Studies On The Genetic Variation And The Fruit Quality Of Zizyphus Jujuba Mill.cv.Dongzao From Different Provenances And The Cultivating Technology

Dongzao jujube (Zizyphus jujuba Mill. cv. Dongzao) is one of the famous fresh-eating cultivars of Chinese jujubes that matured in middle October. With the rapid development of Dongzao jujube's industry in recent years, some problems happened, such as the decline of fruit quality, changes in the shape, fruit quality vary among different original places, et al. The quality of Dongzao jujube was affected by many factors, Dongzao from different sources often has a distinct difference in fruit quality.So we established three parallel orchards in Shandong province, Zhanhua county, Hebei province, Huanghua and Cangxian county to test the fruit quality of Dongzao jujube, in order to analysis the main factor causing the quality difference. The trees were coming from 5 different original places, whose were Shandong province, Zhanhua, Qingyun and Laoling county; Hebei province, Huanghua and Cangxian county. At the same time, we also test the effect of several planting measures, such as fertilizing on the leaves, using GA₃ in the blossoming period and fruit growing time and the rudimental of the pesticide. The growing and fruit-setting traits of Dongzao jujube were also studied in this thesis.The results were as followed: The traits of Dongzao jujube from different original places such as the weight of the fruit, the shape of the fruit and the stone, the water content of the fruit, the edible ratio, the color of the fruit at harvest time, the content of the fruit's Vc, organic acid, sugar, and the soluble solid, as well as the the score of sense evaluation, had not significant difference in the same place of the orchard and in the same year. The AFLP molecular markers showed that there were not obviously difference among the Dongzao jujube from the 5 original places. So we could consider that Dongzao jujube that coming from Hebei and Shandong province were belonging to one cultivars, which had a very small distance of heredity.The reason causing the difference of the fruit quality of Dongzao jujube in different orchards and years were the different soil condition of the orchards, the weather ofdifferent years and the different cultivating methods, among which, using the fertilizer, hormone (GA₃) and the pesticide excessively were the main reason lead to the decline of the fruit quality.The result aslo showed the rules of the fruit-setting of Dongzao jujube, those were: the amount of the fruit on the older trees were more than on the younger trees, the amount of the fruit at the exterior was more than at the inside of the tree, the lower part of the tree was more than the top, the horizontal branches were more than the vertical ones, and the girdled trunks were more than the ones that not girdled. So we must follow the rules of the fruit-setting, establish the proper shape of the trees, actualize a proper way of cutting in the winter and summer, as well as girdling in the blossoming period, in turn create a favorable nutrition condition of the Dongzao jujube trees. In order to enhance the fruit quality of the Dongzao jujube, we must using more organic manure than the chemic fertilizer, fertilizing in the autumn and dressing at the proper time, control the concentration and times when using GA₃, using more biological, manual and agricultural method than the pesticides to control the pests and diseases.This thesis also made some suggestions on Dongzao jujube organical cultivating, and established an annual cultivating calendar for Dongzao jujube orchard.After a long time of productive cultivating, there were some very small heredity difference in the scope of Dongzao jujube cultivars. So the improvement of Dongzao jujube was mainly depend on the find and using of the single excellent trees. Until now, there were lots of difficulties in jujube cross-fertilizing breeding, we need more exploration in this field.