Fig. 6.
A sample of tracing elite yield alleles in the pedigree of NN1138-2 cultivar family (Adapted from Zhang et al. 2009b). * P: pedigree ancestor. The numbers 1, 2, ~21 are codes of cultivars, not the same as in Fig. 5; among them cultivars 3, 6, 11 and 20 having high yield potential more than 2830 kg km−2, while cultivars 4, 5 and 9 having low yield less than 1350 kg km−2. ➀, ➁, ➂ and ➃ represent the breeding cycles in the cultivar family. On the four loci where NN1138-2 having superior alleles, its derived cultivars may have the allele(s) same as NN1138-2, but its source may be different, some inherited directly from NN1138-2 (green cell), some inherited from other parental materials (red cell), some from both NN1138-2 and other parental materials with the same allele (blue cell) and some from other cases (yellow cell) according to tracing the cultivars’ pedigree. By genetic dissection combined with pedigree analysis, some loci can be recognized as identical by descent (green cell with star). In addition, there appeared superior alleles on other loci in the derived cultivars which should come from the other parents in the family history.