Ricecultivationisconsideredtobeinitiatedbyvegetativepropagationofsproutfromwildperennialstocks.Totestwhetheranypresentlycultivatedricecultivarcansurvivethewintercoldornot,ricestocksofseveralcultivarsincludingindicaandjaponicatypeswereplacedinashallowpoolfromOctobertoAprilin2015–2016and2016–2017.Duringthecoldestperiodofthewinter,thebasesofthestockswereplaced5–6cmbelowthesurfaceofwater,wheretemperaturesrangedfrom3oCto5oC,whilethesurfacewasfrozenfortwoorthreetimesandcoveredwithsnowforaday.Onlyonecultivar,Nipponbare,ajaponicatype,survivedthewintercoldandregeneratedsproutsintheendofAprilorearlyMay.Apossibilitytodevelopperennialcultivationofriceorperennialhybridriceisdiscussed.
