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 b ackcrossed to its parental B. campestris (AA, 2n=20) to develop monoso mic addition lines that contain the different chromosomes of the other parent B. alboglabra (CC, 2n=18). Special emphasis was put on identif ying monosomic addition lines with B. alboglabra chromosome(s) carryin g genes for black seed colour. Four different types of monosomic addit ion plants were obtained. One of them harboured a B. alboglabra chromo some with gene(s) for black seed colour while another type of monosomi c addition plant had the B. alboglabra chromosome with the gene for wh ite flower colour. The remaining two carried hitherto unmarked C-genom e chromosomes and were distinguished from each other by the morphology of the alien chromosome at diakinesis of meiosis. Meiotic studies rev ealed that the monosomic addition plants for the white flower colour o r black seed colour had a higher trivalent frequency in the pollen mot her cells when compared with the two unmarked monosomic addition plant s. Two different types of double-monosomic addition plants were also o btained. Such double-monosomic addition plants will be useful to revea l intragenomic homoeology of the B. alboglabra chromosomes.