Invasive Species Compendium

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Abstract

Cytogenetic studies on Brassica campestris primary trisomics.

Abstract

Meiosis, trisomic transmission, and inheritance of erucic acid content were studied in a nucleolar trisomic (2891) and a non-nucleolar trisomic (2881) of B. campestris. The two trisomics originated from a B. campestris-B. alboglabra monosomic addition line whose alien chromosome carried the gene for erucic acid content. Meiotic analyses revealed that the trivalent frequencies in the PMCs at diakinesis/metaphase I were 33.3% and 20% in 2891 and 2881, respectively. The transmission rates of the extra chromosome through the ovule in 2891 and 2881 were about 30.6 and 32.4%, respectively. The inheritance of erucic acid content was investigated in the two crosses, 2891 × B. campestris landrace Wu Chang Bei You Cai and 2881 × B. campestris landrace Xi Shui You Cai Bei. The segregation of erucic acid content in the F2 progenies of the selfed trisomic F1 plants from the two crosses showed a disomic inheritance pattern, thus indicating that the trisomy in 2891 and 2881 did not involve the chromosome carrying the erucic acid gene. The genetic divergence of homoeologous chromosomes between B. campestris and B. alboglabra is discussed.