* Armenian Genocide (1915-1923)
* Greek Genocide (1914-1923)
* Assyrian Genocide (1914-1925)
These groups were targeted because they were Christian, not because they were white. I'm not aware that any Greek-speaking Muslims were persecuted by the Ottomans.
The Young Turk government considered the Armenians, the Greeks and the Assyrians as enemies of state, regardless of their religion or their allegiance to the Turkish government. This was because the fear that those ethnicites would welcome liberation by their enemies during the slow collapse of the Ottoman Empire. Deep-seated hatred of the AGA (Armenian, Greek, Assyrian) rooted since the conquests of the Ottoman Empire.
* The Holodomor (1932-1933)
Was the result of Soviet policy, but was not an attempt to wipe out an ethnic group. Even if it were, it wouldn't count as Ukrainians weren't targeted for their whiteness.
Joseph Stalin wanted to annihilate any nationalist, ethnic and anti-Communist movements that occurred in Ukraine as well with the anti-Ukrainian sentiment of the Soviet era. Stalin engineered the famine to kill thousands of Ukrainian peasants, ordered Red Army troopers to shoot at desperate food thieves, deliberately refused food aid from international organizations, restricted population movement and foodstuff raiding from peasants' food supplies.
* Ottoman rule in the Balkan
While Christians were persecuted, I'm not aware of anyone being persecuted for being white. Certainly Greek or Bulgarian speaking Muslims were not persecuted.
The Ottomans punished Muslim Bulgarians who considered themselves more Bulgarian than Turk and bothered to stand up against Ottoman repressions of the Balkan peoples. The Ottomans also engaged in enslavement of Balkan peoples by forcing children into Janissary corps or slave raids. Many European women were forced into Ottoman or Tartar harems. The slave trade of the European people was considered a normal and legal part of the Empire's economy.
In the Balkans, many Europeans had to give children due to the devsirme, which meant "blood tax" or "child collection" or children abducted by the Ottoman soldiers. Massacres and mass violations against women by the Ottoman soldiers were common for Balkan people who refused to engage in the practice or rebelled against authority.