In vitro regeneration and validation
We collected the branches with floral buds from an elite male P. tomentosa clone (LM50), and water-cultured in a greenhouse. Subsequently,we performed anther induced regeneration referencing previous study (Y. Li et al., 2013). The ploidy of regenerated anther plantlets were analyzed using a Cell Lab Quanta SC (Beckman Coulter, CA, USA) and chromosome counting. Furthermore, The genotype of anther plantlets were identified using 19 pairs allele-specific primers (Table S1). The detailed description was attched to supporting information (File S1).