Agronomical traits, seed color and protein content of protein pea (Pisum sativum L.) cultivars grown in European conditions

Abstract

Protein pea (Pisum sativum L.) is a protein-rich legume (up to 33% of seed protein). Using pea in the human and animal diet provides one of the best solutions for the long-term lack of plant-based protein. Although soybean is one of the primary plant protein sources, the advantage of growing pea is their wider geographical area and colder climates adaptability. The objective of this study was to determine the impact of different agroecological conditions in 64 protein pea cultivars on seed protein content and agronomical traits related to seed yield. A two-year trial on two European sites (Serbia and Belgium) was done using an augmented block design. The average temperatures and total precipitation amount during the vegetative period (March-August) in Serbia trials were 18.4 °C and 381.4 mm for 2019 and 18.1°C and 488.9 mm for 2020, and in Belgium trials 14.9 °C and 268.9 mm for 2019 and 14.7°C and 184.6 mm for 2020. Agronomical traits (flowering duration FD, plant seed yield PSY, thousand seed weight TSW, and seed per pod SPP) were determined using ten plant samples, while seed protein content (SPC) was determined using near-infrared spectroscopy (Table 1). Statistically significant differences between localities were determined by T-test, and Pearson's correlation coefficients were determined between traits. Multivariate analysis was performed based on the examination of mean values of traits for both localities, in order to investigate the population structure of 64 pea genotypes differing in color and seed type. Significant positive correlation was observed between TSW and PSY (0.60), and between SPP and SPC (0.25). A significant negative correlation was determined between SPC and TSW (-0.66) and between SPC and PSY (-0.41). The results of multivariate analysis based on seed color show the separation of pigmented seeds from mixed non-pigmented seeds by the first axis (35.9%) and yellow non-pigmented seeds by the second axis (17.9%), with no clear grouping in relation to seed type (smooth, wrinkled, dimpled). The similar values of the main agronomic traits that affect the yield confirm the great ability of protein pea to adapt to different agroecological conditions.