Trait associations and genetic variability in field pea (Pisum sativum L.): Implications in variety development process

Background and objectives Research and breeding for pea protein extraction are likely to play an important role as the demand for pea protein increases. Developing pea cultivars with high protein concentration could be a top breeding priority. Identification of the traits to select for and understanding the relationships between them will optimize the breeding process. Protein was extracted from 26 green and 30 yellow pea genotypes grown in four and two environments, respectively. Findings During dehulling/decortication, approximately 15.6% of the pea seed was removed as seed coat, with a low of 10.1% and a high of 20.4%. The protein concentration of split pea flour varied between 18.9% and 29.3%. Split pea had 1.4 percentage point higher protein than the whole pea. Flour protein concentration varied among environments, with Fairfield, WA having the highest mean values. Protein isolate yield ranged from 14.8% to 21.1%, with a mean of 17.8%. Protein recovery from split pea flour ranged from 57.4% to 76.3% across all pea types, with a mean of 65.7%. On average, about 61.6% of the initial sample ended up in the starch-rich byproduct fraction. The remaining 20.6% the initial samples lost as soluble material during the extraction process. Correlation analysis indicated that flour protein concentration was positively correlated with protein isolate yield and purity but negatively with yield of the starch-rich byproduct. Conclusions Increasing protein concentration leads to increased protein yield and reduced the loss as byproduct during the extraction process. Further studies are required to understand the relationships of protein isolate yield and purity with functional properties of protein. Significance and novelty The associations among traits imply that the flour protein concentration could be used in the selection process. Increasing protein concentration could be one key input in proving pea cultivars for protein isolation.