Assessment of genetic diversity and identification of core germplasm in single-flowered amaryllis (Hippeastrum hybridum) using SRAP markers

Abstract

Selection for new single-flowered amaryllis with cultivated wild species or hybrids has continued for more than 200 years. However, our basic knowledge of the extent of genetic variation within the single-flowered amaryllis is still not sufficient, which is very important for the ongoing improvement of the double-flower type in China. In this study, a total of 23 screened sequence-related amplified polymorphism (SRAP) markers were used to assess the genetic diversity and population structure of 82 cultivated accessions. It produced 244 clearly amplified fragments, of which 242 (99.2%) were polymorphic. A higher level of genetic diversity was observed, with estimates of Nei’s diversity index (H) and the Shannon information index (I) of 0.344 and 0.513, respectively. Genetic distance- and structure-based analyses mainly clustered all accessions into two or five subgroups, indicating the complexity of the hybrid pedigree of single-flowered amaryllis. To effectively explore and preserve the novel variation in these 82 genetic resources, we further established an initial core collection with 15 accessions with the goal of maximizing the SRAP alleles. This preliminary core set retained 100% of the SRAP variation with greater genetic diversity and heterogeneity (H = 0.355, and I = 0.529). Our research provided insight into the genetic structure of modern hybrids of single-flowered amaryllis, from which an easily manageable amaryllis core collection was identified, facilitating future breeding progress for double-flowered amaryllis.