Will the modified genes of grafted plants be inherited?

It seems that you are not talking about grafting...

Grafting can change some of the original characteristics. For example, grafting orange branches onto the stems of orange trees as rootstocks. The fruits produced are oranges instead of oranges. If you take the fruit produced by such a tree and plant it again, what you grow will still be oranges, not oranges. So from this aspect, grafting will not change genetic genes. It will continue to be inherited. Because the rootstock is not involved in the production of fruit.

As for the bougainvillea you mentioned, it is colorful. I am afraid it is not grafted, but a hybrid. If it is said to be grafted, it means that several colors of bougainvillea are grafted on one rootstock (I am not familiar with bougainvillea. I assume that one kind of bougainvillea is one color, not colorful), and it will indeed bloom when it blooms. It blooms flowers with distinct layers and is colorful, but this colorful color is produced by the main body of various bougainvillea. It has no combination of genes. Therefore, even if it bears fruit, its fruit will not have any color after planting. Colorful bougainvillea appear instead of a single color.

If you want to have colorful bougainvillea, you still need to hybridize or genetically recombine.

It was a bit chaotic, and I almost fainted. Hope you can understand.

I can’t help it, it’s early in the morning.

Sleeping.