Population structure in landrace barley (Hordeum vulgare L.) during the late 19th century crop failures in Fennoscandia

Abstract

Agricultural disasters and the subsequent need for supply of relief seed can be expected to influence the genetic composition of crop plant populations. The consequences of disasters and seed relief have, however, rarely been studied since specimens sampled before the events are seldomly available. A series of crop failures struck northern Fennoscandia (Norway, Sweden and Finland) during the second half of the 19th century. In order to assess population genetic dynamics of landrace barley (Hordeum vulgare), and consequences of crop failure and possible seed relief during this time period, we genotyped seeds from 16 historical accessions originating from two time periods spanning the period of repeated crop failure. Reliable identification of genetic structuring is highly dependent on sampling regimes and detecting fine-scale geographic or temporal differentiation requires large sample sizes. The robustness of the results under different sampling regimes was evaluated by analyzing subsets of the data and an artificially pooled dataset. The results led to the conclusion that six individuals per accession were insufficient for reliable detection of the observed genetic structure. We found that population structure among the data was best explained by collection year of accessions, rather than geographic origin. The correlation with collection year indicated a change in genetic composition of landrace barley in the area after repeated crop failures, likely a consequence of introgression of relief seed in local populations. Identical genotypes were found to be shared among some accessions, suggesting founder effects and local seed exchange along known routes for trade and cultural exchange.

POPULATION STRUCTURE AND LINKAGE DISEQUILIBRIUM ANALYSES OF MODEL PLANT Brachypodium distachion THROUGH iPBS MARKERS

“…A considerable amount of natural diversity was also observed in the wild grass BD according to a phenotypic characterisation study (Tyler et al, 2014). In previous studies, the Fst values were detected as 0.36 in barley (Forsberg et al, 2019), 0.18 in durum wheat (Maccaferri et al, 2005) and 0.85 in rice (Garris et al, 2003). The differences in the genetic variation levels between these close grain species may be due to differences in their breeding history and cultivation rates in the habitats of the genotypes (Casler, 2012).…”

Characterization of the complete chloroplast genome of Hordeum vulgare L. var. trifurcatum with phylogenetic analysis

“…The genus Hordeum comprises more than 30 species. Some varieties are also found in this genus (Malysheva-Otto et al 2006;Forsberg et al 2019;Hagenblad and Morales 2020;Kumar et al 2020). Organelle genomes have been widely used in study of taxonomy, evolution and genetics (Wang et al 2016;Yang et al 2019;Wang et al 2020;Li, He, et al 2020).…”

Genetic Diversity in 19th Century Barley (Hordeum vulgare) Reflects Differing Agricultural Practices and Seed Trade in Jämtland, Sweden

“…To situate the data produced in this study in a Scandinavian context, already available genotyping data for Swedish and Norwegian landrace barley for the same SNPs [6,19] were re-analyzed. In addition, unpublished data from two already genotyped Norwegian accessions were added, the extant accessions NGB456 ('Dønnes') and NGB2079 ('Skjåk') and the accession "Sjønstå1" consisting of two grains found during the restoration of the roof to an old building at Sjønstå farm, Fauske, Nordland (Hanne Prytz, pers.…”

“…Fortunately, several historical collections exist, containing 19th century seed of landrace cereals from the Scandinavian peninsula (Norway and Sweden) [15][16][17]. Molecular genetic studies have shown that DNA can be extracted from the grains in these collections [15] and that the samples can be used to infer the role of natural selection for local adaptation [18] as well as the evolutionary consequences of historical events such as trade and crop failure [14,19].…”

“…Due to the short growth season in the region, not all years resulted in a ripe harvest and during the 19th century crop failures are known to have occurred in 1800, 1808, 1821, 1830-1833 and 1867 [32,38]. Such crop failure events have been shown to result in change in the genetic composition of cultivated crops due to an influx of replacement seed [19]. To what extent replacement crop in Jämtland was sourced from Trøndelag, neighbouring Swedish counties, or locally, is not known.…”