Genetic diversity and population structure of Eurasian populations of reed canarygrass: cytotypes, cultivars, and interspecific hybrids

Abstract

Reed canarygrass (Phalaris arundinacea L.) is an important forage crop and potential biofuel feedstock due to its wide environmental adaptation. The P. arundinacea ‘species complex’ is made up of three cytotypes, 2x, 4x, and 6x, with the 4x cytotype (P. arundinacea L.) most common. Active breeding programs have developed cultivars since the early 20th Century, but little is known about the genetics of the species complex. With the aid of DNA markers, we evaluated the population structure of 83 wild accessions collected throughout Eurasia, 24 cultivars, and the genetic relationship between 4x and 6x cytotypes. Seven subpopulations were present in Europe with a high level of admixture, suggesting that reed canarygrass germplasm has spread throughout Eurasia, either naturally or by humans for use in agriculture. Our results indicate that cultivars have incorporated much of the diversity found in wild populations, although modern low-alkaloid cultivars appear to come from a relatively small gene pool. We also found some evidence that the 6x cytotype is made up of three sub-genomes that are a combination of genomes present in 4x P. arundinacea and 4x P. aquatica, although the 6x cytotype does not appear to be a direct hybrid between the species.

Genetic diversity of phalaris arundinacea populations in relation to river regulation in the Merkys basin, Lithuania

“…The highest number of alleles (10–13) was produced by four SSR primers: csm075, csm106 phi071, and umc2185. The number of alleles generated by SSR primer pairs csm074, csm104, csm111, and umc2779 (Table ) was the same as those reported by Jakubowski, Jackson, et al (). For our populations, a slightly lower number of alleles were produced by the two primer pairs, csm045, phi071, and 2‐3× lower number of alleles was obtained with the remainder of eight primer pairs.…”

“…In the present study, P . arundinacea populations differed from previous SSR molecular analyses (Jakubowski, Casler, et al, ; Jakubowski, Jackson, et al, ) as our sampling consisted of higher numbers of individuals in the populations collected in a smaller geographic area and the number of microsatellite primers (14/15) used. Primer pair (umc2272, GCG) which was used for Zea mays (Lawrence et al, ), P. canariensis (Li et al, ) and P .…”

“…The microsatellite (SSR) markers were selected following Lawrence, Dong, Polacco, Seigfried, and Brendel (), Li, Baga, Hucl, and Chibbar (), and Jakubowski, Jackson, et al (). Assessment of 15 oligonucleotide primer pairs resulted in selection of 14 primer pairs for the population analyses (Table ).…”

“…DNA fragments obtained for each SSR loci were scored in a binary format as present (1) or absent (0; Kupcinskiene, Zybartaite, & Paulauskas, ). SSR data were interpreted as dominant markers (Jakubowski, Jackson, et al, ). Analysis of nonhierarchical molecular variance (AMOVA) among and within populations was done using GenAlEx v.6.5 (Peakall & Smouse, ); significance tests were based on 1,000 permutations.…”

“…An advantage of studying P . arundinacea is the large set of molecular markers applied (Anderson et al, ; Barth, Jankowska, Hodkinson, Vellani, & Klaas, ; Bloju, Boldura, Samfira, & Popescu, ; Casler et al, ; Jakubowski, Casler, & Jackson, ; Jakubowski, Jackson, Johnson, Hu, & Casler, ; Jakubowski, Casler, & Jackson, ; Jakubowski, Jackson, & Casler, ; Lavergne & Molofsky, ; Nelson et al, ; Perdereau, Klaas, Barth, & Hodkinson, ), providing tested methodological approaches for further research.…”