What are the main strawberry varieties selected in South Korea?

According to the statistics of the Food and Agriculture Organization of the United Nations, in 2019, the total planting area of strawberries in Korea is 6212hm2, the total output is 193000 tons, and the export volume is 5259 tons. The scale of Korean strawberry industry ranks third in Asia and seventh in the world. Before 2000, most of the strawberry varieties cultivated in South Korea were Japanese varieties such as Fengxiang and Zhang Ji. According to Japanese Agricultural News, more than 90% of Korean strawberry varieties were selected from unauthorized Japanese varieties as parents or original parents. Japanese varieties such as Tochiotome, Red Pearl and Akihime were introduced into South Korea without permission. Xuexiang (Seolhyang), Mei Xiang (Maehyang) and so on were selected as parents. Japan's Ministry of Agriculture, Forestry and Fisheries estimates that only South Korean strawberries' infringement in the export market caused about 22 billion yen (1.3 billion yuan) in losses to Japan from 2012 to 2017. Since 2000, excellent varieties have been selected and promoted in South Korea. Xuexiang has become the largest main variety in South Korea, and the popularization rate of Korean domestic varieties is more than 95% in 2019. In 2019, the export value of Korean strawberries was 52.6 million US dollars, three times that of 2009. Korean strawberries occupy the forefront of the market share in Singapore, Malaysia, Hong Kong, Vietnam and Thailand, seizing the export position of Japanese strawberries. According to international norms, new plant varieties need to apply for new variety protection rights within 4 years after listing, and South Korea began to open applications for new strawberry variety protection rights in 2012. Therefore, in a strict sense, there are no legal obstacles to using earlier varieties as parents for new variety breeding in South Korea. Korean strawberry breeding has made remarkable achievements in the past 10 years, and all aspects quickly catch up with Japan, which has important reference significance for the breeding of new strawberry varieties and the development of strawberry industry in China. The main strawberry varieties selected in Korea are introduced as follows.

# short-day varieties #

Xuexiang (Seolhyang)

It was cultivated by Zhongnan Institute of Agricultural Technology in 2005. It has large fruit, high yield, easy to grow, good taste, but low hardness. The hybrid combination is Zhang Ji × Hong Pearl (Lu Bao), the fruit shape is short conical, and the average weight of single fruit is 21g. Flower bud differentiation is slower than Mei Xiang and Zhang Ji, and slightly faster than red pearl. It is suitable for promoting cultivation. If it is planted in the first and middle of September, it can be harvested in late November. It is relatively easy to raise seedlings, and its resistance to powdery mildew is higher than that of Zhang Ji, so it is suitable for green production and is the largest main variety in Korea. Xuexiang pulp is tighter than Zhang Ji, chewing taste is good, deformed fruit and sunken fruit are less, the fruit is uniform, sugar content is 10%-11%, low acidity in winter, more juice and refreshing. The first inflorescence No. 1 fruit is a large fruit with a weight of more than 60g, and hollow fruit will occur. Attention should be paid to the control of storage and transportation in high temperature period, which is used for export in low temperature period in some areas.

Mei Xiang (Maehyang)

It was cultivated by Zhongnan Institute of Agricultural Technology in 2001. It has a high rate of abnormal fruit in the low temperature period, but has a good taste and is resistant to storage and transportation, so it is the main export variety of strawberry in Korea. The hybrid combination is Yi female × Zhang Ji, the fruit shape is a long cone with narrow shoulder, and the average weight of single fruit is 15g. Flower bud differentiation is earlier than red pearl, which is suitable for promoting cultivation. If it is planted in early September, it can be harvested in late November. Due to poor resistance to diseases and insect pests, attention should be paid to the prevention and control of anthracnose in seedling stage and powdery mildew and gray mold in harvest period. Sensitive to environmental impact, the fruit will be temporarily interrupted when high temperature or dry, the incidence of abnormal fruit is higher in low temperature period (5 ℃), and the pollen is less than other varieties. It is worth noting that the sugar content, firmness and coloring ratio of plum fragrance fruit will increase during low temperature storage, so it is very suitable for export.

