Germplasm resources and genetic improvement of : A new fruit crop in China.

species, belonging to Lardizabalaceae, are widespread from subtropical to temperate environments of China, Japan, and Korea. All known species have medicinal and dietary value and have been widely cultivated as a new fruit crop in many areas of China. However, compared with other crop species, the breeding improvement and commercial cultivation of remain in their infancy. This review systematically introduces the present germplasm resources, geographical distribution, biological characteristics, interspecific and intraspecific cross compatibility, molecular biology, and breeding progress in species. plants are widely distributed in Shanxi, Henan, Sichuan, Chongqing, Hunan, Hubei, Jiangxi, Zhejiang, and Fujian provinces of China, and wild plants exhibit abundant phenotypic and genetic diversity due to their wide range of geographical distribution and high adaptability in different habitats. Interspecific artificial hybridization experiments have been conducted in our germplasm resources nursery. The results showed that there was no reproductive isolation between species, and fertile progeny could be produced. The synthesis of knowledge on these species provides insights for the rational development and utilization of these germplasm resources, and can facilitate the development of new breeding lines or varieties for commercial cultivation or production. Finally, perspectives on breeding research are discussed and conclusions are provided. This review provided breeders with new insights into domestication and breeding, and we also proposed five basic steps in the domestication of new fruit crops.