The Journal of Agricultural Science




CROPS AND SOILS

Genetic variability for feeding value of faba bean seeds (Vicia faba): Comparative chemical composition of isogenics involving zero-tannin and zero-vicine genes


G. DUC a1c1, P. MARGET a1, R. ESNAULT a2, J. LE GUEN a2 and D. BASTIANELLI a3
a1 Institut National de la Recherche Agronomique, Unité de Recherche en Génétique et Amélioration des Plants, BV1540-21034 Dijon Cédex, France
a2 Institut National de la Recherche Agronomique, Station de Génétique et Amélioration des Plantes, BP29-35650 Le Rheu, France
a3 Union Nationale Interprofessionnelle des Plantes Riches en Protéines, 12 avenue Georges V, 75008 Paris, France

Abstract

In a preliminary experiment, 74 faba bean genotypes including winter genotypes (autumn-sown) and spring genotypes (spring-sown) and isogenic population pairs (tannin-containing v. tannin-free and vicine/convicine-high v. vicine/convicine-low), were analysed for the chemical composition of their seeds. A large variability was found for the main constituents (starch, protein and fibre). Autumn-sown genotypes contained 2·3% less proteins but 2·5% more starch in the seed dry matter (DM) than spring-sown genotypes. The vc gene, which lowers the vicine and convicine contents, did not significantly modify the main seed components in the isogenic comparisons. The zt1 and zt2 genes, which eliminate condensed tannins in the seed coats, lowered by 2·1% the proportion of the seed coat in the DM. In the isogenic comparisons, the zt2 gene had a stronger effect than zt1 in reducing the total seed fibre and increasing the protein content.

In a second experiment, from the original 74 genotypes, 12 contrasted genotypes were selected and multiplied for animal nutrition trials. Their chemical analysis confirmed the variability between the faba bean categories observed in Expt 1, but detailed chemical analyses illustrated the variability in amino acid, fatty acid, amylose and oligosaccharide composition, trypsin inhibitory activity, condensed tannins, lectins and phytic phosphorus contents.

(Received January 8 1999)


Correspondence:
c1 To whom all correspondence should be addressed. Email: duc@epoisses.inra.fr


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