[Next Breeding] Red Even Without Reflective Film… RDA’s New Apple Variety ‘Manhong’

Every autumn, apple orchards see a string of tasks: laying reflective film, removing leaves, and rotating fruit. That is because apples must develop an even red hue to fetch a proper price. According to the Rural Development Administration’s 2024 Agricultural Income Data Book, labor hours spent on apple coloration management amount to 16.2 hours per 10 ares, accounting for 11.2% of total labor input.

This burden is growing heavier with climate change. As high autumn temperatures last longer, apples with insufficient coloration are more often reaching the market and prices are falling. Kim Min-ju, a researcher at the Apple Research Center of the National Institute of Horticultural and Herbal Science, said, “Coloration in apples originally was not a major problem, but complaints that apples do not color well have increased due to the impact of abnormal weather,” adding, “Consumers choose red apples, so growers lay reflective film or rotate fruit, and all of that costs labor.” The new apple variety ‘Manhong,’ bred by the National Institute of Horticultural and Herbal Science under the Rural Development Administration, completed variety protection registration in 2025 and was introduced through a press release last month. It is a late-maturing variety developed to reduce this coloration burden.

Park Jae-yeol, who grows apples on 25,000 pyeong (about 82,600㎡) in Yeongju, North Gyeongsang Province, has faced the same concern. Park first planted Manhong four years ago for regional adaptation trials, and after observing the results, he planted an additional 400 to 500 trees on his own this spring. “Because there is no coloration problem, it can be grown without laying reflective film,” he said. “That is its greatest advantage.”
Manhong’s biggest characteristic is that it develops an even red color even on the side that receives less sunlight. We interviewed Senior Researcher Kwon Soon-il of the same center, who handled the initial crossbreeding, Researcher Kim Min-ju, who took over the research, and growers who cultivated it in the field to examine its development process, achievements, and remaining challenges.
 

The color of Hongso, the taste of Gamhong… 15 years from crossbreeding to variety protection registration

Manhong is a variety obtained in 2010 by crossing ‘Hongso,’ which colors well on the peel, as the mother parent, with ‘Gamhong,’ known for its excellent taste, as the father parent. It began with awareness of the problem that the domestic late-maturing apple market is concentrated on a single variety. Kim explained, “When varieties are concentrated in one type, there are advantages, but if a problem arises in the industry, growers can suffer a major blow,” adding, “The purpose was to diversify varieties and create an apple that is delicious in late October while also coloring well.”

Each parent variety had shortcomings. Hongso colors well but was not commercialized because of problems with rough skin, while Gamhong tastes good but has an uneven appearance. Among the first-generation (F1) individuals obtained through crossbreeding, Senior Researcher Kwon selected those that did not inherit rough skin, colored well, and were large in size. He said it is “a variety with traits that surpass both its mother and father.”

The selected individual received the line name ‘Wongyoga-81’ in 2016 and underwent regional adaptation trials in several areas. After final selection in 2022, an application for variety protection was filed in 2023, and registration was completed in 2025. Regarding why it took so long, Kwon recalled, “Its size and yield surpassed existing major varieties, but because it had to compete with strong contenders that come out at the same time, we spent a long time considering whether it could survive in the market while carrying weaknesses in taste and storability.”

A large apple averaging 380g with even coloration… coloration work expected to be 20–30% of that required for existing varieties

Manhong is a round, large-fruited apple with an average fruit weight of 380g. Its sugar content is 14.4 Brix and acidity is 0.44%, combining sweetness and tartness, while its flesh firmness is 69.9N, making it firm yet juicy. The harvest period is mid- to late October, with the average maturity date around October 21.

The researchers explained that the difference in coloration is large enough to be visible to the eye. Kwon said, “When observed under the same conditions in similar locations, the degree of red coloration is clearly different.” Although there is not yet data quantitatively comparing labor for coloration management, he predicted, “If the time required for existing varieties is set at 100, we believe only 20 to 30 will be needed.”

Expectations are also high in the field for labor savings. According to Park, one skilled worker lays reflective film over about 900 pyeong (about 3,000㎡) per day. He mainly uses foreign workers, and daily labor costs are 130,000 to 140,000 won for men and 110,000 to 120,000 won for women. Park said, “Since we do not have to lay reflective film, I think labor costs will be reduced,” adding, “Using less film also means less concern about waste.” Although the cultivation area is not yet large enough to calculate the exact scale of savings, he said, “For now, I am satisfied with the color.”

Large fruit also reduces harvest labor. In Park’s orchard last year, some fruit weighed as much as 800g each. “Manhong fills with one apple the weight that would require picking two or three smaller apples,” he explained. “The labor cost for picking and for removing stems is all much lower.” His assessment is that high-yield cultivation is also possible because the harvest volume from the same tree is large. Kim also said, “In Korea, there is strong demand for large, attractive apples for ancestral rites and gifts, so it is competitive in appearance and size.”

Taste can vary each year depending on weather conditions. Kwon said, “When fruit is large, the taste can be bland, but this year there was little rain and plenty of sunlight, so sugar content increased,” adding, “At this year’s quality level, it can hold its own against other varieties that come out in October.” Park also said, “I am satisfied with its taste, sugar content, and texture.”

The researchers explain that cultivation management is not difficult either. Kwon said, “It is not especially weak against any particular disease; it has moderate or higher resistance to most diseases, so there is no problem if it is controlled at the level used for ordinary varieties.” However, fruit anthracnose and leaf brown spot disease may occur in some cases under conventional pest and disease control conditions, so timely control is needed. Park said, “I planted it and worked it exactly the same as other apples, and there were no special problems.” The researchers believe that because tree vigor is moderate, it should not be difficult to train it into a planar tree form suitable for mechanized work.

