CHROMOSOMES ASSOCIATED WITH WAXLESSNESS, AWNEDNESS AND TIME OF MATURITY OF COMMON WHEAT

Abstract

Selection 5075aB-2B-21, a waxless, bearded winter wheat, was subjected to monosomic analysis, using the Chinese Spring monosomic series. A number of structural differences between the chromosomes of the parents were observed including 2 translocations and an inversion, and at times one of the satellited chromosomes of Se 1. 5075 was observed to be dicentric. The single dominant gene for waxlessness was located on chromosome 2A. In addition to the recessive alleles of, or deficiencies for, the awn inhibitors Hd and B 2 being on chromosomes 4B and 6B, respectively, modifying genes affecting awnedness were located on chromosomes 3D and 7D. Both of these minor genes appear to modify the B 2 locus; however, the former results in an increase in awnedness whereas the latter results in a decrease in awnedness. The 3 members of homoeologus group No. 5 affect time of maturity, as do chromosomes 1A and 7D. Chromosome 5D bears a gene for lateness as compared with the allele present in Chinese Spring, whereas chromosome 5B possesses a gene for earliness. Chromosome 5A either possesses a gene for lateness or a gene for earliness that is imcompletely effective in the hemizygous condition. Chromosomes 1A and 7D bear genes for lateness. As shown by monosomic analysis and conventional F2 analysis, each of these traits is inherited independently of the other 2.