Fertility of 17 Colchicine‐induced Perennial Triticeae Amphiploids Through Four Generations1

Abstract

Seed set and pollen stainability were determined for 17 perennial colchicine‐induced amphiploids (2n=42 or 56) derived from sterile triploid and tetraploid F1 hybrids of Agropyron, Elymus, Hordeum, and Sitanion species. Chromosome doubling restored fertility; however, the level of fertility in the originally doubled hybrids (C0 generation) declined in advanced generations. Fertility stabilized in most hexaploids after the C1 generation, whereas fertility of most octoploids continued to decline. Seed set (seeds/spike) of nine hexaploid amphiploids averaged 17.5, 18.9, and 17.4 in the C1, C2, and C3 generations, respectively. Eight octoploid amphiploids averaged 8.1, 9.1, and 4.2 seeds/spike, respectively, over the same three generations. Synthesis of fertile Triticeae grass species appears to be feasible at the hexaploid level but not at the octoploid level.