Cultivar and environmental impacts on protein and mineral concentrations in peas (Pisum sativum L.)

Pea (Pisum sativum L.) grain contains abundant protein, starch, and minerals. However, there are obstacles to growing peas that achieve consistently high protein and mineral concentrations. Seven pea cultivars were planted at seven locations with contrasting soils and environmental factors to evaluate the genetic and environmental effects on pea yield and quality. Correlations and principal component analyses (PCA) were performed to correlate pea grain yield and protein with mineral concentrations in pea grain and soil. Significant cultivar x location interactions were observed on pea grain yield but not on pea grain protein concentration. Some cultivars demonstrated more sensitivity to the environment than others in terms of grain yield potential and stability. The lack of a cultivar x location interaction for pea grain protein concentration indicates consistent genetic control of this quality parameter. Although there was a negative relationship between pea grain yield and protein concentration at the cultivar level at each environment, this correlation became weaker while pooling the data from all environments (site-years) due to the confounding effect from environments. Pea grain mineral concentrations were significantly affected by cultivar and location, but location generally affected the mineral levels more than cultivar. Grain mineral nutrients, especially macronutrients, were highly correlated with soil minerals. The three distinct clusters formed in the PCA indicate mega environments that determine pea grain yield and quality, and understanding the mega environments in combination with improved soil fertility management may represent the most effective means of increasing pea grain yield, protein, and targeted mineral levels.