistance to Bipolaris maydis (southern corn leaf blight), Exserohilum turcicum (northern corn leaf blight), and corn borer but sensitivity to black streaked dwarf virus (BSDV). Pyeonganok was evaluated for the yields of dry matter at four locations from 2006 to 2008. The yields of Pyeonganok in dry matter was 20.84 ton/ha. Seed production of Pyeonganok has gone well due to a good match during crossing between the seed parent, KS140 and the pollen parent, KS94 in Yeongwol.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.28 no.4
• /
• pp.307-314
• /
• 2008

No comprehensive tillage system of corn (Zea mays L.) has been conducted in Korea. Therefore, this experiment was carried to determine soil characteristics, weed and forage production in tillage system of corn. Plot was allotted to one of four treatments in a randomized block design using tillage system. The four treatments were (T1) conventional tillage, plow and rotary till, (T2) rotary till, (T3) disk till, and (T4) no-till system. In soil characteristics before planting and after harvest of corn, pH and organic matter at planting date was higher than at harvest date, however, there were no difference among tillage system. Days from planting to silking of no-till was the longest among tillage system. Lodging resistance of disk and no-till were higher than conventional and rotary till due to its thicken stem diameter. Main weed in corn field are barnyard grass (Echinochloa crusgall), velvetleaf(Abutilon avicennae), crabgrass (Digitatia saguinalis), and redroot pigweed (Amaranthus retroflexus). Weed population was lower in no-till than others tillage system. Dry matter (DM) content and ear percentage of conventional and rotary till were higher than others in corn field. However, DM and total digestible nutrients (TDN) yields of disk and no-till were higher than those of conventional and rotary till. Therefore, disk and no-till are more suitable in corn silage system because of high lodging resistance and forage yield, and low weed population.

• Korean Journal of Breeding Science
• /
• v.50 no.4
• /
• pp.510-515
• /
• 2018

Hwangmichal, a yellow waxy corn hybrid, is a single cross hybrid developed in 2014. This hybrid was created by crossing the seed parent KY30 and pollen parent KY9. Hwangmichal has yellow kernels with a conico-cylindrical ear shape. The days to silking of Hwangmichal were similar to that of Ilmichal, a check hybrid. The ear height ratio of Hwangmichal was 50%, which was lower than that of Ilmichal, and its number of tillers was less than that of Ilmichal. The ear size of Hwangmichal was smaller than that of Ilmichal and the kernel set ratio was 89%. Its sensory evaluation was better than that of Ilmichal. The carotenoid content of Hwangmichal was $32.2{\mu}g/g$, which was much higher than that of Ilmichal. Lodging resistance of Hwangmichal was better than that of Ilmichal. Although the number of fresh ears of Hwangmichal was more than that of Ilmichal, the weight of fresh ears was lower than that of Ilmichal. The flowering period of its parent lines was well matched and seed production was 3:1 at a planting density of parent lines of more than 2:1. It is adaptable to the whole country except for Jeju-do. The plant variety protection right of Hwangmichal was registered in June 2017, and its grant number is 6728.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.17 no.3
• /
• pp.261-269
• /
• 2015

The purpose of this research is to identify the significance of climate factors related to the significance of change of dry matter yield (DMY) of whole crop maize (WCM) by year through the exploratory data analysis. The data (124 varieties; n=993 in 7 provinces) was prepared after deletion and modification of the insufficient and repetitive data from the results (124 varieties; n=1027 in 7 provinces) of import adaptation experiment done by National Agricultural Cooperation Federation. WCM was classified into early-maturity (25 varieties, n=200), mid-maturity (40 varieties, n=409), late-maturity (27 varieties, n=234) and others (32 varieties, n=150) based on relative maturity and days to silking. For determining climate factors, 6 weather variables were generated using weather data. For detecting DMY and climate factors, SPSS21.0 was used for operating descriptive statistics and Shapiro-Wilk test. Mean DMY by year was classified into upper and lower groups, and a statistically significant difference in DMY was found between two groups (p<0.05). To find the reasons of significant difference between two groups, after statistics analysis of the climate variables, it was found that Seeding-Harvesting Accumulated Growing Degree Days (SHAGDD), Seeding-Harvesting Precipitation (SHP) and Seeding-Harvesting Hour of sunshine (SHH) were significantly different between two groups (p<0.05), whereas Seeding-Harvesting number of Days with Precipitation (SHDP) had no significant effects on DMY (p>0.05). These results indicate that the SHAGDD, SHP and SHH are related to DMY of WCM, but the comparison of R2 among three variables (SHAGDD, SHP and SHH) couldn't be obtained which is needed to be done by regression analysis as well as the prediction model of DMY in the future study.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.65 no.2
• /
• pp.93-103
• /
• 2020

