Life in a cold climate: the adaptation of cereals to new environments and the establishment of agriculture in Europe

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Three geographically separate domestications of Asian rice

Publication . Civáň, Peter; Craig, Hayley; Cox, C. J.; Brown, Terence A.

Domesticated rice (Oryza sativa L.) accompanied the dawn of Asian civilization(1) and has become one of world's staple crops. From archaeological and genetic evidence various contradictory scenarios for the origin of different varieties of cultivated rice have been proposed, the most recent based on a single domestication(2,3). By examining the footprints of selection in the genomes of different cultivated rice types, we show that there were three independent domestications in different parts of Asia. We identify wild populations in southern China and the Yangtze valley as the source of the japonica gene pool, and populations in Indochina and the Brahmaputra valley as the source of the indica gene pool. We reveal a hitherto unrecognized origin for the aus variety in central India or Bangladesh. We also conclude that aromatic rice is a result of a hybridization between japonica and aus, and that the tropical and temperate versions of japonica are later adaptations of one crop. Our conclusions are in accord with archaeological evidence that suggests widespread origins of rice cultivation(1,4). We therefore anticipate that our results will stimulate a more productive collaboration between genetic and archaeological studies of rice domestication, and guide utilization of genetic resources in breeding programmes aimed at crop improvement.

2015-11Journal article

Open access

The evolutionary relationship between bere barley and other types of cultivated barley

Publication . Drosou, Konstantina; Craig, Hayley; Palmer, Karren; Kennedy, Sandra L.; Wishart, John; Oliveira, Hugo R.; Civáň, Peter; Martin, Peter; Brown, Terence A.

We used genotyping-by-sequencing to investigate the evolutionary history of bere, the oldest barley variety still cultivated in Britain and possibly in all of Europe. With a panel of 203 wild and 401 cultivated barley accessions, including 35 samples identified as bere, we obtained filtered datasets comprising up to 1,946,469 single nucleotide polymorphisms (SNPs). The beres formed two genetically-distinct groups, the larger of which included beres from Orkney and the Scottish Western Isles, as well as varieties not identified as bere from the Faroe Islands. This group of beres was distinct from other British barleys, but had a close genetic affiliation with Scandinavian accessions. Although the data were partly compatible with the traditional view that bere was introduced to Scotland by the Vikings during the eighth century AD, the evidence as whole suggested that the bere and Scandinavian barleys are sister groups descended from a more distant common progenitor, possibly dating to the Bronze Age when hulled barleys first become common in northern Europe. More recently, there has been gene flow from these beres into Polish barleys, possibly following export of grain to the Baltic region during periods when Orkney was under Norwegian or Danish rule. A second, smaller group of beres, which included a traditional Welsh variety, was genetically distinct from the main group and probably represents a more recent introduction of barley from central Europe. Our results emphasize the uniqueness of bere barley and its importance as a heritage crop and a potential source of germplasm for breeding programmes.

2022Journal article

Open access

A discriminatory test for the wheat B and G genomes reveals misclassified accessions of Triticum timopheevii and Triticum turgidum

Publication . Czajkowska, Beata Izabela; Oliveira, Hugo R.; Brown, Terence A.

The tetraploid wheat species Triticum turgidum and Triticum timopheevii are morphologically similar, and misidentification of material collected from the wild is possible. We compared published sequences for the Ppd-A1, Ppd-B1 and Ppd-G1 genes from multiple accessions of T. turgidum and T. timopheevii and devised a set of four polymerase chain reactions (PCRs), two specific for Ppd-B1 and two for Ppd-G1. We used these PCRs with 51 accessions of T. timopheevii and 20 of T. turgidum. Sixty of these accessions gave PCR products consistent with their taxon identifications, but the other eleven accessions gave anomalous results: ten accessions that were classified as T. turgidum were identified as T. timopheevii by the PCRs, and one T. timopheevii accession was typed as T. turgidum. We believe that these anomalies are not due to errors in the PCR tests because the results agree with a more comprehensive analysis of genome-wide single nucleotide polymorphisms, which similarly suggest that these eleven accessions have been misclassified. Our results therefore show that the accepted morphological tests for discrimination between T. turgidum and T. timopheevii might not be entirely robust, but that species identification can be made cheaply and quickly by PCRs directed at the Ppd-1 gene.

2019-04Journal article

Open access