CHROMOSOME RELATIONSHIPS BETWEEN AVENA SATIVA (6X) AND AVENA PILOSA (2X)

Abstract

A. sativa (6x) was successfully crossed with A. pilosa (2x) the derived amphiploid was produced by treating the F1 hybrid with colchicine. Chromosome pairing in the F1 hybrid indicated that the pilosa genome was partially homologous with one of the sativa genomes. The lower chromosome pairing in the pilosa-sativa F1 than in the sativa-hirtula F1 showed that the genome of pilosa is differentiated further from its corresponding genome than that of hirtula. from the A genome of sativa. In both amphiploids and in the inter-amphiploid hybrid, there was a strong preferential pairing o{ homologous chromosomes. The pilosa and hirtula chromosomes did not associate freely in the inter-amphiploid hybrid. The results are discussed in relation to differential affinity and also to the possibility of a genetic system controlling the diploid-like cytological behavior in A. sativa. Another interpretation was based on the possibility that the genome of pilosa is related to a genome other than the A of sativa.