Polyploid structure in the Setaria sphacelata complex

Abstract

Meiotic behaviour and fertility were studied in hybrids between tetraploid, hexaploid, octaploid, and decaploid strains in the Setaria sphacelata complex, the strains studied including S. sphacelata sensu stricto, S. sphacelata var. stolonifera S. anceps, and S. trinervia. Metaphase and telophase data in 5x (4x × 6x), 7x (6x × 8x), 9x (8x × 10x), 6x (4x × 8x), and 8x (6x × 10x) plants allowed the interpretation of genome homologies as tetraploid AB, hexaploid AB(A'/B1), octaploid AB(A′/B′)(A′/B′), and decaploid AB((A′/B′)(A′/B′)(A′/B′). It is argued that the complex is an autopolyploid series, but further work is necessary before the relationships between the A and B genomes can be determined.