Blue honeysuckle (Lonicera caerulea L.), a member of Caprifoliaceae family, is a deciduous shrub that is also known as “Haskap” or “honeyberry.” Because of its extra-early ripening, high content of bioactive metabolites in fruit, and outstanding frost resistance of buds and flowers, blue honeysuckle has become a novel cash crop in continental climate regions (Plekhanova 2000). In the 21st century, its cultivation has undergone rapid expansion, not only in eastern Europe and northern America, but also in Northeast Asia, especially in Hokkaido, Japan, and the northeastern part of China. In the past 20 years, there were no cultivars of blue honeysuckle reported in China, and most of its production relied heavily on wild collection and transplantation of local wild blue honeysuckle (L. caerulea var. edulis). However, wild blue honeysuckle has the weaknesses of easy fruit abscission, low yield, obvious bitterness, severely tart taste, and low fruit firmness (Huo et al., 2005). ‘Lanjingling’ [China National Plant Variety Protection (CNPVP) 20200389] and ‘Wulan’ (CNPVP 20200390) are the first two nationally registered blue honeysuckle cultivars developed by the Northeast Agricultural University (NEAU). ‘Lanjingling’ is characterized by relatively high fruit firmness, large fruit size, and negligible bitterness; thus, it is suitable for the fresh-fruit market. ‘Wulan’ is characterized by high yield, excellent flavor, and strong aroma, with great commercial value in the food, medical, and cosmetic fields.
Origin
‘Lanjingling’ and ‘Wulan’ are derived from a cross between ‘Berel’ and ‘Blue bird’ (pedigree shown in Fig. 1). The female parent ‘Berel’ is derived from a cross between the excellent line ‘12-19’ (L. caerulea subsp. altaica) and mixed pollen of ‘Blue spindle’, ‘Blue bird’, and ‘Azure’. These three cultivars are open-pollinated offspring of a wild L. caerulea subsp. kamtschatica (Boyarskikh 2017; Hummer 2006; Plekhanova 2000). In 2003, author J. Huo introduced ‘Berel’ and ‘Blue bird’ to the NEAU (Harbin, China) from M.A. Lisavenko Scientific Research Institute of Horticulture (Novosibirsk, Russia) of the “948” project (project titled “Introduction of International Advanced Agricultural Science and Technology” funded by the Ministry of Agriculture of the People’s Republic of China). In 2005, Huo pollinated ‘Berel’ with the pollen of ‘Blue bird’ and obtained 208 seeds. The seeds were sown in the Gardening Station of the NEAU in Apr 2006, and the 90 grown seedlings were labeled Line (L)1 to L90. Field selection was conducted during their fruit-bearing period from 2007 to 2010. Of the 90 seedlings, L4 and L52 exhibited outstanding performance. L4 displayed a large fruit size and high berry firmness, and L52 showed a high yield and sweetness. From 2011 to 2013, these two lines (L4 and L52) were propagated systematically by cutting, and the stability of their specific traits was verified by the method proposed by the Forest Variety Certification Committee of Heilongjiang Province (2011). From 2014 to 2019, L4 and L52, as a new type of cash crop, passed the climate test at Jiagedaqi (lat. 51.6°N, long. 122.9°E), Harbin (lat. 45.8°N, long. 126.6°E), and Mudanjiang (lat. 44.6°N, long. 129.1°E) following standard (Heilongjiang Management Station of Tree Seed and Seedling, 2001) under the supervision of the Heilongjiang Forestry and Grassland Administration. These three test sites correspond to United States Department of Agriculture (USDA) hardiness zone 3a, 3b, and 4a respectively. In Dec 2020, L4 and L52 were issued a Plant Cultivar Right Certificate by the National Forestry and Prairie Bureau, with the register names ‘Lanjingling’ (‘蓝精灵’, CNPVP 20200389) and ‘Wulan’ (‘乌蓝’, CNPVP 20200390), which mean “blue genius” and “raven blue” in Chinese, respectively.
Pedigree of ‘Lanjingling’ and ‘Wulan’ blue honeysuckles.
Citation: HortScience 57, 9; 10.21273/HORTSCI16674-22
Pedigree of ‘Lanjingling’ and ‘Wulan’ blue honeysuckles.
Citation: HortScience 57, 9; 10.21273/HORTSCI16674-22
Pedigree of ‘Lanjingling’ and ‘Wulan’ blue honeysuckles.
