I now have enough data on the yellow-albescent situation to indicate quite clearly that my hypothesis last spring was correct. I have two factors for yellow endosperm - "Yx" linked with al (p = .01 - .02) and Y1 linked with Pl (p = .25 - .30). I have found no evidence of linkage between these two Y's or between Yx and Pl or py. Selfed plants of the constitution Y1 y1 Yx yx give F2 distributions of nine yellow to seven "not yellow" ranging from "lemon" to "white". I selfed some plants from the yellow seeds in such an F2 and found three groups as follows:
which came pretty close to the 1:4:4 expected. I grew a few seedlings from some of the three-to-one ears for linkage tests. (F2 was also segregating for Pl, al, and py). Some showed linkage with Pl, some with al. Only two were segregating for both Pl and al and the distributions for these were as follows:
.42 (or .58)
Of course, results like these don't rule Yx (or al) out of #6 if #6 is very long "genetically" but at least it is at considerable distance from the known factors of that group with which it has been tested. Maybe the trisomics will clear that up. Besides the 9:7, the dihybrid ratios 3:5 and 1:3 have been obtained.