Location: Sugarbeet and Potato Research
Project Number: 3060-21650-001-038-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Aug 1, 2021
End Date: Dec 31, 2022
(1) Quantify protein variability in pea grain in relation to grain yield across broad rainfall and temperature gradients that span the Northern Great Plains, and (2) Quantify pea protein variation, nitrogen fixation, and protein yield, in response to imposed heat and drought stress.
The study’s overall goal and specific objectives will be accomplished with small plot trials at several locations across the Northern Great Plains. For Objective 1, we will conduct a common pea variety trial at 7 locations spanning a very broad aspect of the Northern Great Plains. The study will be run for 3 years to sample year-to-year differences in regional weather conditions. Soil cores will be taken in 0-6 and 6-24” increments to characterize nutrient availability before final trial planting to avoid highly variable soil conditions. All sites will use granular rhizobium inoculant, and a blend of P-K-S fertilizer will be seed-placed to ensure nutrients do not limit yield or protein response. The trial will have 5 reps in a randomized complete block design. The start and end of the flowering period, as well as physiological maturity, will be recorded. Yield component and grain samples will be taken at maturity to evaluate protein relations and variability. Upper vs. bottom pod samples will be taken at R7 maturity before yield harvest from 10 randomly chosen plants from all plots to compare plant-level variability for pea protein for each cultivar. For Objective 2, a plot trial located near Bozeman, MT will be established to evaluate imposed heat and drought stress effects on pea yield and protein. The four heat stress treatments will each be imposed for three weeks at a time by inducing increased air temperature at (1) ~ 6th node, (2) pre-flower, (3) post-flower, and (4) an untreated control, each paired with and w/o rainout shelters between two contrasting pea cultivars (determinate or indeterminate). The study will total 16 treatment combinations with 4 replications. Growth temperature will be increased by about 3 degrees Fahrenheit via the use of open-top plastic chambers, and rainfall will be decreased by 50% during planned protocol periods via the use of inclined slat structures. Pea plant samples will be harvested at the R1 stage, in addition to reference plants (flax) to determine the amount of nitrogen (N) fixed from atmospheric nitrogen. Plant biomass samples will be dried, ground, and analyzed for 15N and total N via LECO combustion. Grain samples will be analyzed for combustible N and data archived to explore the future development of NIR-protein equations.