-flowers (Zhang et al., 2021); less than 5% of 1200 floweringcrabapple cultivars are semidouble or double-flowered ( Fiala, 1994 ); and later blooming and double-flowers cultivars are extremely scarce. In China, the controlled breeding of modern crabapples began
Floweringcrabapple is the broad-sense term for plants from the genus Malus (Rosaceae) that have a small fruit diameter (≤5 cm). They have colorful, attractive blossoms (purple, red, pink, white, etc.) as well as fruits of outstanding ornamental
( Fan et al., 2019 ; Zhou et al., 2019 ).
There are nearly 1200 floweringcrabapple cultivars, with about 100 commonly supplied in today’s global market ( Fiala, 1994 ). However, less than 5% of these cultivars are semidouble or double pedals flowers
flower shape, and good stability and ornamental properties. The elite cultivars also enrich the diversity of crabapples and make up better flowering plant combinations in garden designs.
Yun Xiangrong [Note: from 《Qingping Tune》made by Li Bai, a poet of
. 2019 ), and ‘Jingxiu Hong’ ( Sha et al. 2021 ). The breeding trend for floweringcrabapples continues to be new varieties with unusual flower shapes, double petals, and novel flower colors.
Yunjuan Yunshu is a new cultivar selected and released for
≈1200 crabapple varieties, with about 100 commonly supplied in today’s global market. Unfortunately, double-petal varieties of floweringcrabapples are relatively scarce ( Fiala, 1994 ). In the past 20 years, only two new double-flower crabapple
Information on ploidy levels is extremely valuable for use in plant breeding programs. Fertility, crossability, and heritability of traits are all influenced by ploidy levels. Knowledge of reproductive pathways, including occurrence of apomixes, pseudogamy, and formation of unreduced gametes can also be important information for developing breeding strategies. Although ploidy level can be determined by counting chromosomes, flow cytometry provides a reliable and much faster means for determination of nuclear DNA content and associated ploidy level. Measurement of ploidy levels of seeds (embryo and endosperm) can also provide useful insights into reproductive pathways. The objective of this study was to determine the approximate genome size, estimated ploidy level, and range of reproductive pathways of a diverse collection of flowering crapbapples (Malus spp.). Genome sizes were calculated as nuclear DNA content for unreduced tissue (2C). Results from the taxa included in our survey showed DNA contents ranging from 1.52 to 1.82 for diploids, 2.40 to 2.62 for triploids, and 3.36 to 3.74 pg/2C for tetraploids. Based on these ranges, we identified 43 diploid, 10 triploid, and 4 tetraploid crabapple taxa in this collection. Results from open pollinated seeds and seedlings demonstrated a variety of reproductive pathways including apomixes and unreduced gametes. This research provides information on ploidy levels and reproductive pathways of flowering crabapples and will allow for more systematic and efficient progress in the development of improved cultivars.
adaptability and pest and disease resistance in Jiangsu Province, China.
‘Juan Zhulian’ is a new ornamental crabapple cultivar selected by natural hybridization. In Spring 2011, nine flowering Malus crabapple cultivars—Purple Prince, Indian
The change from juvenile to adult phase of seedlings of tea crabapple [(Malus hupenhensis (Pamp.) Rehd.)] is influenced by 2 factors, the height and the age of the plants. Seedlings grown continuously in the greenhouse are unbranched and undergo phase change from juvenile to adult in 7 to 10 months at a height of approximately 2 m. Trees can be in bloom within 1 year from the time of seed germination. In contrast, seedlings grown periodically in the greenhouse or in the field are branched and produce more shoot growth but are shorter and take longer to flower. Greenhouse-grown seedlings can be brought into flower by chilling for 6 weeks or more, by withholding water until the leaves drop, or by treating the buds with cytokinins and gibberellins. Young seedlings cannot be stimulated to flower by grafting onto older seedlings although older seedlings will continue to form flower buds after grafting onto young seedlings still in the juvenile phase.