Species Relationships in the Genus Agrostis Based on Flow Cytometry and MITE‐Display Molecular Markers

Abstract

It is estimated that there are between 150 and 200 species of Agrostis, and interspecific hybridization is a proven method for improving cultivated Agrostis species. The pool of publicly available Agrostis germplasm, available through the National Plant Germplasm System, represents 17% of the total number of Agrostis species. The total amount of genetic diversity of this germplasm should be assessed to determine if there are novel sources of stress resistance. Agrostis species have a base haploid chromosome number of seven and can range in ploidy from diploid (2n = 2x = 14) to dodecaploid (2n = 12x =: 84)

Evaluation of Population Structure within Diploid Agrostis Germplasm Based on Miniature Inverted‐Repeat Transposable Elements

“…Vergara and Bughrara (2003)hypothesize that A. transcaspica may be the source of the A 3 subgenome of A. stolonifera , and this finding was later supported by Reichman et al (2011). The DNA content of the A. transcaspica accession was reported by Amundsen and Warnke (2011); however, the DNA content of A. transcaspica was consistent with the tetraploid accessions in their study. The source of A. transcaspica used in each of these studies was the same (NPGS, PI 283174), and contamination of the seed lot could explain these inconsistencies in the data.…”

“…Both chromosome counts and flow cytometry have been used to predict the ploidy level of Agrostis (Arumuganathan et al, 1999Arumuganathan and Earle, 1991Bonos et al, 2002Hollman et al, 2005). Amundsen and Warnke (2011)were less successful at delineating Agrostis accessions into ploidy groups based on flow cytometry DNA content measures. Vergara and Bughrara (2003)used meiotic cell chromosome counts to determine the ploidy level of the accessions used in their study.…”

“…Agrostis species (bentgrasses) have considerable cold hardiness but are susceptible to a number of diseases and would benefit from enhanced heat and drought tolerance. Diploid germplasm generally houses the vast majority of genetic variation and therefore wild diploid Agrostis germplasm is a potential source of novel stress tolerance (Amundsen and Warnke, 2011). Gaining an understanding of the amount of genetic diversity in publicly available Agrostis germplasm sources and how this material relates to cultivated species would greatly benefit strategies used in Agrostis improvement.…”

“…In a recent study by Amundsen and Warnke (2011), miniature inverted‐repeat transposable element (MITE)‐display molecular markers proved to be a valuable tool for studying Agrostis species relationships. Understanding the evolutionary relationships in Agrostis is challenging because most Agrostis species are highly outcrossing tetraploids and interspecific hybridization is common.…”

“…By studying the genetic diversity and species relationships of diploid germplasm and the extent of genetic similarity with higher ploidy cultivars, we hope to determine the usefulness of the diploid germplasm collections. This study is designed to use the MITE‐display techniques described by Amundsen and Warnke (2011) to characterize the level of genetic diversity among known Agrostis diploids and to determine which accessions are most closely related to cultivated A. stolonifera . Furthermore, an understanding of the genetic diversity among diploid Agrostis accessions will allow for recommendations on how best to maintain germplasm resources.…”