Diversity in a pea (Pisum sativum) world collection for key agronomic traits in a rain-fed environment of Southern Europe

The marked underutilization of pea ecotype and old cultivar genetic resources need be reversed by producing information on elite germplasm and diversity patterns for key agronomic traits. This study generated such information for a world collection of 223 ecotypes or old cultivars of P. sativum subsp. sativum subdivided into 19 regional pools (each represented by 9-15 entries) and one reference pool of 11 locally-adapted varieties from France, Spain and Germany. The collection was evaluated for grain yield, seed protein content, straw biomass, phenology and other agronomic and morphological traits in a spring-sown, water-limited environment of Northern Italy. Variation within ecotype/old cultivar germplasm pools was at least two-fold greater for seed size and protein content and seven-fold greater for other traits relative to variation between pools, and was particularly large within pools from Central Europe, Near East and United Kingdom. The traditional germplasm, compared with improved variety material, tended to display higher dry grain yield (1.11 vs. 0.85 t/ha) and straw biomass, later crop maturity, smaller seed, and similar protein content. Traditional germplasm from Central Europe combined outstanding grain yield and total biomass with high seed protein content. High grain yield characterized, inter alia, the germplasm pools from Ukraine and Spain, the latter also featuring high protein content. Several ecotype/old cultivar accessions out-performed (P < 0.05) the best-ranking varieties for grain yield or protein content. Patterns of phenotypic variation were poorly related to geographic origin of germplasm pools, while highlighting the distinctness of improved variety germplasm.