Physiological quality of castor bean seed genotypes stored at two temperatures

Abstract

Environment and storage time influence stored seed quality, especially for oilseeds such as castor beans because they have a high lipid content and are more prone to deterioration. This study evaluated the physiological quality of seeds from three castor bean genotypes stored at 10 and 20°C for 300 days. The experimental design was completely randomized, with 4 replications, in a 2 x 6 (2 temperatures x 6 storage periods) split-plot design. The seeds were placed in low-density polypropylene bags and stored in climatic chambers at 10 and 20°C, in which the temperature and relative humidity were registered. Physiological quality (germination, germination rate index, emergence, rate of emergence, electrical conductivity and accelerated aging) were evaluated at baseline and after 60, 120, 180, 240, and 300 days of storage. Castor seeds of genotype EVF 106 showed better physiological quality when stored at 10°C. Castor seeds of genotype EVF 701 could be stored at 10 and 20°C for 300 days. Castor seeds of genotype EVF 712 presented reduced physiological quality during their 300 days in storage, regardless of temperature.

Studies on the Germination and Emergence of Castor Seedlings

“…The seed sample used in this study had a low number of very light seeds, because it was previously selected for commercial purposes, and the few remaining light seeds (2 out of 200) were assumed to be aborted and were discarded. However, it should be noted that very light seeds are clearly of low quality, and they can hardly germinate because they are aborted and have little or no reserves stored [34,38,52]. For that reason, the influence of the seed weight found in this study is only valid if aborted seeds are sorted out.…”

“…The optimal temperature for castor seed germination was found to be near 31 °C (Figure 3). It should be emphasized that most studies on castor seed germination follow the suggestion of standardized tests for quality purposes and incubate the seed at suboptimal temperatures-alternating 20/30 °C or in the range from 25 to 28 °C [3,8,[13][14][15]17,[38][39][40]. Although the procedures for quality assessment need to be standardized, experiments on castor seed germination searching for agronomical performance, vigor, or biological meaning could find better results if they adopt temperatures close to the optimal for this tropical plant species.…”

Mechanical Harvesting of Castor Bean (Ricinus communis L.) with a Combine Harvester Equipped with Two Different Headers: A Comparison of Working Performance

“…Clearly, approximately 80% of the harvested seeds require further processing before being suitable for either storing or direct oil extraction. Storing damaged seeds can trigger high loss in quality of castor oil [31,32]. This, eventually, leads to high production costs that negatively affect the economic sustainability of the whole supply chain [33].…”