Spontaneous somatic transfer of a segment from a wheat addition chromosome into the rye genome

Abstract

Wheat chromosome 3B when added to the rye genome causes resistance to powdery mildew of rye (Erysiphe graminis DC. f.sp. secalis Marchal) as the result of the action of the gene Rpm1. Wheat chromosome 3B also carries the gene Got-B3 for glutamate oxaloacetate transaminase. In two independent, vegetatively reproduced additions of 3B to rye, the extra wheat chromosome appeared to have been lost spontaneously, but both genes were still present. The rye chromosome into which the genes had been transferred could not be identified. Chromosome 3R appeared to be morphologically unchanged, no telomeric heterochromatin normally present in any rye chromosome had disappeared, and no wheat B-genome centromeric heterochromatin was observed. At meiosis the chiasma frequency was reduced, resulting in the frequent formation of one univalent pair, and occasionally two univalent pairs. No specific chromosome pair was preferentially involved. The wheat genes could not be transferred to the progeny by selfing nor by reciprocal back-crossing, but gametes without these genes were functional. The plants were semisterile.Key words: wheat chromosome addition, rye, somatic translocation, univalents, mildew resistance.

Cytogenetics in Plant Breeding

“…Melz and Thiele (1990) report the loss during vegetative reproduction of a wheat chromosome originally present as an addition to diploid rye, accompanied by the apparent transfer of some of the wheat genes to the rye genome. Melz and Thiele (1990) report the loss during vegetative reproduction of a wheat chromosome originally present as an addition to diploid rye, accompanied by the apparent transfer of some of the wheat genes to the rye genome.…”

Rye–wheat hybrids: the production of wheat chromosome additions to rye

“…Their result indicates that certain chromosome arms in rye are not essential for the survival of the plant. Therefore, it might be possible to generate either centric break fusions of rye-wheat chromosomes or introgressions of wheat chromatin into rye as demonstrated by Schlegel and Kynast (1988) and Melz and Thiele (1990). Such genetic stocks may allow the study of the influence of ,the rye background on wheat gene expression.…”

“…Schlegel and Kynast (1988) transferred wheat chromatin to rye using an irradiation technique originally suggested by Sears (1956). Melz and Thiele (1990) reported a spontaneous somatic transfer of a segment from a wheat addition chromosome into the rye genome.…”