Source - sink relationship in crop plants

If the sink is small, the yield cannot be high, and even if the sink is large the yield cannot be high if the source capacity is limited. This study examines the nature of sources and sinks (their mechanics, dynamics, interactions, and interdependence) and suggests research directions for maximizing yield through agronomic manipulations of source and/or sink. Source/sink limitations are illustrated by examples of modern cultivars of rice, sorghum, tomato, etc. In rice, the source appears to be the major limitation to higher yields in tropical and subtropical climates, while sink is the prime limiting factor in temperate climates. Includes charts, illustrations, and references (1929-85). (Author abstract, modified)