OOC: Yes, completely. Its not always true, but it shows a lot.
During the Napoleonic wars for example, Prussian skirmishers were a lot worse than their French counterparts as a general rule, due to the differences in culture, society and general thinking at the time. The Prussians weren't used to acting on their own intiative.
The same goes for morale. Russian soldiers for example, could be relied upon to stand and fight in pretty much any circumstance, due to strict discipline and cultural issues.
If you bring someone up to respect authority, then they are more likely to obey it. If someone is heavily influenced by the ideas of independent thought and initiative, then they will be more inclined to use that.
Its not from the genetics of the nationality (With a few exceptions, such as the Gurhkas), but from the values of that nation.
Fry, give me 5 mins and Ill send some.