Demonstrations in 10 major production areas… ‘Willingness to plant in my field’ scores above 4 out of 5

Manhong is currently undergoing field demonstrations in 10 major production areas nationwide. Test orchards of 300 pyeong (about 1,000㎡) have been established at 10 farms in Yanggu, Gimcheon, Yeongju, Uiseong, Pohang, Andong, Gunwi, Geochang, Miryang, and Jangsu, with 10 to 20 trees each of nine varieties, including Manhong, planted to examine regional characteristics. The project began in 2023, the first harvest took place in 2025, and this year is the second year of fruit characteristics surveys. The project will continue until 2032.

Kim said, “We cannot determine the characteristics of a variety based on only one or two years of results,” adding, “This is a project to refine cultivation techniques while observing trends over 10 years.” She added, “When choosing a variety, growers will try to reduce risk and increase profit,” and said, “The demonstration results will help with that judgment.”

Field response has been positive. At a field evaluation meeting for the ‘Manhong’ major production areas held on the 15th of last month at Top Apple Farm in Yeongju, North Gyeongsang Province, representatives of growers in major production areas were asked on a five-point scale whether they were “willing to plant it in my field,” and Manhong received a score of 4 or higher. Other varieties evaluated together scored only 1 to 2 points. Kim said, “Many growers said this year’s fruit was the tastiest, and we see that as the result of the variety’s characteristics emerging more clearly as cultivation techniques have been improved,” while emphasizing, “Results differ depending on the grower’s level of skill.”

The market’s evaluation still remains. Park said frankly, “Consumers are already accustomed to the taste of Fuji, which has been proven, so I also worry about whether it can compete with and beat not only Fuji but also other new varieties.” He also pointed out that the advantage of requiring less labor alone does not guarantee prices. “Other varieties that we planted because they required less labor are also not getting good prices this year,” he said.
He was also calm about price expectations. Park said, “When Fuji is 30,000 won, saying a new variety will fetch 50,000 won is an exaggeration,” adding, “If it is easy to grow, costs less in labor, and tastes decent, that is farm income.” When production increases, he plans to ship through wholesale markets and direct transactions. “I will clearly show the taste to middlemen and tell them that if it tastes good, they can put a high price on it and judge for themselves,” he said.

The ‘harvest timing’ that will decide success or failure… finding the economic maturity stage by region

The issue researchers are paying the most attention to is harvest timing. If Manhong is harvested after passing maturity, oily components from the peel (fruit-skin lipids) seep out, making it sticky to the touch. Consumers dislike this, and it is also disadvantageous for storage at room temperature. Kim said, “At the evaluation meeting, we repeatedly urged growers not to harvest late.”

Kwon explained that physiological maturity and economic maturity must be distinguished. “Manhong’s physiological maturity is in late October, but if it is picked a little early, storability improves and lipid formation is delayed,” he said. “Taking into account even the part where sugar content rises less, we must determine when the economic maturity stage is for each region.” He explained that whether the optimal harvest time should be moved earlier than October 10 or set around October 10 to 15 can only be judged after more regional data is accumulated.

Regional differences are being confirmed in the field. Park harvested around October 20 this year, but there was no stickiness on the peel. “Perhaps because our orchard is at an elevation of 320 to 350 meters, lipids did not appear even when we picked on the 20th,” he said, noting that regional differences may occur.

The shipping timing is also directly linked to price. Park said, “If you pick and ship around October 10, the price is better, but after the 20th, Fuji pours into the market and prices fall.” Conversely, researchers caution against picking too early. Because the color develops early, there are cases of harvesting in September and putting it on the market for Chuseok. Kwon expressed concern, saying, “Putting it on the market before it has developed flavor is a shortcut to shortening the life of the variety.”

Storability is also a matter of interest. The room-temperature (20℃) storage period disclosed by the researchers is about 20 days. Park has placed this year’s harvested Manhong in cold storage. “After putting it in myself, I think it would not deteriorate even if kept until April,” he said. The optimal harvest timing and storage period are tasks that must be refined together through field demonstrations.

Sufficient supply of saplings after 2028… dissemination centered on the south, where coloration is difficult

Saplings will be sold through nursery companies that have received non-exclusive licenses. Sales volume next spring will not be large, but because companies plan to greatly increase grafting next year, researchers believe sufficient quantities can be secured after 2028. Park predicted, “It will take about three years for sapling supply to increase in earnest.”
A plan for dissemination regions has also emerged. Kwon said, “As temperatures rise, one of the factors that lowers apple quality is poor coloration,” adding, “Since northern regions can grow other varieties as well, it would be good to encourage dissemination mainly in southern regions where apple cultivation is difficult because of coloration.” He added, “We will establish a system so that nursery companies can convey the researchers’ cultivation information as much as possible when selling saplings.”
The Apple Research Center is also working to raise the dissemination rate of domestic varieties. The dissemination rate of domestically bred apple varieties rose from 17.5% in 2015 to 21.4% in 2020 and 23.8% in 2025. In April, the Rural Development Administration announced a plan to raise the dissemination rate of domestically bred apple varieties to more than 35% by 2030, reducing dependence on foreign varieties and strengthening the competitiveness of Korea’s apple industry. Kwon said, “To significantly increase the share of domestic varieties, we ultimately have to release varieties in the late-maturing market that satisfy both consumers and growers by offering taste and storability as well.” Kim said, “We are focusing on breeding varieties that match consumer demand.”