Genetic diversity analysis of intraspecific hybridization between Plumbago auriculata and Plumbago auriculata f. alba based on horticultural traits and molecular markers

Abstract

Plumbago auriculata Lam. is an ornamental plant native to South Africa and widely cultivated in China, but the cultivated plants are dominated by a single variety. The development of new varieties is of great commercial interest, and genetic diversity is the foundation of breeding programs. In this study, 85 progenies were obtained by crosses between Plumbago auriculata and Plumbago auriculata f. alba. The genetic diversity of these hybrids was evaluated using horticultural traits and ISSR and SRAP markers. Of the 25 horticultural traits evaluated, the largest variation was found in the beginning of the blooming period, and sepal length was the least variable trait. Correlation analysis showed that the wider the plant, the greater the number of inflorescences and the earlier the flowering. Seven factors explained 65.171% of the total variance; the first factor was leaf morphology, and the second factor was flower morphology. The genetic diversity of the 85 progenies was analyzed using seven pairs of SRAP primers and eight ISSR primers. The average number of effective alleles for 85 hybrids was 1.638, and the average Shannon index value was 0.507. The Nei genetic similarity coefficient indicated that the similarity between WLBS and WSBL was the highest, while that between BLWS and BSWL was the lowest. Analysis of molecular variance (AMOVA) indicated that the main variation was within populations. Cluster analysis based on horticultural traits and molecular markers divided all progenies into seven and five groups, respectively, and there were obvious differences between the two clusters. In this study, we created intermediate materials for future breeding, taking the first step in the cross-breeding of P. auriculata.