Cytogenetic analysis of F₁, F₂ and BC₁ plants from intergeneric sexual hybridization between <i>Sinapis alba</i> and <i>Brassica oleracea</i> by genomic <i>in situ</i> hybridization

Abstract

Abstract By intergeneric sexual hybridization between Sinapis alba and Brassica oleracea , F 1 , F 2 and BC 1 progeny plants were produced. S. alba plants (genome SS, 2n = 24) were pollinated with B. oleracea (genome CC, 2n = 18), and the fertile F 1 plants were pollinated with B. oleracea to obtain BC 1 plants. GISH analysis showed that 10 out of 12 F 1 plants had 12 S. alba chromosomes (one full S chromosome set) and nine B. oleracea chromosomes (one C chromosome sets), representing the expected hybrids. However, two F 1 plants had 12 S chromosomes and 18 C chromosomes (two C chromosome sets), indicating unexpected hybrids. A maximum of three trivalents between C and S chromosomes were identified at metaphase I of semi‐fertile F 1 pollen mother cells (PMCs), which indicates homology and chromosome pairing between these two genomes. The C genome had obviously been doubled in two F 2 plants from selfed semi‐fertile F 1 plants. BC 1 plants consisted of 18 C chromosomes and different numbers of one, five and six additional S chromosomes, respectively. Monosomic alien addition lines developed in the present study can be used for B. oleracea breeding and Sinapis alba gene mapping.