II. 6. Absence of crossing-over of ert-c in crosses involving T2-3a and additional information on the linkage of uz and msg5.
H. E. Bockelman and R. F. Eslick, Depts. of Plant Pathology and Plant and Soil Science, Montana State University, Bozeman, MT 59715, USA.
Translocation stock, T2-3a (Gull), carries ert-c. We have studied this translocation in crosses with Atlas 46 (C.I. 7323), La Mesita (C.I. 7565), Osiris (C.I. 1622), Modoc (C.I. 7566), and Turk (C.I. 14400). A total of 1334 F2 plants were classified for ert-c and semi-fertility. See Table 1.
Table 1. F2 data from crosses with T2-3a.
Only one plant was identified as a cross-over phenotype. A previous report has placed the T32a breakpoint near the centromere (Perrson, 1969a). Data from Persson (1969b) and Eslick and McProud (1974) place ert-c near the centromere of chromosome 3. Our data suggests two possibilities. One, ert-c and T32a are tightly linked. Two, crossing-over between ert-c and T32a due to ert-c being located in the interstitial region between the centromere and T32a. This would place the T32a breakpoint in the same arm as ert-c.
We have further information on the linkage of uz and msg5. A total of 4503 F2 plants from crosses between uz uz msg5 msg5 and Atlas 46, Trebi (C.I. 936), La Mesita, Modoc, Osiris, and Turk, were classified. The results are shown in Table 2. The combined data give a linkage value of 7.6 + .4. In a previous report (Eslick and McProud, 1974) the linkage value was estimated at 13.1 + 2.3 using smaller population sizes.
Table 2. F2 data on the linkage of uz and msg5.
References:
Eslick, R. F. and W. L. McProud. 1974. Positioning of genetic male sterile 5 (msg5) on chromosome 3. BGN 4:16-23.
Persson, G. 1969a. An attempt to find suitable genetic markers for dense ear loci in barley. I. Hereditas 62:25-96.
Persson, G. 1969b. An attempt to find suitable genetic markers for dense ear loci in barley. II. Hereditas 63:1-28.
