I know that there are some of these intervals on a single row, but not enough to play complete harmonized melodies in the same way as on a triple row (or a piano accordion or CBA for that matter). On a triple row, you can harmonize every single note. On a single row, there are many notes for which that is impossible. I would need to have my accordion to verify this precisely, but I am thinking that more than half of the harmonized scale is missing on a single row.

How much is lost by that is a subjective question. One could just harmonize the notes for which it was possible and just play the melody note for the rest. Whether that would sound OK or not is up to the listener, I suppose. My opinion is that it wouldn't sound right, but that is merely my opinion.

But it begs the question of why bother doing that in the first place? Why go to heroic lengths to fit a style of music to an instrument that is unsuited for it? I guess if you don't have a triple row, then it is necessary to resort to such things. But if you have a triple row, why bother? My feeling is that this is a case of using the appropriate tool for the job. For example, a cross cut saw and a coping saw are both saws, and they will both cut wood. But, they each have their uses for which they are better suited than the other. It doesn't mean that one is better than the other or anything like that. A skilled wood worker would have one of each, and use them appropriately.

-David

A skilled, professional woodworker, that is...
not the weekend warrior woodworker hobbyist. And there is a BIG difference in the price of a coping saw and an accordion!

The original question was of the POSSIBILITY...not PRACTICALITY. The original poster got the answer he was looking for, "yes, you can play a little tex-mex sounding stuff on your one row for variety's sake in a gig without buying a whole new box for one or two songs." He listened to the recordings I referenced and liked what he heard and was satisfied.

You are right you can not do EVERY third like on a triple row, but by "mixing" the thirds and sixths I posted you can sound pretty dang convincing on a very simple song in the key of the box. I played in TX with Kingfish when I was kind of dabbling with the tex mex sound in our music--but I did not have a triple row. A triple row player in the audience asked to see my accordion...he asked "Where's the other buttons? You're making all that noise with one row?!" He said, "It is much easier with more rows!"

Since a friend loaned me a triple row, I can see how right he was. But the triple row is a monster in many ways because you can play the same notes in so many different ways!

I would not start a Tex Mex band with only a single row accordion, don't think I would get very far! What I was trying to say or to demonstrate is possiblities of playing a tune on the single row that suggests a tex mex sound or style.

Let me know if you find the time to try out all the intervals I demonstrated. I think it is "cool" because it might inspire someone to come up with some new licks for Cajun tunes!