Inheritance of legumin and albumin contents in a cross between round and wrinkled peas

Legumin and albumin are the fractions of pea seed proteins preferred to vicilin because of their high sulfur amino acid contents. The joint inheritance of legumin and albumin contents was studied in a cross between to contrasting lines of peas - one with high legumin and low albumin, and the other with low legumin and medium to high albumin. Single seed determinations were made in the parental, F1; F2 and backcross generations using rocket immunoelectrophoresis. In the non-segregating generations (P1, P2 and F1), legumin and albumin contents were negatively correlated (r=-≅0.50). The estimates of correlation coefficients in the segregating generations (F2, BC1 and BC2) were also about -0.5. However, the two estimates based on the round and on the wrinkled seeds separately in the F2 generation were not significantly different from zero. At least four individual round F2 seeds showed the desired recombination of high legumin with high albumin indicating that the unfavorable correlation can be broken. In this cross legumin content showed predominantly additive genetic variation whereas the dominance variance was the largest component for albumin content. A combined "relative sulfur index", proposed as a convenient measure for selection, showed a narrow sense heritability of 47%. In general these results support the view that sulfur amino acid content of peas can be improved by breeding, but that the required selection regime must take both legumin and albumin content into account.