Apricots, scientifically known asPrunus armeniacaL, are drupes that resemble and are closely related to peaches or plums. As one of the top consumed fruits, apricots are widely grown worldwide except in Antarctica. A high-quality reference genome for apricot is still unavailable, which has become a handicap that has dramatically limited the elucidation of the associations of phenotypes with the genetic background, evolutionary diversity, and population diversity in apricot. DNA fromP. armeniacawas used to generate a standard, size-selected library with an average DNA fragment size of ~20 kb. The library was run on Sequel SMRT Cells, generating a total of 16.54 Gb of PacBio subreads (N50 = 13.55 kb). The high-qualityP. armeniacareference genome presented here was assembled using long-read single-molecule sequencing at approximately 70× coverage and 171× Illumina reads (40.46 Gb), combined with a genetic map for chromosome scaffolding. The assembled genome size was 221.9 Mb, with a contig NG50 size of 1.02 Mb. Scaffolds covering 92.88% of the assembled genome were anchored on eight chromosomes. Benchmarking Universal Single-Copy Orthologs analysis showed 98.0% complete genes. We predicted 30,436 protein-coding genes, and 38.28% of the genome was predicted to be repetitive. We found 981 contracted gene families, 1324 expanded gene families and 2300 apricot-specific genes. The differentially expressed gene (DEG) analysis indicated that a change in the expression of the 9-cis-epoxycarotenoid dioxygenase (NCED) gene but not lycopene beta-cyclase (LcyB) gene results in a low β-carotenoid content in the white cultivar “Dabaixing”. This complete and highly contiguousP. armeniacareference genome will be of help for future studies of resistance toplum pox virus(PPV) and the identification and characterization of important agronomic genes and breeding strategies in apricot.

Stone fruits (Prunus spp.) occupy a pivotal position in global fruit production due to their significant nutritional profile and distinctive organoleptic characteristics. Contemporary orchard systems are undergoing transformation through innovative cultivation approaches, notably high-density dwarfing systems, greenhouse cultivation, agri-tech integration, and simplified management. As a crucial agronomic component in modern stone fruit cultivation, rootstock systems confer multi-benefits including enhanced environmental resilience, improved scion productivity, superior fruit quality, controlled vigor, and dwarfing capacity. While the majority of European apple orchards have transitioned to dwarfing rootstock systems, achieving substantial gains in productivity and profitability, stone fruit cultivation lags significantly due to the key gaps in prunus rootstock development, including genetic complexity, extended evaluation cycles, clonal propagation barriers, and limited research programs. Urgent innovation is required to address these challenges in rootstock breeding to meet the demand of sustainable stone fruit production. This review systematically examines strategic breeding objectives and innovative molecular methodologies in prunus rootstock development, with particular emphasis on marker-assisted selection and genomic prediction technologies. We provide a comprehensive synthesis of breeding achievements across major commercial rootstock cultivars, while proposing forward-looking research strategies incorporating CRISPR-based genome editing and multi-omics approaches. The synthesized insights establish a theoretical pathway for advancing rootstock genetic improvement and sustainable orchard management practices in stone fruit cultivation systems.

Improving fruit quality is one of the most critical core tasks in fruit tree breeding. However, the complexity of the constituent factors of fruit quality and their interrelationships, the significant influence of environmental factors on quality, and the diversity of consumer demands, among other factors, make quality breeding a more challenging endeavor than other breeding objectives. Essentially, fruit quality is defined by the delicate balance of sugar, acid, and aromas, which collectively influence the fruit’s flavor, consumer satisfaction, and economic value. While substantial progress has been made in the depiction of the metabolic pathways underlying these traits, the molecular mechanism coordinating carbon partitioning and competition between sugars, acids, and volatiles remains unknown. This review focuses on recent advances in understanding stone fruit metabolism and identifies key gaps in knowledge. We emphasize the need for integrated approaches combining spatial metabolomics, transcriptomics, genetics, and genomics to reveal the regulatory networks underlying metabolomic variation during fruit development and ripening. We also discuss the application of molecular tools, such as marker-assisted selection and metabolite-associated markers, to accelerate the breeding of flavor-balanced stone fruit cultivars. By adapting these advances in breeding practices, we can achieve coordinated improvement and precise regulation of various components of fruit quality, thereby developing elite stone fruit cultivars with improved flavor that meet prevailing consumer demands.

Apricot (Prunus armeniaca L.) exhibits a gametophytic self-incompatibility (GSI) system. To identify the S-genotypes of the main apricot cultivars, including 133 native Chinese cultivars and 35 foreign accessions, PCR was performed using a combination of five primers based on the conserved regions of Prunus S-RNase genes. After cloning and sequencing the PCR products, the S-genotypes of all 168 apricot cultivars were determined. A total of 46 different S-RNase alleles, with 15 new alleles, were identified. For all 168 accessions, the top five most frequent S-alleles were S₈, S₁₁, S₉, S₁₆, and S₅₃. S₁₁, S₈, and S₁₆ were the most frequent in Chinese cultivars, and S₉, S₈, and S₂ were mostly found in European accessions. For Chinese apricot cultivars, the distribution of S-alleles among five geographic regions was also investigated. In Northwest China, S₁₆ was the most frequent S-allele. In the Xinjiang region, S₆₆, S₄₉, and S₁₄ were the top three most frequent S-alleles. In North China, S₈, S₁₁, and S₅₃ were the top three most frequent S-alleles. In addition, the self-compatible type, S_C, was not detected in these 133 Chinese accessions. Finally, the phylogenetic tree of apricot S-alleles indicated that there are four groups of S-RNase genes (S₉₇/S₁₀₆, S₁₄/S_14a/S₆₆, S₉/S₁₇/S₄₄, and S₂₃/S₅₃) presenting a very close relation. These results provide more data on the S-genotypes of apricot accessions, which can support future breeding programs by aiding in the selection of the appropriate parents and contributing to efficient orchard design by combining cultivars with suitable pollinizers.

"Jingren 2: A New Kernel-using Apricot Cultivar of Prunus armeniaca × Prunus amygdalus" published on Dec 2024 by American Society for Horticultural Science.

Stone fruits (Prunus spp.) occupy a pivotal position in global fruit production due to their significant nutritional profile and distinctive organoleptic characteristics. Contemporary orchard systems are undergoing transformation through innovative cultivation approaches, notably high-density dwarfing systems, greenhouse cultivation, agri-tech integration, and simplified management. As a crucial agronomic component in modern stone fruit cultivation, rootstock systems confer multi-benefits including enhanced environmental resilience, improved scion productivity, superior fruit quality, controlled vigor and dwarfing capacity. While the majority of european apple orchards have transitioned to dwarfing rootstock systems, achieving substantial gains in productivity and profitability, stone fruits cultivation lag significantly due to the key gaps in prunus rootstock development include genetic complexity, extended evaluation cycles, clonal propagation barriers and limited research programs. Urgent innovation is required to address these challenges in rootstock breeding to meet the demand of sustainable stone fruits production. This review systematically examines strategic breeding objectives and innovative molecular methodologies in Prunus rootstock development, with particular emphasis on marker-assisted selection and genomic prediction technologies. We provide a comprehensive synthesis of breeding achievements across major commercial rootstock cultivars, while proposing forward-looking research strategies incorporating CRISPR-based genome editing and multi-omics approaches. The synthesized insights establish a theoretical pathway for advancing rootstock genetic improvement and sustainable orchard management practices in stone fruit cultivation systems.