I'll load it up and try again.
Just tested. Berry bushes drop berries.
Edited to add: If you loaded the world once with several mods disabled and then moved gregtech into it, it might rearrange id's from mods that weren't present and that might cause a conflict.
Instead try
1. Launch the game with all mods enabled.
2. Close the game without making a world.
3. Place Gregtech in the pack
4. Launch the game
5. Close the game without making a world.
6. Disable the mods you don't want
7. Launch and create a world.
8. Play
Just tested. Berry bushes drop berries.
Edited to add: If you loaded the world once with several mods disabled and then moved gregtech into it, it might rearrange id's from mods that weren't present and that might cause a conflict.
Instead try
1. Launch the game with all mods enabled.
2. Close the game without making a world.
3. Place Gregtech in the pack
4. Launch the game
5. Close the game without making a world.
6. Disable the mods you don't want
7. Launch and create a world.
8. Play