Pea

This chapter examines the relationships between water usage and photoassimilate production and growth of peas. A considerable number of investigations on peas have focused on how photoassimilate production interacts with the morphological and physiological characteristics of a genotype and how this relationship is influenced by the cultural and climatic circumstances to which a crop is exposed. Studies on assimilate partitioning in field-grown crop species have paid little or no attention to roots as sinks of photosynthate. Source inadequacy in leafless and semileafless lines is well reflected in slower rates of dry matter accumulation during early seedling growth than in normal-leafed forms. Tendrils of normal-leaved genotypes are much less active in photosynthetic fixation of CO₂ on a dry weight or area basis than companion leaflets or stipules. The importance of continued availability of water to growth and yield of peas under rain fed conditions is well recognized and crops in many areas are accordingly subjected to supplementary irrigation.