ROLE OF THE CHROMOSOME 4B IN SUPPRESSING FROST-RESISTANCE IN WINTER-WHEAT (TRITICUM-AESTIVUM L.)

Frost resistance of different monosomic lines were investigated under controlled environment conditions. In the case of Cheyenne, Mironovska ya 808 and Rannyaya 12 a reduction in the degree of frost resistance w as observed when chromosomes 5A, 3B, 3A, 5B or 7A were missing. In two of the monosomic series there was also a drop in the level of frost r esistance in monosomic lines 5D and 7B. The frost resistance of monoso mic line 4B, on the other hand, was significantly better than that of the disome in two of the three cultivars. In previous experiments usin g substitution lines, the presence of a 4B chromosome originating from a variety with better frost resistance also led to an increase in fro st resistance. The results suggest that a gene suppressor for frost re sistance may be located on chromosome 4B.