Meiotic pairing in wheat–rye addition and substitution lines

Abstract

Chromosome pairing was examined in wheat–rye addition and substitution lines using the C-banding technique. It was found that both rye and wheat chromosomes affect each other's homologous pairing. The strongest diminution of wheat pairing (measured as bound arms per cell) was produced by chromosome 5R of rye (7.5 and 7.2% in 'Chinese Spring' – 'Imperial' and 'Holdfast' – 'King II' addition lines, respectively). The weakest diminution of wheat pairing was produced by chromosome 3R in the 'Chinese Spring' – 'Imperial' addition line (1.1%). The diminution of rye chromosome pairing produced by wheat chromosomes ranges from 6.9 to 48.4% ('Chinese Spring' – 'Imperial' and 'Holdfast' – 'King II' addition lines, respectively). When put into a wheat background, the rye chromosomes suffer a worse fate than the wheat chromosomes. For example, chromosome 6R reduces the wheat complement pairing in the 'Holdfast' – 'King II' addition line by 3.8% but its own pairing is reduced by 41.4%. The decrease in pairing of both wheat and rye homologous chromosomes in addition and substitution lines is a complex process in which factors such as genes controlling meiotic pairing, constitutive heterochromatin, and cryptic wheat–rye interactions can play important roles.

The effect of Secale cereale L. heterochromatin on wheat chromosome pairing

“…Our results do not discriminate between the effects of individual rye chromosome. There is some evidence in this respect in earlier publications (Orellana et al, 1984;Gupta & Fedak, 1986). We confirm the observation of a general negative effect of rye telomeric heterochromatin on wheat pairing.…”

“…Moreover, it has been suggested that reduction of telomeric heterochromatin stabilizes rye chromosome behaviour at first metaphase in Triticale (Thomas & Kaltsikes, 1976;Merker, 1976;Schlegel, 1982). Orellana et al (1984), examined chromosome association in wheat-rye addition and substitution lines using C-banding. They found that both rye and wheat chromosomes affect each other's homologous pairing and discussed the role of constitutive heterochromatin in the failure of chromosome association at first meiotic metaphase.…”

Meiotic expression of modified chromosome constitution and structure in × Triticosecale Wittmack

“…In hexaploid triticale (Thomas and Kaltsikes, 1974;Lelley, 1975b;Schiegel, 1978a;Jung and Lelley, 1985a, b;Jung et aL, 1985;Galindo and Jouve, 1989) and in wheat-rye addition lines (Schlegel, 1978b;Orellana et a!., 1984), rye Fominaya and Orellana (1988) demonstrated a phenomenon of interference between wheat and rye chromosomes as a cause of the decrease of rye-rye and wheat-wheat homologous pairing observed at metaphase I in triticale with respect to their corresponding rye and wheat parents.…”

P-stress Tolerance in Some Rye-introgressed Bread Wheats and Association of the Trait with Specific Rye Chromosome(s)

“…In the F 1 s of these crosses, occasionally 2 univalents/laggards (Fig. 1B) were also observed which could be due to the precocious terminalization of 6R chiasmata (Orellana et al 1984). However, in the hybrid of RL 107-2, 4 univalents and laggards were observed (Fig.…”