Jm. Mcgrath et al., Genetic diversity in selected, historical US sugarbeet germplasm and Beta vulgaris ssp maritima, THEOR A GEN, 98(6-7), 1999, pp. 968-976
Diversity among sugar beet accessions released over the first 50 years of p
ublic breeding in the United States was examined to ascertain a baseline of
genetic diversity and to gauge the effect of breeding on the loss or gain
of diversity over this time period. Accessions were chosen as released germ
plasm from the major breeding stations contributing to the US germplasm poo
l and their presumed ancestors from Europe, including representatives for t
he wild forms Beta vulgaris ssp. maritima. Sixty nine polymorphic RAPD frag
ments were used for gene frequency analysis, and heterozygosity was determi
ned within and among groups of accessions related either by breeding statio
n or simply inherited agronomic characters for monogerm seed and restoratio
n of fertility in a cytoplasmic male-sterile background. In general, hetero
zygosity within releases declined with time, but total genetic diversity in
the US germplasm pool remained constant. Breeding for the agronomic charac
ters had a marked influence in reducing diversity.