Fagus L. is a key component in temperate deciduous broadleaf forests of the Northern Hemisphere. However, its biogeographic history has not been examined under the framework of a fully resolved and reasonably timecalibrated phylogeny. In this study, we sequenced 28 nuclear single/low-copy loci (18 555 bp in total) of 11 Fagus species/ segregates and seven outgroups. Phylogenetic trees were reconstructed using both concatenation-based (maximum parsimony, maximum likelihood, and Bayesian inference) and coalescent-based methods (StarBEAST2, ASTRAL). The monophyly of two subgenera (Fagus and Engleriana) and most sections was well supported, except for sect. Lucida, which was paraphyletic with respect to sect. Longipetiolata. We also found a major phylogenetic conflict among North American, East Asian, and West Eurasian lineages of subgen. Fagus. Three segregates that have isolated distribution (F. mexicana, F. multinervis, and F. orientalis) were independent evolutionary units. Biogeographic analysis with fossils suggested that Fagus could have originated in the North Pacific region in late early Eocene. Major diversifications coincided with a climate aberration at the Eocene/Oligocene boundary and the global cooling since mid-Miocene. The late Miocene accelerated global cooling and the Pleistocene glaciations would have driven beeches into East Asia, North America, and West Eurasia. Meanwhile, range reduction and extinction in high latitudes, central Asia, and western North America converged to form the beech modern distribution pattern. This study provides a first attempt to disentangle the biogeographic history of beeches in the context of a nearly resolved and time-calibrated phylogeny, which could shed new insights into the formation of the temperate biome in the Northern Hemisphere.

Saffron (Crocus L.) is a member of Crocoideae, the biggest of four subfamilies in the Iridaceae family. It has 2n = 3x = 24 chromosomes and is triploid; thus, it is sterile. In previous research, different molecular DNA markers were used but molecular characterization and genetic diversity of this complex genus have not yet been clarified. Therefore, current study aimed to determine the molecular characterization of saffron and its close relative species using inter-primer binding site (iPBS)-retrotransposon markers. Eighty-three iPBSretrotransposon primers were used in 28 C. sativus genotypes and 17 close relative species of saffron to identify their genetic diversity. Sixteen polymorphic iPBS-retrotransposon primers generated a total of 401 polymorphic scorable bands. The mean PIC value, Nei's genetic diversity and Shannon's information index (I) were calculated as 0.85, 0.16 and 0.29, respectively. The results of the Unweighted Pair Group Method with Arithmetic mean UPGMA dendrogram and Principal Coordinates Analysis PCoA analysis indicated a spatial representation of the relative genetic distances among 28 saffron samples and the 17 close relative species were categorized under two distinct groups. Saffron genotypes showed very limited genetic variation and according to the iPBS-retrotransposon data, its close relatives were C. cartwrightianus and C. pallasii subsp. pallasii.

This study sought to measure genetic diversity and phylogenetic structure among 196 individuals of saffron from 20 geographically separate accessions from Iran, Spain and Turkey using retrotransposon derived iPBS markers. Twenty-eight primers amplified a total of 179 polymorphic alleles with an average of 6.4 bands per primer. The average of parameters shannon's information index, genetic distance and gene diversity was 0.483, 0.286 and 0.841 respectively. Polymorphic information index ranged from 0.407 to 0.953 with an average of 0.824. Primers 2298, 2229 and 2393 with 0.953, 0.943 and 0.943 PIC respectively, identified as the most informative primers in this study. The results of phylogenetic trees showed that twenty saffron accessions were placed into four major clusters that matched with their geographical locations completely. These results are supported by principal coordinate analysis. Overall, we can confirm that iPBS markers as low cost and high efficient molecular markers are a powerful DNA fingerprinting for assessing genetic diversity and phylogenetic analysis among saffron accessions originating from different geographical regions.

Determination of association between molecular markers and agronomic traits provides an excellent tool for marker-assisted selection. In this study, multivariate stepwise regression analysis was used to estimate associations between SSR markers and some agronomic traits in saffron ecotypes. Two-year average values for the measured traits were used for association analyses. The results of stepwise regression analysis revealed significant associations between the traits and some of the studied loci. More than one informative marker was detected for most of the traits. Totally 25 informative SSR markers were identified in two years. Markers SCA382, SCA15 and SCD219 were associated with most traits under both years. These markers are considered to be relatively more reliable. Among the SSR primers, special attention should be drawn to primers SCA382, SCA15, and SCD219, which had the highest associated fragments with most traits in two years and could be considered for use as candidate markers in markerassisted selection.