Previous issues of MNL have reported an association between the browning of silks at the tips (5-10 minutes after they are cut) and red cob color (MNL 59:40) and P locus control of silk browning (MNL 60:55). The results of tests we have conducted suggest a very close linkage relationship between factors for cob color and silk browning (<2% crossovers).
We crossed a red-cob silk browning line (T204) with a white-cob green-silked line (NC34) and observed segregation in the F2 and first backcrosses. The backcross to T204 was all red-cobbed with browning silks, but the F2 and backcross to NC34 segregated about 3:1 and 1:1, respectively, for both red cobs and silk browning. The white-cob silk browning, and red-cob green silk classifications represented about 1.7% of the progeny in each of the F2 and BC2. Each generation was represented by at least 350 plants when summed over two years and no classification within generations contained fewer than two individuals.
These data clearly suggest two separate, but closely linked, dominant factors in control of red cob color and silk browning.
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