3. Chromosome 6 Linkage Studies.--A stock of ms pb has been established. The linkage of pb with Y is very close.
Classification for su2 has not been very satisfactory in material grown here at Minnesota. The data reported by me in the Coop Letter of March 23, 1937 (p. 15) indicated the order y-pl-su2, with about 8% recombination between su2 and Pl. It was noted there that the separation for Yy was poor. Since then Horovitz et al. (Anales Inst. Fitotecn. S. Catalina 3:37, 1941) reported a sux between Y and Pl. One backcross test with Pl using su2 as the female parent indicated 15% recombination, but all the recombinations were found in the non-sugary class. One test of su2 vs ms was set up as follows:
Red glume collar in the tassel florets appears to show linkage with Pl in certain cultures, not in others.
A silky character is closely associated with antherless in the stock obtained from the Corn Coop. This silky vs Y showed 16.5% of recombination.
Trisomic tests for location of new factors in chromosome 6 : bas (barren stalk in a sweet corn), a new silky from a single cross, and a new stock of tinged (tn) show normal disomic ratios. The midget dwarf (mi) shows closer fit to a trisomic ratio than to disomic, although classification was not too certain.
C. R. Burnham
The following have assisted in the work at various periods: Gertrud Stanton, C. H. Li, T. J. Liang, and H. R. Highkin.