Abstract
Thirty-two progenies showed a mean of 4.3 ± 0.3% recombination between ms-1, a gene for male sterility and c-1, a seedling marker gene. The closeness of this linkage makes it useful for producing F1hybrid seed of Brassica vegetable crops. Differential viability, acting prior to seed germination and associated with the c-1 locus, resulted in either a deficiency or a surplus of ms-1 ms-1 plants depending on the linkage phase. The mean viability of plants with the C-1 phenotype was 1.26 ± 0.03 times that of c-1 c-1 plants. The genetic stocks studied bred true for a quadrivalent at meiosis I. This presumed duplication was traced through seven generations but was not responsible for the ms-1 c-1 linkage.