Chromosome Associations in Triploid, Tetraploid, and Pentaploid Hybrids of <i>Avena magna</i> (2n=28)¹

Abstract

Diploid Avena strigosa Schreb. and A. wiestii Steud., tetraploid A. abyssinica Hochst., and hexaploid A. sativa L. and A. sterilis L. were cross‐compatible with A. magna Murphy and Tcrrell All hybrids except the pentaploids were sterile. Partial homology of the A genome of the diploid species with one genome of A, magna was indicated by the chromosome associations observed in the triploid hybrids A. magna ✕ A. wiestii and A. strigosa ✕ A. magna . In the tetraploid hybrid, A. abyssinica ✕ A. magna , chromosome associations suggest that the two species have one or both genomes partially common. In the pentaploid hybrids, the frequencies and kinds of chromosome associations observed suggest that A. magna may have two genomes partially in common with two genomes of the hexaploid species, a common genome and the remaining genomes partially common, or two genomes partially in common with the three genomes of the hexaploids.