This doctoral thesis studies the spatial market efficiency of wheat markets in selected post-Soviet countries; particularly in Russia, the largest wheat exporting country in the world, and in the grain import-dependent countries of Central Asia and the South Caucasus. Increased grain production in the Black Sea region, and in Russia specifically, is crucial for meeting increasing global agricultural demand and global food security. Grain production in Russia could be boosted by increasing grain production efficiency and also by re-cultivating formerly abandoned agricultural land. However, to increase Russia's role in global wheat supply, additional grain production potential has to coincide with improving the country's grain export perspectives. On the other hand, the realization of Russia's export capacity largely depends on the performance of its regional grain markets domestically. Using price transmission and panel data analyses in a comparative context, this study finds the wheat market of Russia segmented, with the primary wheat export region poorly integrated into the domestic market. This thesis also demonstrates that regional wheat market integration in Russia is relatively low and heterogeneous and trade costs are relatively high compared to the USA, mostly due to large distances between grain producing regions. In addition, by including the USA as benchmark country, a comparative approach enables a more comprehensive assessment of the spatial market efficiency of the wheat market in Russia. The results also provide evidence on the dissimilarity of the underlying fundamental mechanism of market integration between Russia and the USA. In Russia, the physical trade of wheat mainly fosters market integration at the interregional level, whereas in the USA, in addition to physical trade, information flows induced by commodity futures markets play a major role in the regional grain market integration. (...)