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

Abstract

Chromosome pairing in the diploid species Avena strigosa (genome AsAs), A. eriantha (genome CpCp) and the hybrid between them was broadly similar to a previous report. The derived autoallotetraploid (A. strigosa×A. eriantha)2 showed greater variation of chromosome pairing than expected, particularly with regard to the frequency of rod bivalents and univalents. The hybrid (A. strigosa×A. eriantha)2×A. maroccana (genomes AACC) would be expected to form 14 bivalents if the AsAs and CpCp genomes of A. strigosa and A. eriantha were completely homologous, respectively, to the AA and CC genomes of A. maroccana. Chromosome pairing in the hybrid was poor, however, indicating that it is unlikely that A. eriantha or A. strigosa participated in the formation of the tetraploid A. maroccana.

Reduction in chiasma frequency and pollen fertility due to multiple chromosomal associations and univalents inSaxifraga diversifoliafrom alpine regions of northwest Himalayas (India)

“…The occurrence of univalent chromosomes in diploid plants has been attributed to the hybrid constitution of the genome (Stebbins and Pun 1953;Singhal 1982;Leggett 1998;Kumar et al 2012). However, in the present case, the fact that the univalent chromosomes in both varieties of S. diversifolia are not associated with any multiple association seems to be the result of asynapsis/desynapsis, as has been suggested by Singhal (1982), Maity and Datta (2009b) and Datta et al (2010).…”

“…Thus there is a negative effect of the occurrence of univalents on the pairing of chromosomes during meiosis and consequently on pollen fertility. Deleterious effects of univalents on meiotic course and pollen fertility have also been documented by several workers (Singhal 1982;Fiona et al 1988;Leggett 1998;Datta 2009a, 2009b;Datta et al 2010;Goyal and Khan 2010). On the other hand, Dnyansagar and Sudhakaran (1970) in Vinca rosea, Merker (1971) in Triticale, Gatt et al (2000) in some hybrids of Dahlia, and Palma-Silva et al (2004) in Vriesea and Aechmea showed that frequency of univalents is not correlated directly with reduced pollen viability.…”

Genomic relationships among sixteen species of Avena based on (ACT)6 trinucleotide repeat FISH

“…This result supports our result. However, Leggett (1998) indicated that A. eriantha was unlikely to have participated in the formation of A. magna. Liu et al (2017) inferred that A. nuda was related to A. murphyi.…”

On evolutionary pathways of Avena species

“…The A genome of the diploid progenitor could have obviously been the donor of A and D genomes in hexaploid species (Linares et al 1996). The latest data witness that the D genome is supposedly an unknown variant of the As-A'' genome, similarly to the B genome, but differing from the latter (Leggett 1996(Leggett , 1998.…”