Objective/Hypothesis: Protein quality in common bean is limited by the suboptimal levels of sulfur-containing amino acids, methionine and cysteine. The germplasm line SMARC1N-PN1 lacks major seed storage polypeptides. This leads to increased total cysteine (up to 70%, mol per seed weight) and methionine content (about 10%) and decreased levels of the non-protein amino acid S-methylcysteine. The objective of this work was to generate germplasm lines with similar characteristics with adaptation to Manitoba. Methods used: A cross was made between SMARC1N-PN1 (S) and the navy bean cultivar Morden003 (M) to generate a population of 185 recombinant inbred lines. Protein profiles classified the lines into four groups according to genetic inheritance of phaseolin and lectin. Single nucleotide polymorphic markers enabling to track phaseolin deficiency were validated using a Kompetitive allele specific PCR assay. Lines were tested under field conditions and their amino acid concentrations were evaluated along with protein digestibility using a pH drop assay.
Results: Two SS lines were recovered having a stable protein profile, 2-37 and 3-84. Line 2-37 had a 37% increase in protein digestibility corrected amino acid score as compared with parental cultivar Morden-003. Preliminary results indicated a 60% increase in protein solubility at neutral pH for the storage protein deficient line.
Conclusions: the 2-37 line could be used to develop a dry bean cultivar having improved protein quality.