The research on the genetic predisposition of key quality traits of fruit in jujube hybrid populations is a fundamental and crucial aspect in the field of jujube genetic breeding. In this study, the jujube hybridization experiments were conducted with the same female parent and different male parents since 2015, and a total of 238 strains were created in two F1 hybrid populations. The genetic variation of fruit external traits and intrinsic quality was analyzed and compared after the hybrid offspring results were stable in 2022. This study can provide a theoretical basis for selecting hybrid-breeding parents, predicting offspring traits, and innovating excellent germplasm resources by investigating the impact of different male parental configurations on the genetic variation of fruit traits in jujube hybrid offspring and identifying superior germplasm resources. The results showed that the inheritance of fruit shape, fruit size, and fruit-intrinsic nutrition-quality traits were quantitative traits controlled by multiple genes, and the offspring populations conformed to normal distribution or partial normal distribution. The six traits of fruit shape in offspring populations exhibited a segregation from their parents. The coefficients of variation of fruit size and intrinsic nutrition quality values ranged from 6.94% to 35.34%. Five intrinsic nutrition-quality traits exhibited significant separation at the super-parental level. This result indicated a rich genetic diversity in offspring traits in two hybrids offsprings. The fruit shape, fruit size, and titratable acidity of jujube hybrid offspring were mainly influenced by the male parent. It was found that the correlation between the single-fruit weight, length, and diameter, as well as the correlation between the fruit length and fruit transverse diameter, was very stable and significantly positive through the correlation analysis. More attention should be paid to fruit length when studying fruit shape, as a significant correlation was found between fruit length and fruit shape index. Finally, 10 superior hybrids were founded and selected as breeding materials for further breeding. Therefore, this study provides a theoretical basis for the early selection of hybrid breeding and the development and application of jujube germplasm resources.

Pyrus bretschneideri ‘Xinli No.7’, a progeny of Pyrus sinkiangensis ‘Korla Fragrant Pear’, is an early-maturing, high-quality pear (Pyrus spp.) cultivar. As a dominant variety in China’s pear-producing regions, it holds significant agricultural importance. Investigating its male sterility (MS) mechanisms is critical for hybrid breeding and large-scale cultivation. Integrated cytological, physiological, and transcriptomic analyses were conducted to compare dynamic differences between male sterility (MS, ‘Xinli No.7’) and male-fertile (MF, ‘Korla Fragrant Pear’) plants during anther development. Cytological observations revealed that, compared with ‘Korla Fragrant Pear’, the tapetum of ‘Xinli No.7’ exhibited delayed degradation and abnormal thickening during the uninucleate microspore stage. This pathological alteration compressed the microspores, ultimately leading to their abortion. Physiological assays demonstrated excessive reactive oxygen species (ROS) accumulation, lower proline content, higher malondialdehyde (MDA) levels, and reduced activities of antioxidant enzymes (peroxidase and catalase) in MS plants. Comparative transcriptomics identified 283 co-expressed differentially expressed genes (DEGs). Functional enrichment linked these DEGs to ROS-scavenging pathways: galactose metabolism, ascorbate and aldarate metabolism, arginine and proline metabolism, fatty acid degradation, pyruvate metabolism, and flavonoid biosynthesis. qRT-PCR validated the expression patterns of key DEGs in these pathways. A core transcriptome-mediated MS network was proposed, implicating accelerated ROS generation and dysregulated tapetal programmed cell death. These findings provide theoretical insights into the molecular mechanisms of male sterility in ‘Xinli No.7’, supporting future genetic and breeding applications.

Copy number variation (CNV) is a common source of genomic structural variation by altering the number of DNA fragments, which in turn affects phenotypic variation and gene expression levels. However, there have been no reports of CNV in Chinese jujube (Ziziphus jujuba Mill.). In this study, we identified 16,570 CNVs from “Yuhong” × “Jiaocheng 5” and 140 hybrid progeny materials, of which 3607 CNVs were deletion type and 12,963 CNVs were duplication type. The distribution of CNVs in the Chinese jujube genome was systematically described, and the CNV genetic map of the whole genome level of the Chinese jujube hybrid offspring was constructed. Based on the field investigations, 13 individuals with severe black spot disease and no disease were analyzed for trait association. A total of 1837 CNVs were detected at the significant level of association, of which 1371 were duplication type and 466 were deletion type. And the GO (Gene Ontology) annotation item identified a systemic acquired resistance (SAR), and eight genes related to disease resistance were screened by the annotation. After validation by qPCR, these results further support the potential role in regulating black spot disease resistance. The constructed genome-wide CNV map of the hybrid progeny of Chinese jujube provides a new way of thinking for understanding the genetic basis of phenotypic variation of complex traits in Chinese jujube.

BBX transcription factors are key regulators of plant growth, development, and stress responses, yet their functions in jujube (Ziziphus jujuba Mill.), an economically important fruit tree, remain largely unexplored. Here, we systematically identified 26 ZjBBX genes and comprehensively analyzed their phylogenetic relationships, structural features, and expression dynamics. Our integrative approach revealed three major findings. First, nine ZjBBX genes exhibited distinct expression patterns during fruit coloration, with ZjBBX9 and ZjBBX25 emerging as persistent up-regulated candidates. Second, under salt stress, ZjBBX members displayed three contrasting response modes, sustained down-regulation, rapid induction, or sharp repression, suggesting functional diversification in salinity adaptation. Third, under jujube witches’ broom, ZjBBX8, ZjBBX11, and ZjBBX13 showed differential expression between healthy and infected materials, implicating them in biotic stress defense. Collectively, this study provides the first multidimensional expression atlas of the ZjBBX family linked to fruit quality, salt tolerance, and pathogen resistance in jujube. Our findings open new avenues for marker-assisted breeding and genetic improvement of stress-resilient jujube cultivars.