Linkage data on several unlinked characters were gothered and analyzed by graduate students.
1. The silky which appeared in the F2 of a cross between two inbred lines segregated in an F2 to give a ratio of 15 normal : 1 si and approximately 3:1 in a backcross.
Red collar (base of tassel glumes) vs. green segregated 9:7 in F2 in one of these cultures. Based on small numbers, si was independent of red collar, sr and ms (this ms was supposed to be as but did not show linkage with sr, also the ears were normal). Red collar was also independent of this same ms and sr. This silky shows no linkage with ms1.
Backcross tests indicated no linkage between Pl and red collar, a result differing from that reported previously (News Letter 18:16‑17. 1944 ‑ Pl vs. red collar = 6.6 per cent recombination). This difference is explainable if red collar is due to complementary factors.
I. Z. Hasanain
2. Woodworth's vp gives no evidence of linkage with ms1. To determine the order of Y, pb, and ms; all very closely linked, Y + ms/y pb+ plants were crossed with y pb ms/+. One y + ms and one y pb ms were obtained, suggesting that this is the order of the three genes.
H. A. McLennan
F. H. White
3. One stock from X‑ray treatment has 10 chromosome pairs and about 20 per cent of pollen abortion. The sterility shows linkage with factors in chromosome 2: 43.5% with gl2, 34.6% with B, and 15.5% with v4.
Preliminary cytological examination reveals bridges with fragments, indicating an inversion is the probable cause of the sterility, and that the centromere is outside the inversion. The ears show normal fertility.
W. A. Russell
4. A survey of the knob numbers (and where possible the positions) in 20 inbred lines used in the breeding program here is being made to determine possible relationships with plant characters and with combining ability. The knob number varies from two to at least eight.
M. V. Vachhani