Green Revolution Dwarfing Alleles Are Rare in Spring Bread Wheat Germplasm Grown in Russia

The Green Revolution dwarfing alleles Rht-B1b and Rht-D1b shorten the stem and reduce lodging, and under intensive management often raise yield, although this advantage may disappear in dry or low-input environments. Their frequency in spring bread wheat grown in Russia has not been established. We genotyped 370 accessions. None carried Rht-B1e or Rht-B1p, only eight carried Rht-B1b (2.2%) and one, Zolushka, carried Rht-D1b (0.3%); two were heterogeneous at Rht-B1. These figures describe this collection, not a probability sample of Russian spring bread wheat. Pedigrees trace the eight Rht-B1b carriers to five sources: three inherited the allele from a winter bread wheat parent, two from CIMMYT semi-dwarf material, and three belong to a single introduced lineage; none derives it from Russian spring wheat breeding. In 43 accessions grown in Moscow over three seasons, the three Rht-B1b carriers were 15.4% shorter than the 39 wild-type accessions (60.7 versus 71.8 cm, p = 0.021), whereas spike traits and grain yield in Moscow and Omsk did not differ significantly; with three carriers these comparisons are exploratory and small effects cannot be excluded. Because one field-evaluated carrier was as tall as the wild type, marker-based identification is needed wherever these alleles are deployed.