Basic information for the use of primary trisomics in genetic and breeding research

Summary An attempt is made to arrange the basic information needed for using primary trisomics in localizing single and complementary dominant and recessive genes, accounting for random complete chromatid and random chromosome association, for heterozygosity of the trisomics and for female and male transmission rates. The expected ratios are given separately for the di-, tri- and tetrasomic group in each population. Also the ratios in the total populations have been calculated for different rates of female and male transmission of the extra chromosome. Both the backcross procedure and that of selfing trisomic F₁ plants are considered. Finally the use of trisomics for studying quantitative characters is discussed in connection with the breeding and incompatibility system of the crops and in relation to the frequent morphological differences among trisomics as well as between trisomics and their disomic counterpart.