Hybridization between Picea rubens and Picea mariana: differences observed between montane and coastal island populations

Foliage was collected from natural stands of montane and island red spruce (Picearubens Sarg.) and black spruce (Piceamariana (Mill.) BSP) to examine within- and among-population genetic variation. Samples were scored for frequencies of nuclear ribosomal DNA (rDNA) alleles, and mitochondrial and chloroplast haplotypes. Samples were classified as red spruce, black spruce, or hybrid using two molecular methods: a three-character discriminant function based on molecular markers or a three-character molecular index. These results were found to be highly congruent with classification based upon a discriminant function using morphological traits. Among montane populations, hybridization and introgression between red and black spruce did not appear to be a major factor in the observed patterns of variation on elevational transects on Mount Washington and Mount Lafayette, N.H. However, extensive hybridization and introgression were detected among populations on Isle au Haut, Maine. The Mount Lafayette population displayed low variation in rDNA alleles compared with populations on Mount Washington and a range-wide provenance test in Stewartstown, N.H

Parental origins of the cultivated tetraploid sour cherry (Prunus cerasus L.)

Sour cherry (Prunus cerasus L.) is an agriculturally valuable tree that produces fruits used in a range of culinary dishes, beverages, and other products. The progenitor species and number of origins of sour cherry remain unresolved. Here, we performed phylogenetic analyses of plastid genomes and nuclear genes from nine wild species and three historically important sour cherry cultivars. Our analyses identified Prunus fruticosa and Prunus avium as the closest extant relatives of the progenitor species of tetraploid sour cherry. Furthermore, our analyses revealed P. fruticosa as the likely maternal contributor. These findings and transcriptomic datasets should serve as valuable new resources to guide future breeding efforts in sour cherry