Meiotic Irreglarities in Avena sativa L./A. sterilis L. Hybrids and Breeding Implications1
- M. S. McMullen,
- R. L. Phillips and
- D. D. Stuthman2
The cytogenetic relationships of nine Avena sativa L. (2n = 6x = 42) and seven A. sterilis L. (2n = 6x = 42) genotypes were evaluated by studying microsporogenesis, seed set, and pollen fertility of the lines and their hybrids. A higher frequency of meiotic irregularities was observed in all A. sativa/A. sterilis hybrids relative to the self-pollinated parental lines or the A. sativa/A. sativa and A. sterilis/ A. sterilis hybrids. Chromosomes of most of the A. sterilis lines clearly differed in their degree of homology with those of A. sativa. Predictions of the chromosome constitutions of individual A. sterilis lines were made based on crosses with A. sativa cultivars, and tested with data from crosses among each other. Univalents and multivalents frequently were observed in meiotic cells of A. sativa/A. sterilis hybrids. The frequency of univalents increased from diakinesis to metaphase I suggesting desynapsis. The univalents ultimately formed micronuclei in the microspore quartets; micronuclei frequency determinations may provide a useful measure of genetically controlled meiotic irregularity in hexaploid oat hybrids. This information may be useful in selecting the most promising parents for gene transfer. Avena sterilis C.I. 8340 appeared to be the most homologous to A. sativa and thus selection among its interspecific progeny will probably more easily separate desirable from undesirable A. sterilis traits.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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