Crossability of Brassica carinata and B. tournefortii, and cytomorphology of their F1 hybrid

Abstract

Reciprocal crosses between Brassica carinata (BBCC, 2n=34) and B. tournefortii (TT, 2n=20) were attempted in order to determine crossability between the species, carry out chromosomal associations among the B, C and T genomes, and to study morphology of the interspecific hybrids. A hybrid between these 2 species was obtained only when B. carinata was used as a female parent. Morphologically, the hybrid was intermediate between the progenitor species but its leaves resembled B. carinata. The F, plant was tall but grew very slowly. The hybrid was almost male sterile, showing only 2.3% pollen stainability. Meiotic studies of trigenomic triploid hybrid (BCT, 2n=27) showed various chromosome configurations including quadrivalents (0-1), trivalents (0-2), bivalents (2-9) and univalents (5-23). Only 5 univalents were recorded to have occurred; otherwise trivalents and bivalents were observed in pollen mother cells of the BCT hybrid. A few chromosomal association could be expected through allosyndesis which suggests the possibility of transferring genes across the species through interspecific hybridization. © 2012 The Japan Mendel Society.