Quantitative studies on the cotyledonary proteins in the genus Pisum

Abstract Forty‐five lines of peas including primitive or wild forms, field peas, and round and wrinkled garden peas, were grown under uniform conditions and the seeds examined for variation in protein characteristics likely to influence nutritional value. The characters measured were crude protein, extractable protein, globulins and albumins, the percentages of legumin, total sulphur and protein sulphur, carbon: nitrogen and nitrogen: sulphur ratios. The extractable protein was separated quantitatively into an albumin fraction (20–35%) and a globulin fraction (legumin and vicilin). Without exception lines high in albumin content were low in legumin content (correlation coefficient r = −0.757). As both the albumin fraction and legumin are rich in sulphur amino acids, this negative correlation has important implications for attempts through plant breeding to improve the nutritional quality of legume seed proteins, by increasing the sulphur amino acid content. Total sulphur was not correlated with any other protein character.