Fruit scientific research in New China in the past 70 years:Cherry

Abstract: In the past 70 years, cherry scientific research in New China has achieved rapid development. The total cherry plantation in China reached about 266 000 hm2 by 2018, including the sweet cherry for about 233 000 hm2 and Chinese cherry for about 33 000 hm2, with the total production of 1 700 000 tons. After decades of development, more than 500 collections of cherry germplasms are preserved.Sweet cherry breeding program started in 1960's, till now, more than 40 new cultivars are released.‘Hongdeng', bred in 1976, is the most successful cultivar, which planted up to 40% of the total sweet cherry cultivation in China. Other promising new cultivars would be‘Chunlu'‘Luying3'‘Miquan'‘Fuxing', etc. Besides, more than 10 rootstock cultivars were released, including‘Landing 2'‘Jingchun'‘Y1'etc. In molecular assisted breeding, self-fertile allele S4'could be detected by PCR makers using the 4 bp deletion in the S4'SFB, fruit color trait could be selected by screening PavMYB10.1, a key gene in the anthocyanin synthesis pathway. A genetic map using a cross between cultivars‘Wanhongzhu'and‘Lapins' is built with a distance of 0.96 cM, and QTLs such as sugar-acid ratio and fruit size are located. Five most polymorphic SSR markers, along with S-genotype, are found to be able to distinguish 95 sweet commercial cherry cultivars, furthermore, this DNA fingerprinting method has been commercially applied in the authenticity and purity identification of cherry cultivars. Transgenic plants were reported using rootstocks such as Gisela6, Colt, CAB-6 p, Landing2, and selections from P. pseudocerasus. Tissue regeneration technologies limits transgenic research in P. avium. Compared with in vitro propagation, Cutting is superior in low expenses and simply facilities, and finally developed as a major rootstock propagation method for Gisela, Landing, Jingchun, and CAB etc. RT-PCR, multiplex PCR, and small RNA sequencing are used for cherry virus identification, in order to produce virus free propagation materials. More than 20 viruses are found and identified in sweet cherry so far in China, including Prunus Necrotic Ring spot Virus, Prune Dwarf Virus, Cherry Green Ring Mottle Virus, Little Cherry Virus 1, Little Cherry Virus 2, Cherry Virus A, Cherry necrotic rusty mottle virus, Cherry rasp leaf virus, Cucumber mosaic virus, Plum bark necrosis stem pitting-associated virus, Hop stunt viroid,Candidatus Phytoplasmas ziziphi, etc. Major sweet cherry plantation regions include Bohai Bay area and Longhai railway line. Bohai bay region includes Yantai, Tai'an in Shandong, Dalian in Liaoning,Beijing, and Qinhuangdao in Hebei. And along the Longhai railway line, there are Zhengzhou in Henan,Shaanxi, south Shanxi, and Tianshui in Gansu, etc. Furthermore, new plantations are expanding in the southwest high elevation areas and in the far northwest such as Xinjiang province. Chinese cherry(P.pseudocerasus), which is mainly used for fresh consuming and picking up tourism, is commercially planted in southern and southwest of China, such as Yangtze river basin and Sichuan, Guizhou, and Yunan provinces, where sweet cherry cultivation is somewhat limited by climate factors. Central Leader is the most popular used training system, and very new training system such as TSA, SSA, KGB, UFO, BiAxis, Tri-Axis, and Trellis were under testing in different locations. Plant regulator were found useful to control vegetative grow, promoting flower differentition, inducing parthenocarpy and improving fruit qualities. In recent years, green house plantation grows up quickly to about 13 000 hm2, and gradually typified by the following 2 types of greenhouse cultivation. Dalian Greenhouse type is constructed with a thick solid walls, at north back and both sides for storing solar energy and keeping warmness, has been effectively applied in northern areas, especially in Liaoning province. The other one, Linqu TallFrame-Greenhouse type, equipped with rolling quilts to keep warm, is featured with the height of about 7 m to 10 m, normally width of above 20 m, length of 60 m to 100 m, this bigger size type increases land use efficient and machinery mobility. Greenhouse cherry trees produce top quality cherries with high and stable yields in earlier season from February to May, ensuring good selling price. Post-harvest researches focused on disease control and logistic storage. CA and MA storage were investigated, and MA is found convenient and low cost for short term storage and logistic storage in sweet cherries.