"Another plant at Moose Range which I was able to save at that time or thereabout was the Yellow Altai rose, sister of Hazeldean. It is a single, with a rather small flower, bright yellow when it first opens, but fading rather rapidly. It is less hardy than Hazeldean, but hardier than Harison's Yellow, and grows more finely branched. It is very fertile, and set many heps, which, however, are much smaller than the less numerous heps of Hazeldean, and with much smaller seeds. If it were pollinated by Hazeldean, or vice-versa, I'd get the F2 of the Altaica x Persian Yellow cross, which might have a considerable proportion of segregates susceptible to blackspot, but should be most interesting nevertheless. Unfortunately, seeds of Yellow Altai do not germinate easily.

Percy Wright Autobiography Volume II page 476

[Percy and Bert Porter drove to Moose Range, the location of Percy's old nursery in the spring of 1959 to collect plant material to be transferred to Bert's property at Parkside, Saskatchewan]

"Yellow Altai - R. spinosissima x Harison's yellow
Height 6 feet, very hardy. Smallish, single, medium yellow flowers, sometimes producing heavily enough to cover the bush. Blooms once, sets seed freely."
Walter Schowalter notes 1985

The correct parentage of 'Yellow Altai' is Rosa spinosissima altaica x 'Harison's Yellow'. It is a sister
seedling of 'Hazeldean'. Percy Wright wrote many articles on his Altai rose breeding and always referred to 'Harison's Yellow' as the staminate parent. Another sister seedling of 'Hazeldean' is 'Kilwinning' (double white flowers with a slight yellow centre) and was introduced in 1967. All three cultivars are still in existence.