Development of SCAR markers linked to a gene controlling absence of tannins in faba bean

Faba beans are inexpensive, nutrient-dense sources of plant protein, but anti-nutritional factors such as condensed tannins reduce the biological value of their protein. Two recessive genes, zt-1 and zt-2, control the absence of tannins in faba bean seeds and also determine a white flower character on the plant. However, crosses between them produce coloured F1 plants with tannins that contaminate the crop. Therefore, it is important to identify the gene present in all tannin-free cultivars and gene bank accessions to enable breeders to choose appropriate genitors for their crosses. The aim of this study was the identification of markers linked to zt-1, one of the genes governing free tannin content in faba bean. A segregating F2 population derived from the cross between the coloured flower and high tannin content genotype Vf6 and a zt-1 line was developed and characterized phenotypically. Bulked Segregant Analysis (BSA) was used to identify Random Amplified Polymorphic DNA (RAPD) markers linked to the zt-1 gene. Four RAPD loci (OPC5551, OPG15600, OPG111171 and OPAF20776) showed polymorphism between the contrasting bulks. The markers were sequenced to develop specific Sequence Characterised Amplified Regions (SCARs). Amplification of SCC5551 produced a single product which was only observed in the white flowered and zero tannin content genotypes, whereas SCAR SCG11 1171only produced a band in F2 plants with coloured flower and high tannin content. SCARs SCC5551 and SCG111171 were tested for their applicability for routine screening in 37 faba bean genotypes differing in flower colour and tannin content. SCC5551, allowed the prediction of the zt-1 genotypes with a 95% of accuracy, underscoring the potential of this SCAR marker as a cost-effective tool for MAS in large faba bean breeding populations. © 2006 Springer Science+Business Media B.V.

This study was funded by the grants PETRI 95-0682-OP and INIA RTA04-067 from the Spanish Science and Technology Ministry and by the European Community project EUFABA QLK5-CT2002-02307. N. Gutierrez acknowledges a fellowship from IFAPA-CICE, Junta de Andalucía. CM Avila acknowledges financial support from the Spanish Ministerio de Educación y Ciencia (‘Juan de la Cierva’ program)

Peer reviewed