THE EFFECT OF THE PH1 GENE IN DIPLOID RYE, SECALE-CEREALE L

Experimental results demonstrated clearly that the dominant Ph1 allele of chromosome 5B of wheat affects teh homologous pairing of rye chromosomes. A rye-wheat monotelosomic 5BL addition line was produced and used for meiotic studies. Compared with 14-chromosome control plants, the 5BL addition to rye causes an increase in univalents and rod bivalent formation, i.e., a significant reduction of chiasma frequency (11.21 chiasmata per pollen mother cell). The 5BL telosome itself does not associate with any of the rye chromosomes. Thus, the double dosage of 5BL, present in hexaploid or octoploid triticale, could be one of the main causes of pairing failure of the rye genome.