The perennial herb Iris sanguinea, which belongs to the Iridaceae family, exhibits wide distribution across Russia, China, Korea, Japan, and other countries. Renowned for its exquisite butterfly-like shape and captivating blue–violet flowers, this rare alpine ornamental plant has immense potential for diverse applications.
Flower color is a crucial ornamental characteristic of ornamental plants. I. sanguinea has rare blue–violet flowers in the plant world, and its forma I. sanguinea f. albiflora has white flowers, thus creating a good material foundation for flower color breeding of I. sanguinea. It has been reported that there are many cultivars of I. sanguinea with various flower colors, such as Forest Fairy (Kuwantai et al. 2018), Zi Meiren (Chen et al. 2019), Flower Angel (Fan et al. 2021), NEFU-1 (Qi et al. 2020), Donglin Zi (Yang et al. 2022), and others. Unique flower colors are often attractive; therefore, flower color breeding has always been an important direction in the breeding of I. sanguinea. In 2017, a new cultivar of I. sanguinea, Donglin Yixia, which has an outer perianth that is purple [Royal Horticultural Society (RHS) N81A] and an inner perianth that is light purple (RHS N81D)], was discovered.
Origin
The seeds of I. sanguinea and I. sanguinea f. albiflora were introduced by Shenyang Botanical Garden in 2003, and they were subsequently planted in the nursery of Maoershan Experimental Forest Farm of Northeast Forestry University during the spring. The seeds of open-pollinated I. sanguinea and I. sanguinea f. albiflora were collected in 2011, and they were sown in the same nursery in Spring 2012. In 2017, an excellent and unique single F1 plant with two colors was observed. The plant was expanded from 2017 to 2020 using the ramet method to establish a clonal population. The plant grew healthily, and its fine characteristics, such as flower color, remained consistent and stable. It was named ‘Donglin Yixia’ and registered with the American Iris Association in 2022 (registration no. 22-0585).
Description
‘Donglin Yixia’ and its parents, I. sanguinea and I. sanguinea f. albiflora, which were planted in the nursery of the Northeast Forestry University in Harbin, adopted a completely randomized block design. Three repeated random blocks were made, and each contained 20 plants of I. sanguinea, I. sanguinea f. albiflora, and ‘Donglin Yixia’. In 2020, 10 plants were randomly selected from each block, with a total of 30 plants for phenotypic observation and comparison. These phenotypic records included plant height, leaf length, leaf width, leaf length/width, bract length, bract width, bract length/width, flower diameter, length and width of the inner perianth, inner perianth length/inner perianth width, length and width of the outer perianth, outer perianth length/outer perianth width, flower color, flowering period, and fruit period. The color of the flowers was recorded according to the color chart of the Royal Horticultural Society (2007), and statistical analyses were performed using SPSS (version 24.0; SPSS Inc., Chicago, IL, USA). The statistical results are shown in Table 1.
‘Donglin Yixia’ and the morphological characteristics of its parents.
‘Donglin Yixia’ was selected from the open pollinated progeny of I. sanguinea and I. sanguinea f. albiflora. Its flowers are bright, with two colors (Fig. 1). The plant height of ‘Donglin Yixia’ (73.15 ± 0.25 cm) is higher than that of the parents, which were 57.02 ± 0.40 cm (I. sanguinea) and 57.13 ± 0.75 cm (I. sanguinea f. albiflora). The leaf length (79.64 ± 0.24 cm) and leaf width (1.58 ± 0.13 cm) of ‘Donglin Yixia’ are also higher than those of I. sanguinea (leaf length: 58.51 ± 0.72 cm; leaf width: 1.26 ± 0.02 cm) and I. sanguinea f. albiflora (leaf length: 56.60 ± 0.62 cm; leaf width: 1.20 ± 0.03 cm); additionally, its leaf length-to-leaf width ratio (50.40 ± 0.45 cm) is also higher than that of its parents. In terms of bracts, the bract length of ‘Donglin Yixia’ (bract length: 8.79 ± 0.17 cm) is approximately 2.5 cm longer than that