A Database for Triticeae and Avena
II.43. Linkage data for rb and mt3.
G. W. R. Walker, Department of Genetics, University of Alberta, Edmonton, Alberta, Canada.
The following data are from studies in 1963-64. The genes gp2 and li are on chromosome 2 and Tsuchiya (BGN 3:99) has suggested they may be quite close together. Ribbon grass (rb) has been shown to be independent of lg, e, v, pr, and tr; mt3 is independent of l8, e, v, pr, and tr; (ibid) these two genes have not to the author's knowledge, been assigned to chromosomes.
This could be caused by low viability of mt3 mt3 rb rb plants in the mt3 - rb crosses, but this explanation does not hold for the mt3 - gp2 cross.
The data suggest that rb may be on chromosome 2, close to gp2 but this should be checked further because of non-linkages with v and tr. The unusual behavior of mt3 might be explained by its presence on chromosome 2 at an excessive distance from gp2, since such situations can give recombination values greater than 50%. If it is on chromosome 2 it must be on the long arm since Tsuchiya's telotrisomic data exclude it from the short arm (Tsuchiya and Singh, BGN 3:75). The value for li-gp2 from total data (15.1+ 4.1) tends to confirm Tsuchiya's suspicion that previous values (22.7, 25.3; Robertson, 1971) are too high.
References:
Robertson, D. W. 1965. Crop Science 5:33.
Robertson, D. W. 1971. Barley Genetics II:221.