2016 Progress Report -Evaluation of the Cornell-GenevaApple Rootstocks and Other Promising Apple RootstocksHigh-Density Planting Systemsand Rootstocks for Sweet Cherries in the East

摘要

1. Graft Union Strength of Geneva Rootstocks. We finished several trials relating to graft union strength of various Geneva rootstocks, where in cooperation with Brent Black at Utah State University and MS student, Stuart Adams, we learned about strengths related to 1) method of grafting (chip bud vs. whip and tongue graft vs. machine V graft); 2) specific sci-on/rootstock interaction (several scions on several rootstocks); 3) and possible exogenous plant growth regulator treatments toincrease graft strength. Briefly, the weakest graft unions are obtained by grafting brittle stiff scions onto brittle rootstocks. The methods of grafting (chip budding vs. bench grafting) are similar in performance in weak combinations. There are treatments such as prohexadione calcium and 6-BA (benzylaminopurine) which seem to increase graft union strength. Different treatments and graft union combinations were imaged by X-Ray micro tomography at the Cornell Biotech Imaging Facility revealing interesting patterns of union formation. Data from micro-CT scans is still being analyzed to explain variation caused by the treatments.