It sounds like you are growing the rootstock in competition with the graft. You need to get rid of the rootstock and make the graft the apical or highest growth which will grow vertically. Al

Thanks for answering. Where the rootstock and scion are joined the diameter is about 3/8 inch. The scion is taking a sharp turn to the right. About an inch or so below that is the rootstock, 43 inches tall and trying to grow vertically. How close to the main rootstock should I cut off the shoot heading vertically? Flush with the main rootstock, or leave a little nub? How much of a nub? What time of year is best to do this? Can I do it now? Should I put some kind of sealer on the part where I make the cut? This is the first time I have tried this and I would not want to make a mistake on it. Thanks for anymore information.

Cut it as close to the rootstock as possible. You won't have any growth from that point in the future. Don't seal it, sealers do nothing to improve healing and/or keeping infections out of the wound. Do it now before it gets to big. It's easier when small rather than when it gets bigger.

Thanks, I will trim the rootstock back today.

The graft will gradually become vertical and in five years as the caliper of the trunk increases the cut of the rootstock will disappear. Al