ADDITION OF BRASSICA-ALBOGLABRA BAILEY CHROMOSOMES TO BRASSICA-CAMPESTRIS L WITH SPECIAL EMPHASIS ON SEED COLOR

A resynthesized Brassica napus line (AACC, 2n = 38) was successively backcrossed to its parental B. campestris (AA, 2n=20) to develop monosomic addition lines that contain the different chromosomes of the other parent B. alboglabra (CC, 2n=18). Special emphasis was put on identifying monosomic addition lines with B. alboglabra chromosome(s) carrying genes for black seed colour. Four different types of monosomic addition plants were obtained. One of them harboured a B. alboglabra chromosome with gene(s) for black seed colour while another type of monosomic addition plant had the B. alboglabra chromosome with the gene for white flower colour. The remaining two carried hitherto unmarked C-genome chromosomes and were distinguished from each other by the morphology of the alien chromosome at diakinesis of meiosis. Meiotic studies revealed that the monosomic addition plants for the white flower colour or black seed colour had a higher trivalent frequency in the pollen mother cells when compared with the two unmarked monosomic addition plants. Two different types of double-monosomic addition plants were also obtained. Such double-monosomic addition plants will be useful to reveal intragenomic homoeology of the B. alboglabra chromosomes.