Integrating multiomics and modern breeding tools for accelerating genetic improvement in Annonas.

Custard apples (Annona spp.) are among the most important horticultural crops in the world, including Australia. The genus Annona comprises several economically and nutritionally significant species, including atemoya, cherimoya, sugar apple, ilama, soursop, bullock's heart, and bibra. These fruits are valued for their exotic taste and are popular backyard fruit crops in many countries. While some species are commercially cultivated and exported, the broader potential of these crops remains largely untapped. Despite their historical significance, these Annona species remain neglected or underutilised, with breeding efforts restricted to only a few countries. Extensive genetic resources, including germplasm collections, candidate genotypes, and mapping populations, are available for crop improvement. Traditional breeding methods - such as selection, crossbreeding, and mutation breeding - have been widely applied alongside modern breeding approaches like marker-assisted selection (MAS). However, several challenges, such as a lack of information regarding the crop and a long juvenile period, hinder crop improvement in custard apples. Recent advancements and affordability of sequencing technologies have enabled an increase in the number of multiomics studies, especially genomics and transcriptomics within Annona species. Integrating these data with proteomics, metabolomics, and phenomics will facilitate the genetic dissection of important traits in Annona. This review provides a comprehensive overview of the current advancements and future prospects of multiomics tools and technologies developed and their potential to accelerate custard apple breeding programs.