My apple bread recipe called for adding the sugar in with the sourcream, eggs and vanilla. I forgot to add the sugar until the dry ingredients and the apples were added. I added the sugar to the batter just before putting it in the oven. Will this make a difference in the taste or texture?
It is a bit of a guessgame without having seen the exact recipe, but applebreads tend to use rather robust recipes. So there is a very good chance that you will not notice much of a difference.
If the batter was on the dry side, you might get undissolved sugar. This will give you a grainy texture, possibly you will also perceive the applebread as drier, but the second effect can be subtle. In any case, it will be perfectly edible - it is just that, if the sugar is undissolved, it will deviate from usual expectations. Whether this is a problem or not will depend on the individual eaters.
There will probably be little difference in the final product but as Rumtscho points out, some of the sugar may not dissolve. You might use caster sugar or confectioner's sugar (measure by weight, not volume). Or, grind your sugar in a food processor to get it finer then add it to the mix. Be careful not to over-mix.