Year: 2012
Type: dissertation
Abstract: A series of studies was made on the influence of environmental factors on the oil yield components and in the seed physiology of castor plants (Ricinus communis L.). The adjustments in oil yield components were used to understand the potential trade-offs in response to changes in the components arising from genetic improvement and crop management. The number of racemes per plant was found to be the most plastic yield component. A plant with few racemes is desired for making easier the mechanization of harvest; however, a plant with limited ability to initiate new racemes is likely to have little plasticity to adjust to the environmental conditions. Understanding the trade-offs associated with each yield component is key for breeding and crop management. In the study of seed physiology, the occurrence of seed abortion and the influence of internal and external factors on the variability in seed weight in the same plant were investigated. Seed abortion was found to be a physiological mechanism related to the adjustment of sink demand. It has a low energetic cost but provides the plant with an increased plasticity to adjust the number of seeds according to environmental condition and source strength. It was also found that seeds in the same fruit or raceme do not seem to compete for limited assimilates from the mother plant. The seed yield in castor plant is apparently limited by source capacity. Then, increasing the source capacity is more likely to result in higher seed yields than increasing the sink size. A literature review was compiled in order to propose a framework for the study of growth and development of castor plants with focus in aspects that can potentially impact castor breeding and crop management. Many gaps in the understanding of castor plants need to receive attention from the scientific community working on this oilseed, and many of those missing links were emphasized. Castor breeding and crop management will benefit from a deeper understanding of how plants respond to environmental factor, agricultural practices, and selection of plants with special traits.
Author: L. S. Severino
Language: English
Subfield: Plant Science
Domain: Life Sciences
SDG: Zero hunger
Open Access status: green
OpenAlex ID: W2263231828