Citation: HortScience 57, 9; 10.21273/HORTSCI16674-22
Description
The two cultivar plants are half-upright (height of 1.5–1.8 m for a 5-year-old plant) with vigorous growth, dark-green foliage, and strong branches. ‘Lanjingling’ has a wider canopy (an approximate one-meter diameter for a 5-year-old plant) than ‘Wulan’ (∼0.7 m). In terms of picking, ‘Lanjingling’ fruit holds tighter onto the carpopodium than ‘Wulan’; thus, the latter can be picked easily. The berry of ‘Lanjingling’ is bottle-shaped or is an elongated oval with the entire “belly-button bottom” deeply sunk. The berry skin is thick, and it is covered with thick wax, which is deep blue (Fig. 2). The berry has a firm texture and modest aroma; tastes sour and sweet, with negligible bitterness. The berry of ‘Wulan’ is oval-shaped with a tiny, sunk belly-button bottom, and its berry skin and wax are of moderate thickness, and are dark blue (Fig. 3). The berry has a juicy texture and intense aroma; it tastes sweet, with a slight bitterness. The two cultivars exhibit good adaptability to the plains and piedmont regions in Heilongjiang Province, China (accumulated temperature above 0 °C, 1300–1500 °C; annual precipitation, 450–650 mm; soil pH, 6–8), with no necessity for cold-proof management or soil amelioration, such as root covering in winter or soil acidity improvement. No notable diseases or pests that commonly do harm to the northern highbush blueberry, raspberry, and blackcurrant have been observed in the vicinity of the test plots. Propagation is accomplished easily by using either softwood cuttings, hardwood cuttings, or tissue culture, with the softwood cutting recommended most frequently. As verified in the cultivar certification, ‘Lanjingling’, ‘Wulan’, and ‘Berel’ can serve as the pollinizer for each other in commercial cultivation, with an empirically optimal planting proportion of 3:1:1 (any one of the three cultivars could be the dominant one). ‘Blue bird’, ‘Fire opal’, and ‘Iliata’ are also recommended as the pollinizer for ‘Lanjingling’ and ‘Wulan’.
Inflorescence (A), fruitlet (B), and mature berry (C) of ‘Lanjingling’ blue honeysuckle.
Citation: HortScience 57, 9; 10.21273/HORTSCI16674-22
Inflorescence (A), fruitlet (B), and mature berry (C) of ‘Lanjingling’ blue honeysuckle.
Citation: HortScience 57, 9; 10.21273/HORTSCI16674-22
Inflorescence (A), fruitlet (B), and mature berry (C) of ‘Lanjingling’ blue honeysuckle.
Citation: HortScience 57, 9; 10.21273/HORTSCI16674-22
Inflorescence (A), fruitlet (B), and mature berry (C) of ‘Wulan’ blue honeysuckle.
Citation: HortScience 57, 9; 10.21273/HORTSCI16674-22
Inflorescence (A), fruitlet (B), and mature berry (C) of ‘Wulan’ blue honeysuckle.
Citation: HortScience 57, 9; 10.21273/HORTSCI16674-22
Inflorescence (A), fruitlet (B), and mature berry (C) of ‘Wulan’ blue honeysuckle.
Citation: HortScience 57, 9; 10.21273/HORTSCI16674-22
Table 1 presents the basic phenological period of ‘Lanjingling’, ‘Wulan’, and wild blue honeysuckle (L. caerulea var. edulis) at the Gardening Station of the NEAU (lat. 45.74°N, long. 126.72°E), during 2017–19. The anthesis of the two cultivars begins at the last week of April with partial overlapping (‘Lanjingling’ ∼2 d earlier), and the anthesis of these two cultivars is earlier than that of wild blue honeysuckle, indicating that these two cultivars are suitable to serve as the mutual pollinizer. The berry of the two cultivars develops fast, with the development period lasting approximately six to eight weeks. The estimated ripening period (75% ripe berry) of ‘Lanjingling’ and ‘Wulan’ ranged from 9 Jun to 24 Jun and from 12 Jun to 27 Jun, respectively, with an overlap of approximately two weeks, thus making joint harvest of the two cultivars possible.
Phenology period and yield of ‘Lanjingling’, ‘Wulan’, and wild blue honeysuckle (Lonicera caerulea var. edulis).
