CHROMOSOME AND GENOMIC RELATIONSHIPS BETWEEN THE DIPLOID SPECIES AVENA-STRIGOSA, A-ERIANTHA AND THE TETRAPLOID A-MAROCCANA

Chromosome pairing in the diploid species Avena strigosa (genome AsAs) , A. eriantha (genome CpCp) and the hybrid between them was broadly si milar to a previous report. The derived autoallotetraploid (A. strigos a x A. eriantha)(2) showed greater variation of chromosome pairing tha n expected, particularly with regard to the frequency of rod bivalents and univalents. The hybrid (A. strigosa x A. eriantha)(2) x A. marocc ana (genomes AACC) would be expected to form 14 bivalents if the AsAs and CpCp genomes of A. strigosa and A. eriantha were completely homolo gous, respectively, to the AA and CC genomes of A. maroccana. Chromoso me pairing in the hybrid was poor, however, indicating that it is unli kely that A. eriantha or A. strigosa participated in the formation of the tetraploid A. maroccana.