I 'll be repeating myself now, but I think we use too easily the word "genetic".
If I use a sample of people of different races and have them take an IQ test, whatever difference should I find, I cannot interpret the result as being "genetic". The IQ test is a very un-scientific tool to prove anything and, as toonia said, it is culturally biased.
Genetic characteristics are characteristics that correspond to an identified gene or genetic mechanism. And up to now, there are not convincing studies of genes related with intelligence.
And one more thing: it is not proved that there genetic differences between races, or the various races would have been called sub-species. Human beings of all races have very similar genetic structures, and the differences between them are mostly phenotypical