Cytomorphology of <i>Brassica juncea </i>× <i>B. napus</i> Hybrids and Pattern of Variation in the F₂ Derivatives

Abstract

Summary Interspecific hybridization is an important tool to elucidate intergenomic relationships, transfer characters across species, create genetic variability, and to develop synthetic amphidiploids. It has been widely used for improving Brassica. The present study was conducted to find out the crossability between Brassica juncea (AABB, 2n=36) and B. napus (AACC, 2n=38), analyze chromosome association in the F 1 hybrids, and to estimate variability in F 2 progenies of the cross. The crossability between B. juncea and B. napus was higher when B. juncea was used as the female parent. The hybrids, in general, were vigorous and intermediate in morphological attributes. The meiotic studies of F 1 plants of cross B. juncea B. napus (AABC, 2n=37) exhibited 10 bivalents in the majority of the pollen mother cells (PMCs) analyzed. A maximum of 14 bivalents in AABC hybrids and the presence of multivalent associations were attributed to the auto-and allosyndetic nature of pairing within and between the B and C genomes. In the F 2 generation, a high percentage of plants resembling B. juncea type and transgressive segregation for many characters were found.