A&I 1-48

Ruby Red nucellar budwood was irradiated in 1963, and the darker A&I 1-48 selection was found in 1971. It was not commercially released; Rouse et al. report the selection's budded trees were planted in a comparison trial that year.^⁠[1]⁠[3]

Rouse et al. report that a bud sport on A&I 1-48 was found in 1976 and introduced as Rio Red in 1984. The 2020 chapter gives conflicting discovery years (1976 in the narrative and 1978 in its cultivar profile). The 2021 review describes A&I 1-48 fruit as having about three times the red color intensity of original Ruby Red and assigns the fivefold red-color comparison to the later Rio Red bud sport.^{⁠[3]⁠[2]⁠[5]}