Field pea breeding for integrated adaptation to biotic and abiotic stresses in Mediterranean rainfed agrosystems

Abstract

Context: Improving adaptation of field pea (Pisum sativum L.) to Mediterranean rainfed systems requires considering the combined effects of climate factors and key biotic constraints, including parasitic weeds like broomrape (Oc) and foliar diseases such as powdery mildew and Ascochyta blight. However, the combination of these stresses remain insufficiently understood. Objectives: To quantify and compare the performance, stability, and response to stresses of novel pea breeding lines; to identify agronomic and climatic predictors of yield; and to guide pea breeding for adaptation to Mediterranean rainfed systems. Methods: In this study, nine advanced pea breeding lines developed under the IAS-CSIC breeding programme were compared with five commercial cultivars in multi-environment trials across three seasons. Agronomic, phenological, and disease-related traits were assessed and analysed using Genotype×Environment (G×E) and multivariate approaches to address yield stability and to inform selection under biotic and abiotic stresses. Results: Among the biotic constraints, Oc had the strongest negative impact on grain yield. Higher levels of Oc parasitism were favoured by spring rainfall and high temperatures, thereby altering crop–environment interactions. IAS-CSIC breeding lines showed superior resistance to Oc, with approximately 50% fewer Oc shoots per plant than commercial cultivars. Consequently, they achieved higher yields in Oc-infested environments (1742 vs 743 kg ha⁻¹). They also showed higher yields in Oc-free environments (3435 vs 2803 kg ha–1), highlighting consistent productivity and successful adaptation to Mediterranean rainfed systems. In Oc-free environments, abiotic-stress indices indicated that several breeding lines showed better yield maintenance than commercial cultivars under drier, hotter spring conditions. Rainfall showed beneficial or detrimental impacts on yield depending on the presence or absence of Oc. Several agronomic traits (i.e., plant height, crop appearance, lodging, and thermal time during pod filling) were consistent predictors of yield. The impact of powdery mildew on yield was limited under the studied conditions with several lines showing complete resistance. Multi-trait selection enabled the identification of breeding lines combining improved Oc resistance with yield stability and no trade-offs in agronomic traits or in response to other biotic stresses, particularly Cartujano, Chicana, and Pepapea. Conclusions and significance: Altogether, our results provide practical recommendations for growers in the Mediterranean region and methodological guidance for breeders. These findings illustrate the utility of combining resistance introgression, multi-trait selection, and trait-informed modelling as complementary strategies. This integrative framework may also support genetic improvement for adaptation to environments distinct from the original breeding context and exposed to diverse, and novel stresses.