Authenticity Identification of F1 Hybrid Offspring and Analysis of Genetic Diversity in Pineapple

Breeding is an effective method for the varietal development of pineapple. However, due to open pollination, it is necessary to conduct authentic identification of the hybrid offspring. In this study, we identified the authenticity of offspring and analyzed the genetic diversity within the offspring F1 hybrids resulting from crosses between 'Josapine' and 'MD2' by single nucleotide polymorphism (SNP) markers. From the resequencing data, 26 homozygous loci that differentiate between the parents have been identified. Then, genotyping was performed on both the parents and 36 offspring to select SNP markers that are suitable for authentic identification. The genotyping results revealed that 2 sets of SNP primers, namely SNP4010 and SNP22550, successfully identified 395 authentic hybrids out of 451 hybrid offspring. We randomly selected two true hybrids and four pseudohybrids for sequencing validation, and the results have shown that two true hybrids had double peaks with A/G, while pseudohybrids had single peaks with base A or G. Further study showed that the identification based on SNP molecular markers remained consistent with the morphological identification results in the field, with a true hybridization rate of 87.58%. K-means clustering and UPGMA tree analysis revealed that the hybrid offspring could be categorized into two groups. Among them, 68.5% of offspring aggregated with MD2, while 31.95% were grouped with Josapine. The successful application of SNP marker to identify pineapple F1 hybrid populations provides a theoretical foundation and practical reference for the future development of rapid SNP marker-based methods for pineapple hybrid authenticity and purity testing.