Genetic diversity of three Israeli wild relatives of wheat from the Sitopsis section of Aegilops

Israel is rich in wheat wild relatives. Some of the species have a restricted geographic distribution, grow in small populations, and are subjected to habitat fragmentation. To better conserve and exploit these species there is a need to characterize the genetic structure of ex situ collections. The population structure and genetic diversity of three wheat wild relatives from the genus Aegilops were studied. Collections of the species Ae. longissima (23 accessions), Ae. sharonensis (105 accessions) and Ae. speltoides (157 accessions) from the Institute for Cereal Crops Improvement (ICCI), Tel-Aviv University were genotyped using genotyping by sequencing (GBS) technique. Principal Component Analysis (PCA) revealed different and similar diversity patterns among the species. All species had differences between northern and southern populations, however, in Ae. sharonensis there was a more significant component differentiating western and eastern populations. Some of the southeast accessions of Ae. sharonensis clustered together with the northern - coastal Ae. longissima accessions away from the rest of the Ae. longissima and Ae. sharonensis accessions. Ae. sharonensis collection has shown much more population differentiation than Ae. speltoides collection while in Ae. speltoides the total genetic diversity within populations diversity was higher. Ae. sharonensis population structure was more correlated with geographic distance while Ae. speltoides population structure has shown less structured populations and less correlation with geographic distance. Ae. sharonensis population structure was also correlated with soil type and humidity while in Ae. speltoides northern collection no correlation with the environment was found. The evolutionary and conservation perspectives of these finding are discussed.