Genetic diversity among European cultivated spelt revealed by microsatellites

Spelt and common wheat constitute two of the six groups of the hexaploid wh eats with an AA-BBDD genome. Spelt culture has been progressively replaced by that of common wheat which out-yields spelt under high-input conditions. In the last decades, spelt breeders intended to introduce the yield-potent ial and bread-making qualities of common wheat into spelt, by frequent cros sings between accessions of these two different groups. The present study a ims at determining the genetic basis of modern spelt cultivars in terms of intra-group variability and inter-group (spelt vs common wheat) distances, by using microsatellite markers developed for common wheat. The allelic com position of 30 spelt and nine common wheat accessions was determined at 17 microsatellite loci. The coefficient of co-ancestry (f) and the genetic dis tances (1 - proportion of shared alleles) based upon allelic composition we re calculated for all pairs of accessions. Two dendrograms were constructed using the UPGMA method. Amplification products were found for all loci on most accessions. A total of 113 alleles was identified, of which 60.2% were specific to spelt or common wheat. The correlation between (1 - f) and the genetic distance was high (0.701***). The mean pairwise genetic distance w as 0.656 +/- 0.181 over the 39 accessions, 0.706 +/- 0.14 among common whea t and 0.573 +/- 0.172 among spelt. The mean genetic distance between spelt and wheat was 0.782 +/- 0.113. The two dendrograms were in accordance with each other and clearly separated the spelt from the common wheat accessions . It is concluded that microsatellites developed for common wheat and dista nces based on the proportion of shared alleles are powerful tools for recon structing phylogenies in spelt, and that the genetic basis of modern spelt cultivars is narrow despite frequent crosses made with bread wheat.