Chromosome Associations in Triploid, Tetraploid, and Pentaploid Hybrids of Avena magna (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.

Chromosome and genomic relationships between the diploid species Avena strigosa, A. eriantha and the tetraploid A. maroccana

“…The general lack of homology between the AsAs and CpCp genomes in the diploid hybrids reported here and by Nishiyama & Yabuno (1975), together with the chromosome pairing data of the triploid hybrids involving AA and CC genome diploid species and A. maroccana (Sadanaga et al, 1968;Kummer & Miksh, 1977) and the synthetic allotetraploid Av5616, indicate that it is probable that the multivalent formation recorded in the Av5616 hybrids results from translocations between AA and CC genome chromosomes.…”

“…Multivalents were recorded in 77 per cent of PMCs, a frequency over twice as high as the combined multivalent frequency reported in the triploid hybrids A. strigosa A. maroccana (Sadanaga et al, 1968) and A. eriantha A. maroccana (Kummer & Miksh, 1977). Interpreting these differences is difficult because the genotypes used to produce the triploid hybrids differed from those used in this study, which could, in part, account for the discrepancies.…”

Notes on species delimination, species relationships and polyploidy in Avena L.

“…strigosa or A . longiglumis can be produced, and they have been studied by several workers SADANAGA et al ., 1968 ;RAJHATHY and SADASIVAIAH, 1969 ;LADIZINSKY, 1969 ;LADIZINSKY, unpubi . ) .…”

The introgression of characters of the wild oat Avena magna (2n=4x=28) into the cultivated oat A. sativa (2n=6x=42)

“…The chromosomes of the tetraploid wild oat Avena magna, which is morphologically similar to the hexaploid species A. sterilis, have been shown to have a closer homology with their corresponding chromosomes in the hexaploid species of Avena than the A. barbata group of tetraploids (SADANAGA et al, 1968;RAJHATHY & SADASIVAIAH, 1969;LADIZINSKY, 1969 (1971) proposed that A. magna was part of a complex that included the tetraploid progenitor of hexaploid species. Although the extent of chromosome pairing observed in the hybrids indicate that the two A. magna genomes are related to two of the A. sativa genomes, the hybrid did not form 14 bivalents and 7 univalents as expected if the genomes were completely homologous.…”