Identification and evaluation of F₁ hybrids between Rosa ‘Sanka’×R. multiflora var. cathayensis

ObjectiveIn this study, we used modern rose cultivars ‘Sanka’ (2n = 4x = 28) and R. multiflora var. cathayensis (2n = 2x = 14) as parents to obtain F₁ population through hybridization, and the hybrids were identified and evaluated. This will provide an important basis for improving the modern rose by R. multiflora var. cathayensis.

MethodWe obtained 91 F₁ hybrids derived from the combination of R. ‘Sanka’ × R. multiflora var. cathayensis. The hybrids were identified by morphological observation, flow cytometry, karyotype analysis and SSR markers.

ResultThe results showed that, F₁ hybrids integrated the morphological characteristics of both ‘Sanka’ and R. multiflora var. cathayensis, and the coefficient of variation ranged from 19.71% to 67.13%. Flow cytometry analysis showed that the 70 of the 91 hybrids were triploids (2n = 3x = 21), 18 were tetraploid, 1 was hexaploid (2n = 6x = 42), and 2 unable to be determined. Karyotype analysis of 21 non-triploid identified by flow cytometry analysis and 3 triploid hybrids of continuous flowering revealed that the chromosome number of 18 hybrids were consistent with the results of flow cytometry analysis. The accuracy of flow cytometry for measuring ploidy was 93.41%. From 26 pairs of SSR primers, 7 pairs of polymorphic primers were selected to amplify 2 tetraploids and 1 hexaploid, and found that the two tetraploid hybrids were false hybrids, and the hexaploid were true hybrids.

ConclusionKaryotype analysis and SSR analysis were more accurate than morphological observation and flow cytometry to identify hybrids. The results provide important basis for rose polyploidy breeding, and provide new germplasm materials for the improvement of modern rose using R. multiflora var. cathayensis.