Confirmation of a purple-leaved plum graft hybrid.

Fifty-seven scions from an adult purple-leaved plum tree were grafted onto the crown of a 6-year-old Yuhuang plum tree and compared to the control of a non-grafted tree. The floral buds of the purple-leaved plum were fully removed before blossoming to avoid sexual hybridization between the two species. The seeds of the Yuhuang plum were picked in July and sown in the spring after stratification. Three, eleven and eight variants with purplish red leaves were found among the seedlings that grew from the seeds picked in 1999, 2000, and 2001, respectively. The ratio of variant occurrence ranged from 2.3 to 15.8%. Our results confirmed the observation of a graft hybrid by Luther Burbank.