Analysis Genetic Background To Flower Color Groups In Paeonia Delavayi Franch.

Paeonia delavayi belongs to Paeonia section Moutan DC. in the family Paeoniacene. It is shrub or subshrub, and mainly distributs in Southwest China. Because of the rich variations in flower color, P. delavayi is an excellent wild flower resource with ornamental value and development potential. In order to provide a theoretical basis of breeding strategy and system evolution, the genetic backgrounds of 10 flower color groups were studied from the aspects of morphological characters, palynology characters and EST-SSR molecular marker in this research. The results were shown as follow:(1) The morphological variations were rich in P. delavayi flower color groups. There was no any flower color group in which all the flower characters were in the same color; the green color group was the only group with green stigmas, erect flowers, green filaments and green anthers; the average variation coefficient of 13 quantitative characters of 10 groups ranged from 32.80% to 50.56% indicated that the character stability of individual plant within groups was quite different from each other; the average differentiation coefficient of morphology of 10 flower color groups was 42.25%, the index of quantitative characters of 10 flower color groups was 12.58%, which indicated that the morphological differentiation was distinguished among the different flower color groups.(2) There were a lot of differences in palynological characters among P. delavayi flower color groups. The pollen grain of DS1 and ZH2 flower color groups were sub-speroidal with furrow membrane and tubercles; the types of pollen exine sculpture were anomalous which were in accordance with the results of clustering: most of the pollen grains of LT were foveolate, those of DS1 and DS2 were foreolate-reticulate, and the rest were reticulate.(3) There were corresponding genetic basis in morphological variations of P. delavayi flower color groups. The results of EST-SSR showed that the percentage of polymorphic site was 50.42% with 2-4(2.5) alleles per loci; the genetic diversity (He) was 0.2638, fixation index Fit was 0.7065, and Fis was 0.2990; the gene flow among flower color groups (Nm) was 1.0432, the genetic differentiation among groups (Gst) was 0.4278, and the results of analysis of molecular variance showed that the variances among groups and within groups were 39.19% and 60.81% respectively. It could be concluded that the genetic diversity of P. delavayi flower color group was in middle level; the variation mainly came from intragroup.(4) The P. delavayi flower color groups would be more applicable as the multiple object parents of breeding. The study was comprehensively analyzed from the aspects of morphology, palynology and molecular. The results showed that the genetic differentiations were high among the flower color groups, but the individual genetic polymorphism within the same group was also in high level. Further purification should be made to determine the target characters of breeding parents.