The Change Law Of Jujube Fruit Kernel Content And Its Influencing Factor

Jujuebe(Ziziphus jujube Mill.)is the original characteristics of Chinese forest fruit.Sour jujube(Z.jujube var spinosa Hu)is the wild type of cultivated jujube.Jujube evolved from the sour jujube.Under natural conditions,the kernel rate of wild jujube is generally very high,while the kernel rate of cultivated dates varies greatly,and most of them have low kernel rate.In order to study the mechanism of the change of fruit kernel rate during the evolution process from wild jujube to jujube,and to provide a better theoretical and technical basis for jujube hybrid breeding,this study selects the national jujube germplasm resource nursery and the red jujube resource nursery in Qingjian,Shanxi.A total of 287 samples of wild jujube germplasm were collected from 2018 to 2019,including wild jujube 92 and jujube 195.10 traits such as single fruit weight,edible rate,kernel content,fruit shape index,and nuclear shape index were investigated;Dongzao with high kernel content was selected(?)and the hybrid progeny population of Jinsi No.4(?),which has genetic characteristics of wild jujube,investigate the kernel rate and fruit characteristics.Three representative germplasms of sweet wild jujube,Jun jujube and Xiangfen round jujube were selected for field gibberellin(GA)treatment to investigate the effect of gibberellin on endogenous hormones and kernel content.Using on-site investigation and control experiments,liquid-mass spectrometry(LC-MS)and other technologies,the main results are as follows:(1)Comparison of fruit characters and kernel content of wild jujube and jujube.Studies have found that wild jujube fruits are generally relatively small,with a single fruit weight ranging from 2.3 to 6.0 g,and an edible rate below 95.0%.The shape of the fruit is mainly round,with a core weight ranging from 0.1 to 0.5 g and a kernel rate of 80.0 to 100.0%.The single fruit weight of jujube fruit is 6.0-35.0g,and there are 4 varieties above 25.0g.The edible rate of most jujube varieties is above 95.0%,and a few are between 93.0%-95.0%,and only a few varieties have an edible rate below 93.0%;most jujube varieties have low or medium kernel content,and jujube varieties with high kernel content.less.Correlation analysis results show that the kernel rate is inversely related to the edible rate,fruit shape index,and kernel shape index.The edible rate of wild jujube is the lowest,the kernel rate is the highest(mostly 100%),and most of them are double kernels;The edible rate is 93.0%-99.0%.As the edible rate of jujube increases,the kernel rate decreases;and the kernel rate of round fruits is generally higher than that of long fruits.(2)The characteristics of kernel rate in hybrid offspring populations.Dongzao with round fruit and high kernel content is the female parent,and Jinsi No.4,which has genetic characteristics of wild jujube(round and high kernel content),is the male parent.A total of 64 hybrid offspring were investigated.The progeny traits are round(39.06% of strains),oval(26.56%),oblate(9.38%),cylindrical(6.25%),obovate(17.19%)and Malformed fruits(accounting for 1.56%),found that the kernel content is generally relatively high,almost nothing to do with the fruit shape.The study found that the female parent'Dongzao' naturally has a high kernel content,while the male parent'Jinsi No.4'has the characteristics of the golden silk series.The genetic structure has the characteristics of wild jujube and the kernel content is high.After the two crosses,the round fruit line has a higher kernel content,but the fruit content of each fruit-shaped line is more than 84.0%.From the fruit size,the kernel content is related to the fruit size It is not obvious,indicating that the genetic characteristics of controlling kernel rate in wild jujube significantly affect the kernel rate of jujube fruit.(3)The role of gibberellin in the regulation of jujube fruit kernel rate.Field trials found that the high kernel content sweet wild jujube,high kernel content round fruit-shaped Xiangfen round jujube,no kernel or very low kernel content long fruit-shaped jujube,the kernel content of gibberellin treatment is 0 after 40 days,indicating that gibberellin It plays an important role in increasing fruit size and inhibiting seed kernel development.Sweet wild jujube,Xiangfen round jujube and Jun jujube respectively represent three hormone regulation modes,namely jujube or jujube with the characteristics of jujube,round fruit-shaped jujube with high kernel content,large fruit-shaped or long-fruit-shaped jujube with low kernel content and other hormone regulation mode.The study found that the high kernel rate of cultivated jujube with genetic characteristics of wild jujube has deepened the understanding of the kernel rate of jujube fruit,and provided perspectives and research materials for in-depth exploration of the molecular mechanism affecting the kernel rate of jujube fruit.Based on the above analysis,the study summarized four regulatory models of jujube with high kernel content-double kernel,jujube with high kernel content with genetic characteristics of jujube,high kernel content in jujube fruit-single kernel,and low kernel content in jujube fruit / no kernel.For large or long-shaped fruits,normal cross-pollination and fertilization usually occur around 28 days after the flowering of embryo abortion,which causes low kernel or no kernels in jujube fruits;however,the induced parthenocarpy in a single variety of jujube orchards will cause All without benevolence.The research system reveals the mechanism of the kernel rate change during the domestication of wild jujube to jujube,and provides theoretical and technical basis for a wide range of jujube hybrid breeding.