Interspecific hybridization between Brassica carinata and Brassica rapa

The crossability between Brassica carinata (BBCC, 2n = 34) and Brassica rapa (AA, 2n = 20), and the cytomorphology of their F-1 hybrids were studied. Hybrids between these two species were only obtained when B. carinata was used as the Female parent. The hybrid plants exhibited intermediate leaf and flower morphology, and were found to be free from white rust and Alternaria blight diseases. One of the four F-1 plants was completely male sterile, while the remaining plants had 4.8, 8.6, and 10.9% stainable pollen, respectively. No seed was produced on hybrid plants under self pollination or in backcrosses; but seed was obtained from open pollination. The occurrence of the maximum of 11 bivalents as well as up to 44.8% of cells with multivalent associations in the form of trivalents (0-2) and a quadrivalent (0-1) in the trigenomic triploid hybrid (ABC, 2n = 27) revealed intergenomic homoeology among the A, B and C genomes. Meiotic analysis of F-1 hybrids indicated that traits of economic importance, such as disease resistance, could be transferred from B. carinata to B. rapa through interspecific crosses.