I have a second year centennial that has been growing nicely since April 1st. I am training the two strongest bines up twine to a T shaped structure. Today, I noticed the tip of the biggest vine was limp. Closer, I saw that the bine had been cut about six inches down from the top. Not a clean, blade-like cut, but complete none-the-less. Also, on the same bine but about halfway up, right above a node is a two inch split, running lengthwise. It doesn't seem to be harming the bine, it is otherwise healthy and vigorous. Could it be from training them incorrectly around the twine? Also, now that the main bine has been severed, what shall I do? It is about 4.5 ft long at this time. Any similar experiences? There is nothing feeding on the plant, could wind have done this?