Browsing by Author "Kilasi, Newton"

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Breeding rice for salinity tolerance and salt-affected soils in Africa
(UK Limited, trading as Taylor & Francis Group, 2024) Mheni, Nafeti Titusi; Kilasi, Newton; Quiloy, Fergie Ann; Heredia, Maria Cristina; Bilaro, Atugonza; Meliyo, Joel; Dixit, Shalabh; Msolla, Susan Nchimbi
Salinity is one of the main factors that limit rice production globally. In Sub Saharan Africa, soil salinity has affected many countries. Understanding the available screening techniques and the mechanisms of salinity tolerance in rice is very important for dealing with soil salinity problem. This review summarizes the extent of soil salinity problems in some of the affected African countries and the available salt stress-tolerant rice genotypes. The problems, challenges and opportunities of salt-affected soils in Sub Saharan Africa are thoroughly described in this review, which also looks at breeding techniques which have been used for developing rice cultivars adapted to salt stress. Among the best option to deal with salinity-related problems is through the use of tolerant rice varieties, as many other available management approaches are not economically feasible for small-scale farmers. Also, the review discusses different approaches, both conventional and molecular breeding approaches that have greatly enhanced the current rice breeders’ toolboxes for developing salt-tolerant rice varieties. The review suggests that more efforts are required to leverage conventional breeding with molecular techniques for speedy identification of tolerant cultivars, useful markers and quantitative trait loci (Qt Ls). It is recommended that it is crucial to reinforce collaborative efforts and continuous investment in research, capacity building, and knowledge sharing for developing improved rice tolerant cultivars in order to fully address salinity problems in African.
Effects of antifungal plant extracts on improving maize seedling emergence and plant growth
(International Seed Testing Association, 2022) Erasto, Rehema; Madege, Richard Raphael; Kilasi, Newton
Maize seeds are usually contaminated with seed-borne fungi which cause seed deterioration and seedling death. Seed treatment using chemical fungicides is a common practice, although fungicides can reduce seed longevity and lead to residues, resistance, and environmental pollution. This study was conducted to determine the effects of plant extracts (PEs; Azadirachta indica, Coffea Arabica, and Zingiber officinale) on seedling emergence and seedling vigour of certified (CS) and farmer-saved (FSS) seeds of maize. Seeds treated with water-extracted PEs had significantly higher seedling emergence with 85.8% and 61.7% for FSS and CS, respectively, while ethanol-extracted PEs had 6.7% and 7.5% seedling emergence for FSS and CS, respectively. The minimum mean number of days to the first emergence was less for seeds treated with water-extracted PEs (3.0 and 3.3 for FSS and CS, respectively) than those treated with ethanol-extracted PEs (6.3 and 7.0 for FSS and CS, respectively). According to this study, water-extracted PEs are potential candidates in seed treatment, because they have fewer adverse effects on seedling emergence and vigour. Although other studies mention PEs extracted using organic solvents to be the best, the study’s recommendation is to ensure that organic solvents are completely removed from PE solutions before using them.
Prevalence and Management of Phytopathogenic Seed-Borne Fungi of Maize
(MDPI, 2023) Erasto, Rehema; Kilasi, Newton; Madege, Richard Raphael
Seed-borne fungi are solemn and deleterious pathogens capable of causing significant losses of quantity and quality losses in maize seeds and seedlings. They infect the crop at all points of the production chain from farms to stores. A yield loss of up to 50% can be encountered. Currently, chemical control of the disease is being implemented, though it is accompanied by several negative effects. This study aimed at identifying seed-borne fungi of maize and effective management options. A deep-freezing blotter method and morphological identification of the fungal species were implemented. The seed-borne fungi detected were Fusarium verticillioides, Aspergillus flavus, Aspergillus niger, Penicillium spp., Rhizopus spp., and Curvularia spp. However, in farmer-saved seeds, fungal incidences were significantly higher (p < 0.01) than in certified seeds. To identify more effective management options, the efficacy of water and ethanol-extracted bio-fungicides from three plant species, namely, neem (Azadirachta indica), ginger (Zingiber officinale), and coffee (Coffea arabica) were evaluated. From in vitro assays, ethanol-extracted bio-fungicides have a 100% inhibitory effect on fungal growth, whilst the inhibitory effects of water-extracted bio-fungicides are 55.88% (Azadirachta indica) and 46.31% (Zingiber officinale), followed by 5.15% (Coffea arabica). For the case of an in vivo assay, maize seeds treated with water-extracted bio-fungicides have higher seed germination and seedling vigor percentages. For germination, seeds treated with water-extracted bio-fungicides have higher percentages (neem and ginger (90%) followed by coffee (72.5%)) than ethanol-extracted bio-fungicides (neem (0%), ginger (2.5%), and coffee (0%)). A similar observation is made for seedling weight. Therefore, the tested water-extracted bio-fungicides can be used in treating seeds before sowing them. Further studies on effective methods of extracting bioactive compounds, and improving their shelf life, are recommended.