UN Secretary General António Guterres, Turkish President Recep Tayyip Erdoğan and representatives from Russia and Ukraine plan to sign an agreement on Friday that is widely hoped would resolve the global grain crisis. The Turkish presidential office’s statement came after a meeting in Istanbul to address the release of grain stuck in Ukrainian ports to prevent a looming hunger crisis in parts of the world most dependent on the supplies. War in Ukraine and the mining of its ports have prevented the export of millions of tons of grain from one of the world’s most important producers. Countries i…