Choice of methods and indices for identifying the best parentals for synthetic varieties in faba bean

摘要

The aim of this study was to determine the efficiency of different evaluation methods and indices for the prediction of the best parentals for the development of a synthetic variety of the faba bean (Vicia faba). Top-cross and poly-cross methods intwo modalities (1 and 3 seed per hill) were compared using 4 indices. Indices were evaluated for seed number and yield per plant. Outcrossing rates were estimated using 7 isoenzyme markers, the mixed mating model and the multilocus method. Indices were compared in terms of similarity in their ranking of parental genotypes, assuming that the most consistent index is that which gives the highest similarity in ranking over all the designs. There were no differences among the designs in terms of outcrossingrate. However, there were differences among parental lines and the level of outcrossing of a particular parental line depended on the spatial arrangement in the field. Ranking of parental lines based on both modalities of the poly-cross design was similar for all the indices used, suggesting that the evaluation of outcrossing in poly-cross designs might be unnecessary. However, indices that take into account variability in outcrossing gave similar ranking of parental lines over both methods and modalities. The results underline the importance of taking into account the variability in outcrossing rate when developing synthetic varieties in partially allogamous crops.