Abstract:

SSR and SRAP markers and morphological traits were used to analyse the genetic diversity of the interspecific F1 population derived from the cross between diploid Chrysanthemum related species C. nankingense and C. lavandulifolium. The results showed that 122 of 131 F1 hybrids were true hybrids，and the true hybrids rate was 93.13%. Forty-two SSR primer combinations amplified 123 polymorphic bands in C. nankingense，C. lavandulifolium and 122 F1 hybrids，with an average of 3 polymorphic bands per primer combination. Eighteen SRAP primer combinations amplified 55 polymorphic bands，with an average of 3 polymorphic bands per primer combination. The genetic similarity coefficients between the interspecific hybrids of C. nankingense × C. lavandulifolium were between 0.44 and 0.90，and the phenotypic variation coefficients of interspecific hybrids were between 10.16% and 16.67%. Some transgressive individuals were observed，indicating an abundant genetic variation in the interspecific F1 population. In addition，it was observed that the interspecific hybrids segregated towards the female parent in leaf morphology. UPGMA cluster analysis based on phenotypic traits and molecular markers both classified parents and 122 hybrid progenies into 7 groups. Most of the hybrid progenies were clustered together with the female parent（C. nankingense），while the male parent（C. lavandulifolium）and a few hybrid lines were clustered separately. The clustering results showed that the F1 hybrids were more similar to the female parent. The average coefficient of genetic similarity（0.62）between female and interspecific hybrids was higher than that of male parent（0.54）. This indicates that the interspecific hybrids are closer to female parent in heredity，consistent with the results of morphological analysis.

Key words: Chrysanthemum related species, C. nankingense, C. lavandulifolium, interspecific hybridization, hybrid identification, molecular marker, genetic diversity