Evaluation of Genetic Diversity and Pedigree within Crapemyrtle Cultivars Using Simple Sequence Repeat Markers

Abstract

<jats:p>Genetic diversity was estimated for 51 <jats:italic>Lagerstroemia indica</jats:italic> L. cultivars, five <jats:italic>Lagerstroemia fauriei</jats:italic> Koehne cultivars, and 37 interspecific hybrids using 78 simple sequence repeat (SSR) markers. SSR loci were highly variable among the cultivars, detecting an average of 6.6 alleles (amplicons) per locus. Each locus detected 13.6 genotypes on average. Cluster analysis identified three main groups that consisted of individual cultivars from <jats:italic>L. indica</jats:italic>, <jats:italic>L. fauriei</jats:italic>, and their interspecific hybrids. However, only 18.1% of the overall variation was the result of differences between these groups, which may be attributable to pedigree-based breeding strategies that use current cultivars as parents for future selections. Clustering within each group generally reflected breeding pedigrees but was not supported by bootstrap replicates. Low statistical support was likely the result of low genetic diversity estimates, which indicated that only 25.5% of the total allele size variation was attributable to differences between the species <jats:italic>L. indica</jats:italic> and <jats:italic>L. fauriei</jats:italic>. Most allele size variation, or 74.5%, was common to <jats:italic>L. indica</jats:italic> and <jats:italic>L. fauriei</jats:italic>. Thus, introgression of other <jats:italic>Lagestroemia</jats:italic> species such as <jats:italic>Lagestroemia limii</jats:italic> Merr. (<jats:italic>L. chekiangensis</jats:italic> Cheng), <jats:italic>Lagestroemia speciosa</jats:italic> (L.) Pers., and <jats:italic>Lagestroemia subcostata</jats:italic> Koehne may significantly expand crapemyrtle breeding programs. This study verified relationships between existing cultivars and identified potentially untapped sources of germplasm.</jats:p>

The first genetic linkage map of crape myrtle (Lagerstroemia) based on amplification fragment length polymorphisms and simple sequence repeats markers

“…A total of 150 SSR primers were synthesized based on published papers (Wang et al. , , Cai et al. , He et al.…”

“…, Wang et al. , He et al. ), which would permit their application as molecular markers in crape myrtle genome mapping.…”

“…Compared with other marker systems, AFLP can be used for linkage mapping with little knowledge of the sequence of the plant in question (Venkateswarlu et al 2006). SSRs have been proven to be effective and highly polymorphic for the evaluation of genetic diversity among Lagerstroemia species and cultivars (Rinehart and Pounders 2010, Cai et al 2011, Wang et al 2011a, He et al 2012, which would permit their application as molecular markers in crape myrtle genome mapping.…”

“…SSR protocol: A total of 150 SSR primers were synthesized based on published papers , 2011a, Cai et al 2011, He et al 2012. These primers were prescreened on two parents and eight randomly selected progeny to identify polymorphisms.…”

Comparative Analysis of Six Lagerstroemia Complete Chloroplast Genomes

“…Due to shared morphological traits to some extent among species and cultivars, the lack of morphological and DNA markers heavily inhibited the genetic diversity evaluation of Lagerstroemia germplasm resources. Genetic information from comparative genomics for researches on genetic diversity and phylogeny in the Lagerstroemia is limited (Pounders et al, 2007; Wang et al, 2011; Suo et al, 2012, 2015, 2016; He et al, 2014; Gu et al, 2016a,b). …”