Plant architecture, competitive ability and crop productivity in food legumes with particular emphasis on pea (Pisum sativum L.) and faba Bean (Vicia faba L.)

Plant breeders have developed new plant ideotypes, with modified canopy architecture, in an attempt to increase yield and stability of yield in grain legume crops. Semi-leafless peas, with leaflets replaced by tendrils, have been introduced successfully. Their crop canopy is as efficient photosynthetically as conventional types but far superior in standing ability; the semi-leafless phenotype is a major factor contributing to potentially higher and more stable yields in peas. Completely leafless peas, however, in which stipule size is also greatly reduced, have not proved successful; photosynthetic area is insufficient to produce satisfactory yields at economic planting densities. In conventional indeterminate faba beans, much of the inherent yield variability is attributed to intra-plant competition for photosynthate. It was envisaged that more determinate types would partition photosynthate to yield components with greater efficiency; this has not been realized in practice. Canopies of fully determinate (“topless”) faba beans are physiologically and agronomically inferior. Short-strawed spring beans, however, have demonstrated yield improvements. Lentils and chickpeas are relatively new crops on the Canterbury Plains of New Zealand. Lentils appear to be more suited to conditions than chickpeas because when sown early, crops develop larger crop canopies, intercept more radiation, and convert absorbed radiation into dry matter more efficiently.