Floriculture and Ornamental Biotechnology (2009)
The Inheritance of Juvenile Recurrence in Rosa Species Hybrids
Roger E. Mitchell II*

... in diploid crosses of R. wichurana [sic] and a hybrid China rose ('Old Blush'), Shupert and Byrne (2007) saw greatly reduced ratios of recurrent to non-recurrent offspring. Svejda (1976) also saw low percentages of recurrence in diploid crosses of recurrent hybrid China rose cultivars with selected forms of the recurrent species R. rugosa Thunb. ex. Murray. In this case, only 28% of the offspring were recurrent, much lower than the 100% predicted by the single-locus theory. Taken collectively, these studies indicate that the single-locus, r/R theory, while generally accurate, can be complicated by other factors.