Yellow-horn (Xanthoceras sorbifolium Bunge), a plant endemic to northern China, is resistant to drought, cold, saline stress, and barren soil, but cannot withstand excess moisture (Ao et al., 2012). Yellow-horn has been cultivated for more than 6000 years in China. It is an oilseed crop, and the oil content of the seeds can be as high as 65%. The oil can be used for cooking, as well as for medicine and biofuel production (Liu et al., 2017). The seed oil has traditionally been used for cooking and lighting. In recent years, the development and use of biodiesel produced from yellow-horn have received increased attention as a result of the energy crisis. The seed kernels of yellow-horn are rich in nutrients and contain 55% crude fat, 15% soluble sugar, and mineral elements (Xie and Zhang, 2018). Yellow-horn is widely distributed and shows extensive morphological variation, especially in flower type and color. It is also widely used as a landscaping tree species (Gao et al., 2002; Xu et al., 2010). Because of its high ecological, economic, and ornamental value, the cultivation of yellow-horn has received much attention in China in recent years.
Great progress has been made in the cultivation of new yellow-horn varieties (Wang et al., 2019). The flowers of most cultivars of yellow-horn are yellow at the base of the petals at the early flowering stage and white from the middle to the apex. The petal base turns purple-red at the full-bloom stage. The part from the middle to the apex of the petal is still white at this stage. In the novel cultivar ‘Yan Dong’, the base of the petal is yellow-green (Y-G 151D) at the early flowering stage, and the part from the middle to the apex is yellow-white to white (W 155B). At the full-bloom stage, the base of the petal is orange-yellow to orange-red (Y 11A to Y-O 16A). The part from the middle to the apex of the petal is yellow-white (O-W 159D) (Table 1). There are yellow to orange-yellow (Y 10B to Y-O 22A) veins that extend longitudinally from the base to the middle and upper parts. The genetic characters of ‘Yan Dong’ are stable, and it has high ornamental value with a special flower color. In Dongying City (lat. 37°45′N, long. 118°58′E), Shandong Province, ‘Yan Dong’ enters the early flowering stage in late April, and the florescence lasts ≈25 d. It can be planted in Northeast, Northwest, and North China.
The colors of the flowers during each flowering period of ‘Yan Dong’.
Ao, Y., Duan, J., Yu, H.Y., Jiang, C.Y. & Ma, L.Y. 2012 Research progress on Xanthoceras sorbifolia Bunge Zhongguo Nongye Daxue Xuebao 17 6 197 203 https://doi.org/CNKI:SUN:NYDX.0.2012-06-026
Liu, Y.L., Huang, Z.D., Ao, Y., Li, W. & Zhang, Z.X. 2017 Transcriptome analysis of yellow horn (Xanthoceras sorbifolia Bunge): A potential oil-rich seed tree for biodiesel in China PLoS One 8 9 e74441 https://doi.org/10.1371/journal.pone.0074441
Wang, X., Zheng, Y.Q., Su, S.C. & Ao, Y. 2019 Discovery and profiling of microRNAs at the critical period of sex differentiation in Xanthoceras sorbifolium Bunge Forests 10 12 1141 https://doi.org/10.3390/f10121141
Xie, Z.Y. & Zhang, W.H. 2018 Effects of drought and rewatering on growth and photosynthetic physioecological characteristics of Xanthoceras sorbifolia J. Appl. Ecol. 29 1759 1767 https://doi.org/10.13287/j.1001-9332.201806.007
Xu, D.X., Yu, H.Z., Wu, Z.Y., Hu, C.Y., Wang, Y., Yu, Y. & Lu, G.J. 2010 Xanthoceras sorbifolium biology 1 8 Beijing Science Press Beijing, China