Gold wire (Kuemsil)

It was cultivated by Qingnan Institute of Agricultural Technology in 2016 to promote the cultivation of medium and large fruit varieties with high sugar content, high hardness and good flavor (with peach flavor). The hybrid combination is Mei Xiang × Xue Xiang, the fruit shape is short conical, and the average weight of single fruit is 20.4g. The flower bud differentiation is one week earlier than that of Mei Xiang, and the number of flower spikes is about 15, which is as vigorous as Xuexiang, but it is not a high-yield variety, so it is suitable for promoting cultivation. If planted in early September, it can be harvested in early November. Because of the flowering characteristics such as short inflorescence and low pollen viability in winter, the possibility of abnormal fruit is high, so it is more advantageous to plant in southern South Korea. The shape of the fruit is conical in spring and autumn and may become shorter if the low temperature persists in winter. Less than 60% of the coloring is no longer colored after harvest (unlike plum incense) and is being tested for export.

Ali Xiang (Arihyang)

In 2017, it was cultivated by the National Academy of Horticulture of the Korean Rural Revitalization Agency, which is used to promote the cultivation of large fruit varieties with high firmness and uniform fruit size. The hybrid combination is Yi female × Xuexiang, with an average single fruit weight of 24g. The flower bud differentiation was 2-3 days earlier than that of Xuexiang, and the early continuous flower formation was good, with an average of 10.5 flowers in the main inflorescence, which could reduce the operation of flower thinning and fruit thinning. It is suitable for promoting cultivation, if it is planted in the middle of September, it will set fruit around December. The resistance to powdery mildew, gray mold and Fusarium wilt was weaker than that of Xuexiang, but the resistance to blight was slightly stronger. The proportion of deformed fruit in the No. 1 fruit of each inflorescence was high, and the proportion of deformed fruit increased at low temperature. The fruit quality is good, but the fruit coloring is fast, at the same time, it should be noted that the sugar content will also increase in the mature stage (coloring more than 90%). When the fruit is overripe, the pericarp becomes black and red. It is being tested for export in Zhongnan, Hongcheng, Yonggui and other places.

Christmas Red (Ssanta)

In 2006, it was cultivated by Xingzhou melons and vegetables Research Institute of Qingbei Agricultural Technology Institute, which is used to promote the cultivation of large fruit varieties with good taste, high hardness and resistance to storage and transportation. The hybrid combination is Mei Xiang × Xuexiang, with an average single fruit weight of 23g. It was planted in the middle of September (greenhouse cultivation), and the harvest time was about one week earlier than Xuexiang. Because of its high initial yield and quality, it is suitable to increase the income of farmers and has been used for export.

Berry Star (Berrystar)

In 2010, it was cultivated by Xingzhou muskmelon and vegetable Research Institute of Qingbei Agricultural Technology Institute, which is used to promote the cultivation of medium and large fruit varieties with high hardness and no hollow fruit. The hybrid combination is Christmas Red × 07-Smur28, and the average weight of single fruit is 21g. It is suitable for promoting cultivation, if planted in early September (greenhouse cultivation) and harvested from December to January of the following year. It is resistant to anthracnose and powdery mildew, easy to plant and manage, and has been used for export.

Bamboo incense (Jukhyang)

Cultivated in 2012 by the Agricultural Technology Center of Tanyang County, South China, it is a semi-facilitative medium-and large-sized fruit variety with high sugar content and hardness and less abnormal fruit. The hybrid combination is Mei Xiang × Hong Pearl, and the average weight of single fruit is 17.2 g. It has strong resistance to powdery mildew, strong stolon occurrence and growth, good continuous fruiting performance, easy flower and leaf picking operation, easy planting management, and has been used for export.

King (Kingsberry)

It was cultivated in 2016 by Zhongnan Institute of Agricultural Technology on Mountain Strawberry Experimental ground, which is used to promote the cultivation of extra-large fruit varieties with good taste, rich fruit juice and light peach flavor. The hybrid combination is Zhang Ji × NS001309, and the average weight of single fruit is 30g. Planted in the first and middle of September, in order to promote coloring in the low temperature period, the night temperature managed was 2 / 3 ℃ lower than that of Xuexiang. The resistance to powdery mildew is weak, the resistance to anthracnose is moderate, and some of them are used for export.

