He mentions that race doesn't matter; culture matters. They're both intertwined. If you're the product of centuries of inbreeding, like many Muslims in Arabia and Pakistan, then even herculean effort is not going to make you a brain surgeon. In a relatively free and technologically advanced society like the US, the winners and losers will be largely decided on the basis of IQ.
When it comes to races and their average IQs, the following is not surprisingly true: Japanese / Chinese IQ > White IQ > Black IQ