A framework for the study of the growth and development of castor plant

A deeper understanding of the growth and development of castor plant (Ricinus communis L.) will be required for the transition from the low input/low yield present scenario to the desired condition of mechanically harvested with high seed yield. The objective of this review was to discuss important aspects of castor growth and development in order to propose a framework for the study of aspects that can potentially impact castor breeding and crop management. Gaps in the knowledge were emphasized. Castor has a slow and cold-sensitive germination that negatively impact crop establishment. The importance of cotyledonary leaves has been poorly studied. Leaf area is very responsive to growing conditions, and factors that influence leaf size and leaf number were discussed. Leaves play a role beyond photosynthesis, particularly on the storage of nutrients and assimilates. Remobilization of stored compounds during leaf senescence is pivotal for seed filling, and this process can impact seed yield in early maturing varieties. Studies on castor root are scarce, despite its importance for plant growth. Some physiological processes of seed development such as seed filling duration and seed growth rate play an important role in the adaptation to different environments and for increasing earliness. Seed abortion is an important mechanism of sink adjustment to environmental conditions which can be explored for increased plasticity. Harvest index is a simple approach that historically has been very useful for increasing seed yield of many crops, and that should be used more often in castor research. Finally, modeling would be an obvious consequence of progresses in the understanding of physiological processes controlling castor plant growth and development.

► A framework for the study of castor growth and development was discussed.
► Gaps in the knowledge were emphasized.
► Topics discussed include leaf area, seed filling, roots, biomass partition, and harvest index.