No, I haven’t seen that publication. I have watched the videos. I like that he covers multiple rootstocks and multiple training systems. Thanks for the link you posted.
Have you looked into why the B9 trees were smaller than expected? Is it a soil fertility issue, replant or did they just runt out? Even commercial orchards have problems with dwarf rootstocks runting out sometimes which is expensive for them. Do you have heavy soil? Even if the ground is fresh and your not replanting it’s possible that the microorganisms that cause replant disease are present at higher than expected levels which could slow growth.
I’m not 100% sure about the small size on the B9 but I believe its related to high soil temperature.
I saw some research from Australia that concluded that root growth on M9 trees was inhibited by high soil temperature so I believe high soil temp is part of the problem. Bud-9 was originally developed in a very cold climate in Russia so problems with high temperature makes sense
Nutrition levels and PH are good and I have drip irrigation. The agronomist did some test too and could not locate any problems. My peach trees grow like crazy with very little fertilizer in the adjacent row.
Not sure about the microorganisms that cause replant disease, The area was fallow for a number of years and never had any type of fruit trees
Edit: Forgot to mention that the apple PHD told me that how far the graft union is out of the soil has a impact on tree height and vigor. Once the trees settled, most of my graft unions were pretty close to the ground. The vigor of a few trees on each variety that are a few inches above the soil line may be slightly less
Thanks for the info. I got really interested in interstems after Steve at Skillcult.com did his videos on interstem grafting. I always like to hear about people’s experiences with interstems since there is little information available on them.