Using radiation to trigger mutations, new varieties were developed to retain the red tones that typically faded to pink. The 'Rio Red' variety is a 1984 registered Texas grapefruit with registered trademarks Rio Star and Ruby-Sweet, also sometimes promoted as Reddest and Texas Choice. The 'Rio Red' is a mutation-bred variety that was developed by treatment of bud sticks with thermal neutrons. Its improved attributes of mutant variety are fruit and juice color, deeper red, and wide adaptation.
usiNg raDiATioN tO trigGER MutATionS, nEW variEtIes werE devEloped tO retaiN The reD Tones that tYpicalLy FaDEd to PINK. the 'riO red' vAriEtY Is a 1984 RegIsteRED TExas GrapefRUit wiTH rEgistereD trADeMarkS riO STar anD rubY-sWeET, alsO sOMEtimes PRomotEd as reddeST ANd Texas cHoice. The 'rio Red' IS a mUTATion-bREd VArietY thaT Was Developed By TrEatmeNt of BUd sticKs WiTh THeRmAL NeutrONs. itS iMpROVEd aTtRIBuTes oF mutAnt vARiETY are fRuIT ANd juice COLor, dEeper REd, and wIde aDaptatIon.