Does a mixture of pea varieties with different leaf morphology improve crop performance?

Crop diversification in space and time is a key component in the design of resource -efficient cropping systems with reduced dependency on synthetic inputs. A well - known example of crop diversification is the practice of intercropping, i.e. growing two or more crops together in the same field. Intercropping grain legumes and cereals in low-input systems makes use of complementary acquisition of light, water and nutrients to enhance the crop’s resource use efficiency and competitiveness against weeds. Within-species diversification in variety mixtures may also increase yield stability, via e.g. complementary tolerance to abiotic or biotic stress. As part of the European LEGATO project, our study has investigated whether a mixture of pea (Pisum sativum L.) varieties with two types of leaf morphology can increase the legume crop’s standing ability and competitiveness against weeds. The pea varieties Dukat (normal-leafed) and Partner (semi-leafless) were grown as single varieties and variety mixtures with and without a wheat intercrop in field experiments at four locations in Europe: Serbia (Novi Sad), Sweden (Alnarp) and France in central (close to Paris) and southern (Toulouse) regions. Lodging, weed biomass and crop/intercrop grain yields were recorded during two growing seasons per location. The results showed that a variety mixture of pea can combine the beneficial traits of the single varieties with maintained legume grain yield relative to the highest-yielding variety. However, the benefits in terms of weed reduction and standing ability were not as strong in variety mixtures as in pea-wheat intercrops, which remained the most efficient mixtures