Investigation, collection and preliminary evaluation of genetic resources of Chinese cherry [Cerasus pseudocerasus (Lindl.) G. Don]

Abstract: 【Objective】Chinese cherry [Cerasus pseudocerasus (Lindl.) G. Don] was originated in China,and has been cultivated for more than three thousand years. In order to clarify its distribution, utilization and genetic diversities, we investigated the Chinese cherry germplasms distributed in 106 towns of 66 counties in 12 provinces of the China, and assessed important economic traits of the main accessions in last five years. The resources collection and major economic traits assessment were also performed to some excellent accessions. We hope these results can provide reference for the efficient conservation and utilization of Chinese cherry landraces.【Methods】The investigation and collection of Chinese cherry resources were made in the ripenning period of the fruits each year from 2010 to 2015. Firstly, the preliminary investigation scope was determined according to the information from peers, literature and the Inter-net. Then, the roadmap was drawn based on the local climate characteristics and different maturity period.Finally, the survey sites were determined according to the records of literatures and consultation with the local farmers. In order to reflect the existing situation of Chinese cherry landraces objectively, the representative accessions were collected on the spot during the investigation.【Results】(a) Chinese cherry is widely situated in variable habitats with various topographies and landforms for its great adaptability. It is mainly distributed in the southwest and northern parts of China, including Jiangsu, Zhejiang provinces,Yun-Gui plateau, Sichuan basin and northern China plain. Unfortunately, the number of genetic resources is decresing. The living situation seems an alarming rise of resources destruction. Landraces in many places run its own course, without any human management, and its distribution scales are also decreasing.For example, Linqu district(Shandong province), Nayong district(Guizhou province) and Hanyuan district(Sichuan province) have planted Chinese cherry with large-scale in the past decades, but only a few recourses exist currently. This phenomenon is associated with the rapid urbanization, road development and environment destroying. A large number of genetic resources are in danger. Moreover, another reason for the loss of landraces diversity is directional selection and cultivation.(b) Chinese cherry exhibited rich diversity in main fruit traits, such as peel color, fruit shape and size. Among the 60 representative accessions, the peel exhibited six different colors, although the main color was red. The fruit size ranged from0.95 cm/0.97 cm to 1.92 cm/1.78 cm( transverse /longitudinal diameter), the largest being 1.92 cm/1.78cm(Beichuan, Sichuan province) and the smallest being 0.95 cm/0.97 cm(Zaozhuang, Shandong province). Soluble solids content ranged from 10.97% to 34.00%, the highest being 34.00% from Dechang(Sichuan province) and the lowest 10.97% from Hanyuan(Sichuan province). The studied 60 representative cherry resources showed good productivity, about 70% of these accessions with high yield ability and only8.33% with low yield ability.【Conclusion】Chinese cherry has distinct advantages in adaption, resistance to pests, productivity and flavor traits. However, the small fruit size is a limiting factor in cherry industry.Larger size fruit is a main objective in the future breeding program. Meanwhile the existing excellent landraces accessions with large fruit size should be paid more attention, such as the individuals from Miyi,Pengzhou, Jianyang, and Luding in Sichuan province, and Zaozhuang in Shandong province, and Bijie in Guizhou province. Furthermore, we should also pay attention to the distinctive resources with great breeding potential, such as large fruit size and storage quality. For example, the individuals from Beichuan in Sichuan province, which are characterized by larger fruit transverse/longitudinal diameter(1.92 cm/1.78cm) and weigh(4.0 g). Finally, considering the results above, we strongly advise to make measures to preserve these valuable resources, including(a) Core germplasm collection of cherry resources should be constructed in the future. Thus it will be possible to conserve rare individuals with certain excellent agronomic traits in the ex situ conservation way and it will be also convenient to utilize these cherry resources collections, and(b) The study of genetic diversity of Chinese cherry resource should be carried out using molecular marker technology. We listed detailed information of the Chionese cherry resources in table 1. 471 leaf samples were dried in silica gel and deposited in our laboratory, and about 200 grafts and seeds from excellent landraces with breeding potential were planted in cherry resource nursery in Sichuan Agricultural University.