Effects of accessory chromosomes of rye in the gene environment of hexaploid wheat

The “Lindström strain” represents a union between the 42 chromosomes of bread wheat and a variable number of accessory chromosomes from rye. In order to check the effects of the accessories especially on fertility and vigour, measurements were taken in the Lindström strain and Transbaikal rye, the strain representing the donor of the accessories. These chromosomes reduce pollen fertility in the Lindström strain at least as efficaciously as in rye. There is also a pronounced negative effect on female fertility, but marked or absolute sterility is attained still more rapidly in varieties of rye. This difference is ascribed to a slight buffering effect of the 42 wheat chromosomes. In the Lindström strain, in contrast to rye, there was a significant positive correlation between acc. chromosomes and vegetative vigour. Probably due to a slight buffering effect of the wheat chromosomes, vegetative vigour is less negatively affected by accessories in the Lindström strain than in rye. Increase in straw weight may then result from an indirect effect of the sterility induced by the accessories. The nutrients not utilized for seed production may instead favour vegetative development. In spite of various weak indications of positive functions of accessory chromosomes in rye and some other organisms the present data demonstrate that their primary negative effects are predominant in the Lindström strain as well as in rye varieties.