MEIOTIC ASSOCIATIONS IN BARLEY LINES WITH EIGHT PAIRS OF CHROMOSOMES AND THEIR HAPLOIDS

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Abstract
Meiosis was studied in pollen mother cells and embryo sac mother cells of 7 lines of 8-paired barley (Hordeum vulgare L.) in diploids (2n = 16) and haploids (2n = 8). Translocation 5-7a, whose breakpoints were distal on chromosome 5 and in the satellite of chromosome 7, was found in all lines. The extra fragment chromosome (8) was a normal or translocation form of chromosome 5 deficient for terminal regions. In diploids the extra chromosome behaved regularly at meiosis except for occasional univalent-formation. It could form a symmetric ring bivalent but never formed chiasmata with other chromosomes. In haploids it formed a low frequency of chiasmata with chromosome 5 but this frequency was reduced when the terminal region of chromosome 5 paired homologously with the satellite region of 7. Based on the hypothesis used to explain chromosome pairing behavior, it should be possible to derive and identify additional 8 paired lines that would be useful for breeding.