From 2017 to 2019, the yield evaluation of the two cultivars at the Gardening Station of the NEAU was conducted with 30 plants from each variety under a cultivation density of 3850 seedlings/ha. The soil type of test plots was Chinese mollisols and the climate type belonged to USDA zone 3b. No special fertilization was conducted, and sprinkling irrigation was applied for 1 h/d only when the daily maximum temperature was more than 30 °C. The average yield of 5-, 6-, and 7-year-old plants of ‘Lanjingling’ was 2.02, 2.45, and 3.02 kg/tree, respectively, whereas that of ‘Wulan’ was 1.94, 2.52, and 3.37 kg/tree, respectively. The average yield of three types of plants (5-, 6-, and 7-year-old plants) of ‘Lanjingling’ (2.50 kg/tree) and ‘Wulan’ (2.61 kg/tree) was 159.2% and 166.3% greater than that of wild blue honeysuckle (0.98 kg/tree). For 7-year-old plants, ‘Wulan’ showed a greater long-term yield potential (mean yield, 3.37 kg/tree; maximum yield, 4.4 kg/tree) than ‘Lanjingling’ (average yield, 3.02 kg/tree; maximum yield, 4.1 kg/tree). At a cultivation density of 3000 to 4000 seedlings/ha, cutting seedlings of ‘Lanjingling’ and ‘Wulan’ bear berries for the first time at 2 years; they reach a relatively stable yield at 4 years, and have a yield of more than 2 kg of berries/tree at 5 years. The yield performance of the two cultivars in the long term (> 10 years) remains to be investigated further.
The berry traits are presented in Table 2. The average berry size of ‘Lanjingling’ was large (2.46 × 1.01 cm), with an average weight of 1.39 g/berry and a maximum weight of 2.04 g, whereas the average berry size of ‘Wulan’ was medium (1.72 × 0.99 cm), with an average weight of 1.48 g and a maximum weight of 2.33 g. Berry firmness was measured using a digital fruit sclerometer (GY-4; HandPi Instruments Co., Ltd., Yueqing, China). Both ‘Lanjingling’ (2.78 N) and ‘Wulan’ (1.78 N) showed greater berry firmness than wild blue honeysuckle (1.38 N). The firmness of ‘Lanjingling’ (2.78 N) was close to the medium firmness of northern highbush blueberry (∼3N) (Xu et al., 2022). Negligible bitterness, large fruit size, and novel appearance indicated the superior potential of ‘Lanjingling’ in the fresh market. Total soluble solids (TSS) and titratable acidity (TA) were determined by using a pocket Brix-acidity meter (PAL-BX|ACID F5; Atago Co., LTD., Tokyo, Japan). Both the two cultivars showed a greater TSS and a lower TA than wild blue honeysuckle. Among the three tested materials (‘Lanjingling’, ‘Wulan’, and wild blue honeysuckle), ‘Wulan’ showed an excellent sweetness, with the greatest TSS (17.68°Brix) and the lowest TA (1.33%). These fine qualities in combination with a high yield indicate an excellent value of ‘Wulan’ for the food industry.
Berry quality of ‘Lanjingling’, ‘Wulan’, and wild blue honeysuckle (Lonicera caerulea var. edulis).
Taken together, these two cultivars are desirable substitutes for the wild blue honeysuckle in northeastern China, with great commercial value in fruit markets in China, and they might be candidate cultivars or breeding materials in other berry-producing areas in the world.
Availability
‘Lanjingling’ and ‘Wulan’ were certified by the National Forestry and Prairie Bureau in Dec 2020 with certificate no. 20200389 and no. 20200390, respectively. These two cultivars are owned by the NEAU, Harbin City, China. The propagation rights of these two cultivars were granted to Senmeiyuan Biotechnology Co., Ltd., Harbin. Growers and researchers may request propagules by contacting the corresponding author (junweihuo@aliyun.com). These corresponding genetic materials have been deposited at the Gardening Station of the NEAU and are available for research purposes such as the development of new cultivars.
Literature Cited
Boyarskikh, I. 2017 Features of Lonicera caerulea L. reproductive biology Agric. Biol. 52 1 200 210 https://doi.org/10.15389/agrobiology.2017.1.200eng
Forest Variety Certification Committee of Heilongjiang Province 2011 Method: examination and approval of tree varieties Heilongjiang Forestry and Grassland Bureau
Heilongjiang Management Station of Tree Seed and Seedling 2001 Heilongjiang Provincial Standard: Certification of tree varieties (DB23/T 175-2001) Heilongjiang Provincial Bureau of Quality and Technical Supervision
Hummer, K.E. 2006 Blue honeysuckle: A new berry crop for North America J. Am. Pomol. Soc. 60 1 3 8
Huo, J., Yang, G., Sui, W. & Yu, Z. 2005 Review of study on germplasm resources of blue honeysuckle (Lonicera caerulea L.) Yuan Yi Xue Bao 32 159 164
Plekhanova, M.N. 2000 Blue honeysuckle (Lonicera caerulea L.): A new commercial berry crop for temperate climate: Genetic resources and breeding Acta Hortic. 538 159 164 https://doi.org/10.17660/actahortic.2000.538.25
Xu, G., Qi, A. & Wang, H. 2022 ‘Yumeilan’ northern highbush blueberry HortScience 57 506 507 https://doi.org/10.21273/hortsci16298-21
