Mamuang,
As your aware most Asian pears do the same thing and will start producing quickly and runt a tree out. I’m starting to put Asian pears on Harbin rootstock and I love that rootstock! I would not use harbin under a European pear because of pear decline. BET rootstock is probably a really good choice for some early over producing pears but ive never seen a nursery use it for that purpose. There are nurseries such as St. Lawrence that sell on harbin due to the rootstock being able to handle colder temperatures. I’m working on using a few different rootstocks now for Charles Harris pears. Due to it’s reportedly large pear size I’m growing it on both callery and harbin. I’ve read pears can reach 3 pounds each Anyone else trying Charles Harris Asian Pear?