Breeding report of a new wild jujube cultivar Jinsuan No. 1 (Ziziphus jujuba var. spinosa)

Abstract: Jinsuan No. 1 is an excellent cultival selected from high-quality wild jujube germplasm resources in Linxian county, Shanxi province. In 2006, the first investigation and screening of wild jujube cultivars were carried out in Linxian county, the dominant producing area of wild jujube. In 2007, 37 kinds of wild jujube cultivars with good performance were obtained from the selected wild jujube cultivar. In 2010, through the comparative investigation on grafting experiments, it was found that among the selected wild jujubes, No.3, No.8, No.9, No.21 and No.35 showed better comprehensive traits. Subsequently, a three-year comparative trial was carried out, and finally the No.3 wild jujube with the most excellent comprehensive traits was selected. In 2017, a large- scale grafting cultivation experiments were carried out in Linjiaping and Qikou of Linxian county, Yonghe county of Linfen and Taigu county of Jinzhong. Field identification was performed in September 2022 and the cultivar was received approval from the Forest Variety Approval Committee of Shanxi Provincial Forestry and Grassland Bureau in December, named Jinsuan No. 1 (Benefit number: Jin S-SV-ZJ-017-2022). Jinsuan No. 1 wild jujube tree shape is open and the tree vigor is moderate. Leaves are ovate-lanceolate, 2.5-6.8 cm longand 2.0-3.5 cm wide with leaf base slanting 1.1-2.9 mm; the petiole is 3-6 mm long; jujube hanging is 13-25 cm long. Jinsuan No. 1 wild jujube fruit is nearly round, the top of the fruit is flat, the pericarp is thin and red, and the fruit is large. The average single fruit weight is 4.75 g, the maximum single fruit weight is 5.8 g, the average transverse diameter is 1.9 cm, and the average longitudinal diameter is 2.2 cm; the flesh is thick, juicy, dense and crisp, sweet and sour, and the edible rate is 84.7% without residue. The soluble solids content is 27.6% , reducing sugar (glucose) content is 8.5% , total sugar content is 27.04%, VC content is 419 mg · 100 g- 1 , and titratable acid is 1.032%. The kernel is full, with a kernel rate of 100%, and the average single kernel weight is 0.1 g. The vegetative growth period is 170-180 days, and the fruit growth period is about 115 days. Jinsuan No. 1 wild jujube belongs to late-maturing cultivar, 20 days later than other common jujube cultivars in Linxian county. With Jinsuan No. 1 wild jujube, the bud break is seen around April 20, the early flowering period is in late May, the full flowering period is in early June, the fruit enters the crisp ripening period in mid-to-late September, the fruit maturity is in mid-to-early October, and the defoliation period is in late October in the mountains along the Yellow River in Linxian county, Lüliang City. The fruit cracking rate of Jinsan No. 1 is lower than 1.0%. Jinsuan No. 1 jujube cultivar is suitable for both fresh consumption and drying, and can also be used to process special drink and snacks. Jinsuan No. 1 is suitable for cultivation in the suitable growing areas of jujube in the south-central Shanxi province and somewhere with similar climates in China.