''Rosa'' × ''kordesii'', or ''Rosa kordesii'', is a red type of

rose A rose is either a woody perennial plant, perennial flowering plant of the genus ''Rosa'' (), in the family Rosaceae (), or the flower it bears. There are over three hundred Rose species, species and Garden roses, tens of thousands of cultivar ...

that arose naturally from hybridization followed by chromosome doubling. A hybrid between ''R. rugosa'' and ''R. lucieae'' was created called ''Rosa'' 'Max Graf', but it was

diploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Here ''sets of chromosomes'' refers to the number of maternal and paternal chromosome copies, ...

and nearly sterile, producing flowers but no fruit. This rose produced a few viable seeds as a result of self-pollination, and the seedlings that resulted were tetraploid instead of diploid, i.e., the chromosomes of both pollen and

egg cell The egg cell or ovum (: ova) is the female Reproduction, reproductive cell, or gamete, in most anisogamous organisms (organisms that reproduce sexually with a larger, female gamete and a smaller, male one). The term is used when the female game ...

s had been naturally duplicated. The tetraploid seedlings are

amphidiploid Polyploidy is a condition in which the cells of an organism have more than two paired sets of ( homologous) chromosomes. Most species whose cells have nuclei (eukaryotes) are diploid, meaning they have two complete sets of chromosomes, one fro ...

s. page 176 A selection with double deep pink flowers and repeat bloom, also called 'K01 AgCan' was released by W. Kordes' Söhne in 1951. These tetraploid roses interbreed readily with one another, but not with their diploid ancestors. Under the

biological species concept A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of classification and ...

, a new species name ''Rosa × kordesii'' was created for the tetraploid hybrid roses and their descendants. Amphidiploid roses can also be created deliberately from diploid-diploid hybrids by using

colchicine Colchicine is a medication used to prevent and treat gout, to treat familial Mediterranean fever and Behçet's disease, and to reduce the risk of myocardial infarction. The American College of Rheumatology recommends colchicine, nonstero ...

spray on the growing tips of the plants. That strategy gives few successes, however, because the plant tissue has various chromosome numbers in different cells. Amphidiploid roses including ''Rosa × kordesii'' have been used to some degree in breeding programs in combination with naturally occurring tetraploid roses.

Uses

''Rosa'' × ''kordesii'' petal extract gel is stable for at least 3–4 months when stored at 5 and 25 °C. It is essential for collection of similar data for different plants and their flowers, as well as other parts. This proved activity of plant showed its importance and prophylactic utility in anti-solar formulation. This will be a better, cheaper and safe alternative to harmful chemical sunscreens that used nowadays in the industry.

References

kordesii {{Rosa-stub