Integrated cytogenomic analysis of Physalis germplasm using CMA/DAPI chromosome banding and flow cytometry

Understanding genome organization is fundamental for the characterization of plant genetic resources and for supporting conservation and breeding strategies. The genus Physalis (Solanaceae) comprises species of considerable biological, nutritional, and medicinal importance, including Physalis peruviana , P. angulata , and P. ixocarpa . Previous cytogenetic studies have reported a basic chromosome number of x = 12, with chromosome complements ranging from 2n = 24 to 2n = 48. In the present study, cytogenomic variation among Physalis germplasm accessions was investigated through the integration of CMA/DAPI chromosome banding and flow cytometry. Cytogenetic analyses revealed substantial variation in heterochromatin distribution and chromosome banding patterns among accessions, whereas flow cytometry detected differences in nuclear DNA content and ploidy levels. Significant intra- and interspecific variation was identified, indicating ongoing genomic differentiation within the evaluated germplasm. Distinct cytogenomic patterns were observed among the analyzed species, including diploid and tetraploid accessions, as well as accessions exhibiting multiple nuclear populations. Three major heterochromatin banding patterns were identified (DAPI⁺/CMA⁻, DAPI⁺/CMA⁺, and CMA⁺/DAPI⁻), with predominance of subterminal heterochromatic regions across most chromosomes. To our knowledge, this is the first comparative cytogenetic study integrating CMA/DAPI fluorochrome banding and flow cytometry in germplasm accessions of P. peruviana , P. angulata , and P. ixocarpa . The combined application of these approaches provides valuable insights into genome organization, ploidy variation, and genetic diversity within the genus Physalis , contributing to germplasm characterization and the conservation and utilization of plant genetic resources.