Weird line in my grass textures?

you could try settings your wrap mode in the texture to clamp... and just playing around with the import settings

I've seen artifacts like this (just ran into one today) when the spacing in my Sprite map isn't large enough. If you are using SM2, you can set the distance between your sprites to 4 to see if that resolves it. If you're not using SM2, make sure you have a bit(4px) of trim on each side of your sprite before you import it.

It's mipmapping.

Either turn off mip-mapping on the grass material, or pull the UV's in about 8 pixels from the side of the map.

Remember, mip-mapping halves in size per level, and obviously, as you blur a texture more, artefacts from that will become more noticable :)

All the maps for grass and detail objects are compiled into one map. If you have detail textures without alphas or with all white alphas they'll bleed into your grass textures! If you don't need alphas in your detail textures just go into Photoshop and add a channel in the channels panel and make sure it's black. Turn on all of your channels including the alpha. Your texture should have a red tint to it but don't worry it wont look like that in Unity. Save it as a 32 bit alpha and make sure when you bring it into Unity it interprets it with an alpha. Replace the old texture with the new one in your detail mesh. Once all your detail meshes have alpha, edit one of your detail meshes or grass textures and it should update. Now the lines in the grass textures should be gone!

My solution to that problem:

In photoshop (or the software u use) make sure, that the painted object e.g., grass, is lifted a few pixels upwards from the bottom, also make sure that theres enough room to the other edges.

now export it to Unity.

ATTENTION: U wont see any change in the editor for now, cause u first have to close Unity and reopen it. Voila, the line above ur grass should be gone (at least it worked for me this way)