Gene Transfer from Wild Tetraploid Avena Magna to the Cultivated Hexaploid A. Sativa. I. Bc₁ Progeny

Five ²Avena sativa (2n-42) genotypes, JHO-801, UPO-94, IGO-500,OS-6 and OS-7 were used as female parents and crossed with A. magna (2n = 28). The pentaploid self-sterile hybrids obtalaed were backcrossed to A. sativa. Out of 1509 florets pollinated with A. sativa pollen, only six seeds developed, four of which germinated giving rise to BC, plants. The morphology, cytology and fertility of these plants were studied. Some of the A. magna characters, viz., strong awns, grey and pubescent lemma and high tillering expressed themselves in these plants. The chromosome. number varied from 2n = 33 to 2n = 40 with high frequency of blvalents. Further backcrossing to A. sativa was successful in two BC₁ plants. Some selfed seeds were obtained from three plants. It is expected that subsequent backcross and selfed progenies will give rise to stable hexaploid lines with gene introgression from A. magna.