Furthermore, although the Korean route was traditionally regarded as a likely introduction route for rice, the theory stating that rice-paddy plants were introduced through the direct introduction route from the continent (Tsushima Warm Current route/Southern introduction route from South East Asia) is now regarded as very likely from the several facts that remains of rice-paddy fields were not discovered in the Liaodong Peninsula and northern Korea until sites of modern times, the oldest carbonated rice found in the Korean Peninsula only goes back to 2000 B.C., the only a rice plants grown in a dry field were confirmed from that time, and genetic analysis of temperate Japonica rice (a rice-paddy plant)/tropical Japonica rice (a rice plant grown in a dry field) in Far East Asia shows no evidence of concerned genes from Korean Peninsula nor from North East China (Contrary to traditional theory, there is a possibility that rice-paddy plants had been introduced into Korean Peninsula from Japan.)
また、イネの伝来ルートについても従来は朝鮮ルートが有力視されていたが、遼東半島や朝鮮北部での水耕田跡が近代まで見つからないこと、朝鮮半島での確認された炭化米が紀元前2000年が最古であり畑作米の確認しか取れない点、極東アジアにおける温帯ジャポニカ種（水稲）/熱帯ジャポニカ種（陸稲）の遺伝分析において、朝鮮半島を含む中国東北部から当該遺伝子の存在が確認されないことなどの複数の証左から、水稲は大陸からの直接伝来ルート（対馬暖流ルート・東南アジアから南方伝来ルート等）による伝来である学説が有力視されつつある（従来の説とは逆に水稲は日本から朝鮮半島へ伝わった可能性も考えられている）。