I think that there is a typo in the line and it should be 才能の有無があるなら多分そういう事だろう, however, in either case I am not quite sure what is being said. Here's the exchange for context:
わ、私だって努力してるのよ！でも…アンタ達みたいに才能ないから
努力は創意工夫だ。ただやればいいってもんじゃない。才能に有無があるなら多分そういう事だろう。
This is a reference to so-called 正しく努力する才能 ("talent to make a correct effort"). そういう事 refers to what he just said (努力は創意工夫だ。ただやればいいってもんじゃない).
才能に有無があるなら多分そういう事だろう。
If there is a distinction between "talented" and "no talent", it probably amounts to such a fact.
(Free translation) If there is something called a talent, that's about understanding how to make an effort effectively.
So the guy is saying that 私だって努力してる is not an excuse because improper 努力 is meaningless. The guy is also implying a right effort comes with a good result.
EDIT: 才能に有無がある is not a typo, and this に is just an (abstract) location marker used with ある/いる/etc. A very literal translation is "If there is (a distinction between) presence and absence in talent".
