Abstract
Secale L. is a small but important genus that includes cultivated rye. Although genetic diversity of cultivated rye is high, patterns of genetic diversity in the whole genus, and potential factors affecting the distribution of genetic diversity remain elusive. The population structure and distribution of genetic variation within Secale, and its correlation with taxonomic delimitation, cultivation status or spatial distribution in relation to geography and climate zones were analyzed in this study. A collection of 726 individual plants derived from 139 different accessions representing Secale cereale, S. vavilovii, S. strictum, and S. sylvestre were investigated using SSR analysis and sequence diversity analysis of a nuclear EST region. Our results indicated that perennial S. strictum subspecies are genetically divergent from annual forms of the genus. Existence of two distinct clusters within the annual taxa was observed, one corresponding to samples from Asia, and a second to those outside of Asia. No clear genetic structure was observed between different annual species/subspecies, indicating introgression between these taxa. The analysis of cultivated rye revealed that landrace populations from the Middle East have the highest genetic diversity, supporting the idea of the area being the center of origin for cultivated rye. Considering high adaptive potential of those populations, Middle Eastern landraces should be regarded as genetic resources reservoirs for new niches and future breeding programs.
Highlights
Sustainable food production is a vital environmental issue, in the context of global climate change
Genetic allelic patterns were calculated for each group, in the three categories created based on taxonomic identity, cultivation status, and climatic conditions of geographical origin of the samples (Table 2)
The global scale analysis of genetic diversity and phylogenetic relationships of Secale genus show a clear separation between perennial S. strictum subspecies and annual taxa
Summary
Sustainable food production is a vital environmental issue, in the context of global climate change. Elevated temperatures and accompanying alterations in precipitation regimes are expected to decrease yields significantly. Global requirement for food is expected to increase by 60% by 2050. The adaptive capacity of plant populations under stress conditions are positively related to the degree of genetic diversity maintained in those populations [1]. Genetic diversity of modern varieties (cultivars) of crop plants is quite low due to genetic erosion stemming from domestication syndrome and modernization bottlenecks. Wild relatives of crop plants and unimproved varieties known as ‘landraces’ are genetically diverse [2,3] and contain many adaptive alleles in their gene pools
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