# Neutral varieties #

Rivers (Gangha)

Cultivated by Korea Plateau Agricultural Research Institute in 2008, it has strong ability to form flowers continuously and can adapt to high temperature and long sunshine environment. In 2004, the parent was Samahberi × Elan,2006- 2007 regional test, the plant grew medium, the fruit was oval, the average single fruit weight was 12.0g, the fruit was red, the soluble solids content was 11.7%, the sugar content was high, the acidity was low, the sugar acid ratio was 18.9, the hardness was low, and it was resistant to powdery mildew, anthracnose and Fusarium wilt.

Rehe (Yeolha)

Cultivated by Korea Plateau Agricultural Research Institute in 2013, it has a strong ability to form flowers continuously and can adapt to high temperature and long sunshine environment. In 2008, the parent was Goha × Elsinyo,2010- 2012 regional test, the plant grew strongly, the fruit was conical, the average fruit weight was 12.1g, the fruit was pink, the soluble solids content was 8.6%, the fruit firmness was 37.7g/mm2, the average yield was 117% higher than Flamenco, and was resistant to Fusarium wilt.

Drum (Goseul)

Cultivated by Korea Plateau Agricultural Research Institute in 2016, it has a strong ability to form flowers continuously and can adapt to high temperature and long sunshine environment. In 2012, the parent was Arbi × Xuexiang. In the regional test from 2015 to 2016, the plant grew moderately, with round leaves, 1.5 times higher inflorescence number than the red pearl, average fruit weight 25.9 g, soluble solids content 12.9%, high sugar content, sugar / acid ratio 18.9, high fruit firmness, 31.6g/mm2.

Long River (Jangha)

Cultivated by Korea Plateau Agricultural Research Institute in 2014, it has strong ability to form flowers continuously and can adapt to high temperature and long sunshine environment. In 2008, the parents were selected by Goha × Elsinore,2010- in 2012. in the regional test from 2013 to 2014, the plant grew moderately, the fruit was conical, the average single fruit weight was 11.7g, the soluble solids content was 9.6%, and the fruit firmness was 38.9g/mm2.

# seed breeding variety #

Seeberry, a F1 hybrid variety of short-day strawberries, was bred by South Korea protected Horticulture Experimental Station. It was reviewed by the crop breeding Committee of Zhenxing Hall in South Korea in 2013 and named Xibeli. It is the first seed propagation variety in South Korea. The male parent is Wongyo 3115 with high hardness, and the female parent is Wongyo 3116 with high yield and fruit shape, which is the multiple inbred progeny of Hongyan and Toyonoka, respectively. Siberian single inflorescence has 12-15 flowers, strong plant growth, conical fruit, average fruit weight 15-16g, bright red color, good taste, soluble solids content 9.7%, titratable acid content 0.6%, hardness 19.0g/mm2, higher than Zhang Ji (13.1g/mm2), resistant to anthracnose, but susceptible to powdery mildew, aphids and red spiders. Sibelium is a seed breeding variety, and the seedling stage may have an effect on the quality and yield of strawberry seedlings. Therefore, the seedling should be grown at least 120 days after sowing, that is, the root neck thickness should be more than 10mm. Only by using these fine seedlings can the characteristics of Siberian varieties be reflected. According to the climatic characteristics of South Korea, the best sowing time is the end of February and the beginning of March. The germination rate of seeds collected in that year is more than 90%, but long-term preservation tends to reduce the germination rate, so it must be refrigerated in order to maximize the germination rate. When raising seedlings by sowing seeds, there is a phenomenon that strawberries blossom when they are not growing enough. pick flowers at this time to prevent weakness. Some problems such as slight decrease of fruit firmness and lighter fruit color will occur in spring, so shading treatment is needed to reduce the environmental temperature of fruit development.

Source: this article is extracted from Chinese Fruit trees, No. 8, 2021, introduction of Strawberry breeding in Korea (Sun Jian, Li Shuangtao, Chang Linlin, Dong Jing, Zhong Chuanfei, Sun Rui, Gao Yongshun, Liu Huabo, Wang Guixia, Zhang Yuntao).