Research in Plant Sciences

Epidemiology of Cassava Mosaic Disease and Control Methods in the Central African Republic

2026-01-03

Cassava is the leading crop in the Central African Republic. Since 2000, severe mosaic symptoms have been observed on cassava in this country. Thus, surveys carried out between 2005 and 2011 showed an incidence of mosaic of 85% with the presence of ACMV and the severe Ugandan strain of EACMV-UG diagnosed. The surveys showed more than 50% of the plants were co-infected by the two species and the viral synergy increased the severity of the disease and made it possible to estimate 50% of harvest losses and to demonstrate that the main factor in the spread of the disease was the deplorable phytosanitary state of the cuttings used by farmers for replanting plots with 79% of cuttings contaminated. Subsequently, several studies were conducted to identify disease control measures. This is how; A varietal selection was carried out between 2008 and 2011 and resulted in the identification of 14 mosaic-resistant varieties with high yield potential and better meeting the population's culinary habits. Our work revealed through Farmer Field Schools that conventional technical itineraries double cassava production unlike traditional practices. In the strategy of sanitation of plant material by the therapy technique, contaminated cuttings of a local variety susceptible to mosaic were heat-treated in hot water baths between 41°C and 51°C for 30 minutes and then evaluated in the open field over a period of 12 months until harvest. Our results show that 49°C represents the optimal treatment temperature, without negative impact on the regeneration capacity of the cuttings, and for which we observed the highest tuber yield (4.7 kg / plant), equivalent to untreated cuttings from asymptomatic plants (4.6 kg / plant). Our studies have shown that regeneration of infected cuttings in a high-temperature room (37°C to 40°C) for 15 days followed by meristem culture effectively disinfects the contaminated plant material. The combination of thermotherapy and meristem culture techniques is an effective way to disinfect infected plant material. The popularization of resistant varieties and the sanitation techniques tested in this study constitute an effective means of disease control.

Phytoplankton Community of the Fatala Estuary (Republic of Guinea)

2026-01-19

The study of the phytoplankton community was conducted during the dry, intermediate, and rainy seasons between December 2018 and December 2019 in order to assess phytoplankton diversity. A 2.5-liter Van Dorn plankton bottle was used for sampling. A total of 2,629 specimens belonging to 11 taxa were collected. These taxa are distributed across the following eleven (11) classes: 54 Cyanophyceae, 72 Euglenophyceae, 50 Conjugatophyceae, 143 Chlorophyceae, 29 Dinophyceae, 28 Rhodophyceae, 55 Zygnematophyceae, 18 Xanthophyceae, and 1,936 Diatoms or Bacillariophyceae distributed across 47 genera. The Diatom class was dominated by Coscinodiscus granii and Cyclotella spp. (representing more than 1.90% and 1.86% of the total species, respectively). The study of seasonal variation of physicochemical parameters on the phytoplankton community in the Fatala estuary showed that the correlation matrix performed to evaluate the relationships between physicochemical and biological parameters revealed significant correlations only between temperature and the phytoplankton community, total diatoms, and pennate diatoms (r = 0.361; 0.356; 0.384, respectively) (p < 0.05). In contrast, salinity was significantly correlated, positively with temperature (r = 0.443) and negatively with nitrates and nitrites. This study provided the first qualitative and quantitative inventory of the phytoplankton community of the Fatala estuary prior to mining activities of the Boffa1 project. These results serve as a reference for future monitoring of the phytoplankton community and for the development of appropriate measures to ensure better protection and sustainable exploitation of the aquatic resources of this estuary.

Optimizing Cultivation Parameters and Bioactive Potential of Curcuma longa L. in Non-Traditional Climates

Bipul K Biswas, Nichole Mullen, Arthur Roberson — 2026-01-30

This study evaluated the impact of various soil amendments on turmeric (Curcuma longa) biomass production, curcuminoid concentration, and subsequent antibacterial efficacy. Twenty soil treatments, including a control, were applied to raised beds. Post-harvest, total biomass was recorded as fresh weight. Curcumin content was quantified via High-Performance Liquid Chromatography (HPLC), and the resulting extracts were screened for antibacterial activity against Bacillus cereus and Escherichia coli. Soil amendments applied at a nitrogen concentration of 300 kg/ha significantly enhanced turmeric biomass compared to other treatments. Furthermore, the treatments influenced the secondary metabolite profile, with specific amendments yielding peak curcumin concentrations. These findings suggest that optimized nitrogen-based soil amendments not only maximize physical yield but also enhance the bioactive potential of turmeric, providing a strategic approach for high-quality pharmaceutical-grade cultivation.