Genetic identity and diversity among experimental selections and cultivars of vegetatively propagated turf bermudagrass as assessed with SSR markers

Abstract

Turf bermudagrass (Cynodon spp.) is the most common, warm-season, sod-forming perennial grass for residential lawns, sports fields, golf courses, and public landscapes in warm climates across the world. Genetic diversity and identity information are important for breeding new cultivars and production certification. Accordingly, this experiment was designed to genotype experimental selections along with commercial cultivars to analyze their genetic diversity. Nineteen advanced selections from the Oklahoma State University (OSU) turfgrass breeding program and 13 cultivars were used in the genetic analysis. Fifty-four simple sequence repeat (SSR) primer pairs (PPs) selected across the bermudagrass genome produced 618 polymorphic PCR fragments, of which 120 fragments amplified by using 48 SSRs were unique to the 19 experimental selections. Genetic similarity coefficients varied from 0.69 to 1.00. The AMOVA results indicated 94% of the variation resided within the selections or cultivars. The UPGMA analysis showed that groupings were associated with origins of their parental germplasm. The seventeen distinct experimental selections identified were genetically different from all commercial cultivars tested, demonstrating the potential of adding genetic diversity to the existing cultivar pool if one or more of the experimental genotypes are released for commercial production.

Directional Breeding Generates Distinct Genetic Diversity in Hybrid Turf Bermudagrass as Probed with Simple Sequence Repeat Markers

“…A genetic differentiation analysis of 55 wild accessions of bermudagrass using SSR markers also reported that approximately 30% was attributed to among-group variations and approximately 70% was attributed to within-group variations (Ling et al 2012). Our results are in agreement with those of previous studies of different sets of bermudagrass genotypes (Godwin et al 2022). The higher frequency of within-group variations than that of among-group variations demonstrates the high heterozygosity attributable to the outcrossing nature of bermudagrass.…”

“…The SSR markers showed a high level of polymorphism among bermudagrass accessions and is touted as a reproducible marker system for genetic analyses (Godwin et al 2022;Wang et al 2013), varietal identification or certification and genetic diversity analyses (Fang et al 2015(Fang et al , 2017Godwin et al 2022;Yang et al 2018), and trait associations (Fan et al 2020;Xie et al 2015). The SSR markers (also called microsatellites) are ubiquitous in the genome of different higher plant species with high polymorphism, length variations, and codominant Mendelian inheritance (Morgante and Olivieri 1993;Saghai Maroof et al 1994).…”

“…The Oklahoma State University (OSU) turfgrass breeding program has been at the forefront of developing new genotypes with enhanced traits. These experimental genotypes have undergone multienvironment field trials to assess turfgrass quality, winter survivability, and drought resistance (Godwin et al 2022). Through careful evaluation, elite selections have been chosen for patent applications and commercial release, greatly enhancing the aesthetic value and stress tolerance of these cultivars.…”

“…The OSU has been conducting two directional breeding efforts: one for cold-hardy cultivar development and the other for drought-resistant cultivars. The research performed at OSU included characterizing the genetic diversity of new turf bermudagrass experimental selections and comparing them to standard cultivars using SSR markers (Godwin et al 2022). By using this directional breeding technique, we were able to determine which cultivars may be more adaptable to colder climates or require less irrigation water in drought-prone areas.…”