The humble potato has become a factor in Turkey’s political and economic turmoil as prices of the staple soar, hurting the living standards of poorer Turks just before the ruling AK Party’s toughest election test in a decade. At a market in the lower-income Istanbul suburb of Kucukcekmece, potatoes sell for between 3 and 4 lira ($1.33 and $1.77) a kilogram, up from slightly more than 1 lira at about this time last year. More