The average growth day of 11 maize varieties from planting to silking in the first cropping (FC) was 89.5 days and in the second cropping (SC) was 46.7 days, which was 43 days faster than in the FC. The average 100-kernel weight (100 KW) in the FC was 28.4 g and 18.3 g in the SC, which was approximately 36.4% lower than that in the FC. The average crude oil content of FC was 3.97% and SC was 3.08%, which was about 0.89% lower than that of FC. The composition of stearic and oleic acid was significantly higher in FC, whereas palmitic and linoleic acid were higher in SC; however, linolenic acid was not statistically different between the two crops. The crude oil content was negatively correlated with linoleic acid (FC -0.264^ns, SC -0.504**) and positively correlated with linolenic acid (0.526**). Unsaturated fatty acid (USFA) composition showed a significant difference between FC (83.48%) and SC (82.96%). Total phytosterol content was 598.3 mg/100 g and 701.9 mg/100 g in FC and SC, respectively, and showed significant difference by planting dates. The β-sitosterol content showed no statistical difference between the planting dates, but campesterol and stigmasterol were significantly higher in SC than in FC. Therefore, it was considered that the temperature condition during the ripening period affects the 100 KW of maize, and this leads to the variation in phytosterol content. However, among phytosterols, β-sitosterol was relatively little affected by the planting dates. USFA composition showed a significantly negative correlation with phytosterol content. Considering the results, the relatively high phytosterol content in SC was mainly because of the delay in progress of starch accumulation as daily air temperature decreased from the middle of the ripening period, whereas progress of phytosterol accumulation in the maize kernel was considered relatively faster than that of starch accumulation.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.61 no.4
• /
• pp.277-282
• /
• 2016

The consumption of waxy corn is steadily increasing in Korea. Waxy corn is harvested before it reaches full maturity and consumed immediately or follwing cold storage. Glutinous and sweet kernels are preferred due to their high palatability. The kernel properties can change rapidly following harvest, and, therefore, optimal conditions to maintain the kernel quality of corn should be identified. In addition, the timing of harvest of waxy corn ear should be also determined for optimal marketable corn production. From 10 days after silking (DAS) to25 DAS. fresh ear weight and single kernel weight rapidly increased from 78.3 g and 1.13 g, respectively, to 224.9 and 3.61 g, respectively. However, by 30 DAS both fresh and single kernel weight decreased by 10.6% and 6.1%, respectively. Kernel hardness significantly increased up to 25 DAS, and a further slight increase in kernel hardness was observed at 30 DAS. Total sugar content in kernel decreased from 12.5% at 10 DAS to 3.5% at 35 DAS, which was the result of the conversion of sugars to starch during ear development. Crude protein content in kernel did not vary significantly in comparison to kernel hardness. During storage of ear, kernel hardness increased from $726g\;cm^{-2}$ at harvest to $1894g\;cm^{-2}$ following 28 days of storage at a low temperature ($0^{\circ}C$). Kernel hardness increased 2.5 fold from 15 DAS to 30 DAS. Soluble protein level in kernel increased until 10 DAS, following which a slight decrease was observed. The soluble protein content decreased from 1.85% at 5 DAS to 1.45% at 35 DAS. Total sugar content in kernel decreased regardless of storage temperature; however, the rate of reduction was lower at $0^{\circ}C$ than that observed following storage at $4^{\circ}C$ and $10^{\circ}C$. The rate of reduction in kernel moisture content was also lower at $0^{\circ}C$ than that observed at $4^{\circ}C$ and $10^{\circ}C$.

• Journal of The Korean Society of Grassland and Forage Science
• /
• v.29 no.3
• /
• pp.179-186
• /
• 2009

This study was conducted to evaluate yield and forage quality of domestic silage corn hybrids at different planting dates. Days to silking of Suwon169 and P3394 were 62 days, respectively, the shortest among corn hybrids and Gangdaok was the longest. Cheonganok was more resistant to lodging than other hybrids. Kwangpyeongok and Gangdaok were more excellent to stay-green than other hybrids. Ear ratios to total dry matter of other domestic hybrids except Gangdaok were similar with those of DK697 and P3394. Ear ratios to total dry matter were similar in planting dates, May 3 and May 21 with 46% and 45% but June 11, low with 41%. Fresh yield of Gangdaok was the highest of all hybrids and other hybrids except Gangdaok were similar. Dry matter (DM) yields of domestic hybrids except Cheonganok were similar to those of DK697 and P3394. Total digestible nutrients (TDN) yields of domestic hybrids were no significant difference compared with those of DK697 and P3394. Fresh yield, DM yield and TDN yield of all hybrids were similar in planting dates, May 3 and May 21 but those of all hybrids were reduced in planting date, June 11 compared with May 3 and May 21. All hybrids were no significant difference in acid detergent fiber (ADF) which had values ranging from $44.2{\sim}46.2%$. All hybrids were no significant difference in neutral detergent fiber (NDF) which had values ranging from $58.1{\sim}59.9%$. There were no significant differences in ADF and NDF according to planting dates. Relative feed value (RFV) of P3394 was the lowest of all hybrids. Other hybrids except P3394 had values ranging from $84.1{\sim}85.0$ and was no significant difference in RFV. It is concluded that domestic hybrids tested in this study have high forage quality as well as high production similar to those of imported corn hybrids.