Fig. 5

Using yield breeding value estimates of plant genetic resources (PGR) to initiate pre-breeding programs in wheat. (a) Kernel density distribution of yield breeding values (Mg/ha) for 707 PGR. Breeding values were estimated using yield data of ‘Elite × PGR’ F₁ hybrids from 22 field experiments conducted between harvest years 2016 and 2020. Based on preliminary data from 2016, 13 PGR with superior breeding values were used as male parents in two- (Elite₁ × PGR) and three-way (Elite₂ × [Elite₁ × PGR]) crosses involving 11 adapted elite cultivars. Vertical dashed lines indicate the breeding values of selected PGR estimated across the full set of 22 experiments. (b) After two-stage selection for high leaf health and reduced plant height, 173 advanced F_3:4 PGR-derived progenies tracing back to 32 initial crosses were tested together with 15 elite cultivar checks (black dots) and 16 additional IPK pre-breeding lines (gray dots) in yield validation experiments conducted in two locations during harvest years 2020 and 2021. The best linear unbiased estimations of yield (Mg/ha) computed across validation experiments for the tested material are portrayed and grouped according to each initial cross. The color legend of PGR-derived populations matches that of the selected PGR parents used in initial crosses. Horizontal dotted and dashed lines indicate the yield performances of the best newest cultivar (‘LGCharacter’) and the mostly grown cultivar during the last decade (‘RGTReform’) in Germany, respectively.