Broomrape as a Major Constraint for Grass Pea (Lathyrus sativus) Production in Mediterranean Rain-Fed Environments

Grass pea (Lathyrus sativus) is an annual legume crop that is currently underutilized but has the potential for reintroduction into Mediterranean rain-fed farming systems. In this study, we compared the adaptation of breeding lines in multi-environment field testing, which had wide variation for precocity, grain yield and broomrape infection. Heritability-adjusted genotype plus genotype-by-environment interaction (HA-GGE) biplot and non-metric multidimensional scaling (NMDS) were performed to determine the effect on genotype (G), environment (E) and G × E interaction on grain yield, precocity and broomrape infection. Precocity was associated with reduced broomrape infection, and this with increased grain yield. Step-wise regression analysis revealed that the broomrape infection had the highest influence on grain yield, whereas precocity had a lower effect. Rain and humidity and mild temperatures before and during flowering were the climatic factors most influential on broomrape. Accessions with a shorter growth cycle suffered lower broomrape infection and were more productive in the environments with a high broomrape incidence. Accessions with longer growth cycle suffered overall higher broomrape infection and were therefore more productive in the environments with low or moderate broomrape incidence.