AbstractSelection for yield in early generations is difficult, mainly due to a shortage of seed. In the breeding company Fr. Strube the breeder uses three‐way crosses and first selects for yield between F2′‐derived lines in the F4′. The generations are called F1, F2′, etc., because the first generation is already segregating. The efficiency of this selection was checked in the F5′ and F6′. For this purpose F3′‐derived progenies, corresponding to poor and good yielding bulks in F4′, were selected. In later generations the average yield of the group of strains with good yield in the F4′ was 4 (F5′) and 3 (F6′) higher, respectively, than the mean of the strains with low yield in the F4′. Strains with very low yielding potential can easily be discarded in the F4′. The risk of discarding lines with a very high yield is minimal. Selection for yield in the F4′ was as effective as in the F5′. The importance of testing F2′‐derived bulks in the F4′ is not only based on the assessment of yield but also on the possibility of reliable intensive selection through recording visual characters (height, resistance against diseases) in a second environment in
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