The dominant white cap (Wc) endosperm factor is linked with brittle stalk (bk2) in chromosome 9, the backcross numbers being 135 Wc +, 67 Wc bk, 65 wc +, 143 wc bk, or 32.2 per cent recombination. With T 8-9a there was 30 per cent recombination (Wc - T 8-9a = 18:33:68:25). Since tests reported previously indicated no linkage with waxy (News Letter 18: 16. 1944) the order appears to be wx - bk2 - Wc; or wx - T 8-9a - Wc.
A brown midrib character which appeared in a sh wx gl10 culture seems to be genetically different from the other three brown midribs, and therefore is bm4.
Viviparous (vp5) is the same as Woodworth's vp as shown by intercrosses. Tests are in progress to determine the linkage group to which vp5 belongs. This will also locate one of the factors for yellow endosperm (unless vp5 itself causes the color effect).