Comparison of some selection procedures and objectives in faba beans (Vicia faba L.). II. Selection for crude protein content

Summary Starting with two heterogeneous F₂ populations, each based on 20 cross combinations, different types of selection were applied for four consecutive selection cycles. Three of the selection procedures involved crude protein content (CP) and are presented in this paper. They were selection for high CP (HP), selection for low CP (LP) and independent culling levels selection for high CP and an index for seed yield per plant (ICL). For ICL-selection the attention is focussed on CP in this paper.For all three selection procedures, predicted and realized responses were calculated and expressed as percentage of a corresponding random population. The selection intensities (i) differed over selection procedures and generations. Differences in i between HP and LP within generations were mostly of minor interest. The response to HP-selection was slightly higher than to ICL-selection, but this may be due to the higher selection intensity exerted with the former method.HP-and LP-selection showed some remarkable differences, which were interpreted as a tendency towards partial dominance of high over low protein content. The total response to HP-selection gradually increased, whereas LP-selection yielded the total response largely after only one cycle of selection. The predicted response showed a tendency towards overestimation in the case of HP-selection and to underestimation in the case of LP-selection.Selection for high protein yield through CP seems to be feasible, although improvement of yield stability may eventually be more necessary. As no consistent correlation, either positive or negative, between SYP and CP could be detected, selection for either of these characters may be considerd independently of selection for the other one.