of its parents (Table 1), and its width (0.89 ± 0.24 cm) is slightly narrower than that of its parents (approximately 0.1 cm). The width difference is not significant. The bract length-to-width ratio of ‘Donglin Yixia’ (9.87 ± 0.03 cm) is higher than that of its parents (I. sanguinea: 6.25 ± 0.43 cm; I. sanguinea f. albiflora: 6.08 ± 0.20 cm). In general, the bracts of ‘Donglin Yixia’ become longer and narrower than those of its parents. The flower diameter of ‘Donglin Yixia’ is 8.28 ± 0.20 cm. Compared with the flower diameter of its parents, which are 6.72 ± 0.20 cm (I. sanguinea) and 6.58 ± 0.05 cm (I. sanguinea f. albiflora), the flower of ‘Donglin Yixia’ is larger and has a better ornamental effect. The length of the inner perianth segment of ‘Donglin Yixia’ (4.59 ± 0.16 cm) was not significantly different from that of its parents; however, the inner perianth segment of ‘Donglin Yixia’ (1.81 ± 0.08 cm in width) was wider than that of its parents. Furthermore, its length-to-width ratio was smaller than that of its parents. In general, the inner perianth segment of ‘Donglin Yixia’ was fatter than that of its parents. During flowering, the outer and inner perianths of the parental species I. sanguinea f. albiflora and I. sanguinea exhibit white (RHS N155C) and blue–purple (RHS N88A) coloration, respectively. When ‘Donglin Yixia’ reaches full bloom, the outer perianth segment (Fig. 1B) exhibits a purple hue (RHS N81A), whereas the inner perianth (Fig. 1B) displays a light purple shade (RHS N81D). The flower showcases two distinct colors, thus providing a unique visual experience. In comparison with its parents, the cultivar Donglin Yixia exhibits enlarged flowers with distinct bicolor characteristics, thereby presenting an exceptional esthetic allure.
Anatomical structure of flowering and flowers of ‘Donglin Yixia’ and its parents. (A) The flowering elevation of ‘Donglin Yixia’. (B) The floral anatomy of ‘Donglin Yixia’. (C) The elevation of the flowers of I. sanguinea. (D) Floral anatomy of I. sanguinea. (E) The elevation of the flowers of I. sanguinea f. albiflora. (F) Floral anatomy of I. sanguinea f. albiflora.
Citation: HortScience 59, 10; 10.21273/HORTSCI18022-24
Cultivation Techniques
‘Donglin Yixia’ can be propagated by splitting in spring, summer, or early autumn. When dividing plants, two to three bud points should be reserved and planted with spacing of 40 × 40 cm. Generally, no fertilization is required, and diseases and pests rarely occur.
Habit and Application
‘Donglin Yixia’ has strong cold tolerance and disease resistance. It can overwinter in the open field in Heilongjiang Province, China. It likes light and humidity. The suitable growth environments include wet grasslands, waterside wetlands, and sunny slopes. ‘Donglin Yixia’ has high ornamental value and can be used for cut flowers and urban greening in cold areas.
Availability
Inquiries about research or requests for ‘Donglin Yixia’ plant materials can be made to Dr. Ling Wang (E-mail: wanglinghlj@126.com) at the College of Landscape Architecture, Northeast Forestry University, Harbin, China.
References Cited
Chen X, Liu NX, Fan LJ, Du Y, Wang L. 2019. ‘Zi Meiren’: A new Iris sanguinea cultivar. HortScience. 54(8):1435–1436. https://doi.org/10.21273/HORTSCI13856-19.
Fan LJ, Gao Y, Hasenstein KH, Wang L. 2021. ‘Flower Angel’: A new Iris sanguinea cultivar. HortScience. 56(5):617–618. https://doi.org/10.21273/HORTSCI15703-21.
Kuwantai A, Liu YJ, Wan ZZ, Liu HY, Wang L. 2018. ‘Forest Fairy’: A new Iris sanguinea Cultivar. HortScience. 53(8):1222–1223. https://doi.org/10.21273/HORTSCI13114-18.
Qi XY, Fan LJ, Gao Y, Shang YH, Liu HY, Wang L. 2020. ‘NEFU-1’: A new Iris sanguinea cultivar. HortScience. 55(1):109–111. https://doi.org/10.21273/HORTSCI14578-19.
Royal Horticultural Society. 2007. Royal Horticultural Society colour chart. Royal Horticultural Society, London, UK.
Yang J, Li FY, Zhou S, Fan LJ, Wang L. 2022. ‘Dong Lin Zi’: A new Iris sanguinea cultivar. HortScience. 57(2):197–199. https://doi.org/10.21273/HORTSCI16263-21.