Karyotype alterations, meiotic abnormalities, and reduced pollen viability in triploid cytotypes of Passiflora foetida (Passifloraceae) derived from endosperm cultures

Abstract The polyploidy induction offers the possibility to generate new variations in plant shape, color, fragrance, form, shelf life, flower architecture, and adaptability to adverse environments. Considering the importance of such information for understanding the effects of triploidy and homologous diploid on the reproductive biology of this cytotype of Passiflora foetida. To better understand the effects of triploidy on the reproductive biology of Passiflora foetida, this study aimed to compare the karyotype, meiotic behavior, and pollen viability of diploid and triploid cytotypes. Karyotyping, heterochromatin patterns, meiosis, and pollen viability assessments were conducted using differential DAPI and chromomycin A3 (CMA3) staining. As expected, diploid plants exhibited normal meiotic behavior, with approximately 75% viable pollen, whereas triploid cytotypes displayed abnormalities in both meiotic divisions and had approximately 70% unviable pollen. Despite these irregularities, triploid cytotypes demonstrated greater chromosomal stability in somatic cells compared to diploids. Given that chromosomal behavior plays a key role in reproduction and fertility, these findings provide valuable insights for breeding strategies and the development of improved P. foetida cultivars with desirable traits.