Enhancement of genetic diversity in canola-quality Brassica napus and B. juncea by interspecific hybridisation

Abstract

Reciprocal crosses were made between Brassica napus cv. Mystic (canola) and B. juncea JN29 (near canola quality). The F1 hybrids were selfed and backcrossed in all possible combinations to parent plants. The greatest number of selfed fertile progeny were obtained when Mystic was the maternal parent, and its F1 was most successful in backcrosses to Mystic or JN29 as maternal or paternal parent. The predominant morphological type of fertile progeny was B. napus, but several B. juncea morphological types occurred in F2 and BC1-derived lines. F2 : 3 and BC1S0 : 1 progeny showed transgressive segregation for agronomic and seed quality traits in two contrasting field environments. Several of the B. juncea-type progeny had improved seed quality (lower total seed glucosinolates and higher % oleic acid) over the B. juncea parent. Selfing of interspecific hybrids between canola-quality B. napus and B. juncea has the potential to greatly enhance genetic diversity in canola-quality progeny of both species, without the loss of donor alleles that normally occurs with repeated backcrossing.