Observation of Embryo Abortion Characteristics of Ziziphus jujuba Mill. 'Zhongqiusucui'

The embryo abortion rate of Ziziphus jujuba Mill. 'Zhongqiusucui' is high, which hinders cross-breeding. Research to identify the causes of embryo abortion is urgently required. To determine the embryo abortion pattern and create a foundation for further research, the embryo abortion characteristics of Z. jujuba Mill. 'Zhongqiusucui' were observed during this study. The results indicated that Z. jujuba Mill. 'Zhongqiusucui' was a cultivar with a high embryo abortion rate. Furthermore, there were some differences in the embryo abortion rates of jujube fruits in different batches. There was no significant difference between the first and second batches of jujube fruits. Large jujube fruits had a relatively low embryo abortion rate. Small jujube fruits had a relatively low kernel content rate and high embryo abortion rate. Most of the jujube fruits contained a single kernel, and some contained double kernels. The third batch of jujube fruits differed greatly from the first and second batches. The third batch had the highest degree of embryo abortion and all contained kernels were single. The embryo abortion degree of jujube fruits on the lignified bearing shoot was higher than that on the nonlignified bearing shoot, and the probability of jujube fruit with double kernels on the nonlignified bearing shoot was higher than that of the fruit on the lignified bearing shoot. The embryo abortion rates of jujube fruits with a smaller fruit shape index and larger fruit shape index were lower, and that of the medium (fruit shape index range, 1.30-1.60) was higher. The embryo abortion rates of globose, oblong globose, and long cylinder jujube fruits were lower, whereas that of cylindrical fruits was higher. Cracked jujube fruits did not contain normal seed kernels and their embryo abortion rate was 100%.