Breeding foxtail millet (Setaria italica) for quantitative traits after interspecific hybridization and polyploidization

Abstract

An interspecific cross was carried out between the cultivated foxtail millet, Setaria italica, and its wild relative the green foxtail, S. viridis. Quantitative characters (19 descriptors of morphology and reproduction) were studied using the F1 F2, and F3 generations. Moreover, this F2 was compared with the tetraploid F2 obtained from a colchicine-induced F1. The multivariate analysis of the diploid F2 showed two complex associations of characters: one concerning developmental traits (organs dimensions and flowering) and the other dealing with taxonomical characteristics (tillering, seed shedding, and seed weight). The tetraploidization resulted in a shift in characteristics towards the crop species, especially a twofold increase in seed weight. Nonadditive effects were found for most characters, except for the seed shedding, which was found to be encoded by at least four loci. However, cultivated type plants were easily recovered in both the diploid and the tetraploid F2. This demonstrates the potential of interspecific hybridization and polyploidization to improve the crop properties of the foxtail millet. Key words: foxtail millet, polyploid, quantitative inheritance, hybridization (interspecific).