Browsing by Author "Grace Nakabonge"

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    Combined Effects of Indigenous Arbuscular Mycorrhizal Fungi (AMF) and NPK Fertilizer on Growth and Yields of Maize and Soil Nutrient Availability
    (Sustainability, 2023-01-25) Abdoulaye Fofana Fall; Grace Nakabonge; Joseph Ssekandi; Hassna Founoune-Mboup; Arfang Badji; Abibatou Ndiaye; Malick Ndiaye; Paul Kyakuwa; Otim Godfrey Anyoni; Clovis Kabaseke; Amos Kipkemoi Ronoh; Joseph Ekwangu
    The excessive application of mineral fertilizers in maize cultivation leads to progressive soil contamination in the long term and increases the cost of production. An alternative to reduce over- fertilization is to perform a partial replacement with microbes that promote nutrition and growth, such as Arbuscular Mycorrhizal Fungi (AMF). A pot experiment which was followed by two field experiments was performed with and without the application of indigenous AMF in combination with five nitrogen–phosphorus–potassium (NPK) fertilization rates (100% NPK = N120P60K60; 75% NPK = N90P45K45; 50% NPK = N60P30K30; 25% NPK = N30P15K15; control = N0P0K0). The objective was to investigate whether the soil application of indigenous mycorrhizal fungi inoculum combined with NPK fertilization can provide higher maize yields and soil-available N, P, and K than chemical fertilization can alone. The greenhouse results showed that the application of AMF with a 50% NPK treatment significantly increased the plant’s growth, root colonization, leaf chlorophyll content, and N, P, and K tissue content. The results from the field conditions showed that there was a highly significant yield after the treatment with AMF + 50% NPK. The study also revealed that mycorrhizal fungi inoculation increased the available soil N and P concentrations when it was combined with a 50% NPK dose. This suggests that the inoculation of fields with AM fungi can reduce the chemical fertilizer application by half, while improving soil chemistry. The results suggested that AMF inoculation can be used in integrated soil fertility management strategies.
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    Genetic diversity and population structure among Ugandan shea tree (Vitellaria paradoxa subsp. nilotica) accessions based on DarTSeq markers
    (Crop Science, 2023-06-11) Juventine Boaz Odoi; Emmanuel Amponsah Adjei; Prasad Hendre; Judith Ssali Nantongo; Alfred Adibo Ozimati; Arfang Badji; Grace Nakabonge; Richard Edema; Thomas Lapaka Odong
    Molecular markers such as single nucleotide polymorphisms (SNPs) and SilicoDArT are important in dissecting the genetic diversity of a population at DNA level. The two marker types were analyzed using the same genotyping platform. Although the two marker types were analyzed using the same genotyping platform, they were filtered using a different marker stringency. We determined the genetic diversity of 623 half-sibs of shea tree (Vitellaria paradoxa a C. F. Gaertn. nilotica) assembled from five geographical locations (Katakwi, Otuke, Amuru, Moyo, and Arua) in Uganda’s shea parklands. A total of 27,063 Diversity Arrays Technology (DArT) SNP and 9018 SilicoDArT markers were used to assess genetic diversity and population structure. The populations showed a low genetic diversity (Gst = 0.21), very low population differentiation (FST = 0.02), low-to-moderate linkage disequilibrium (r = 0.2), and Hardy–Weinberg Equilibrium (HWE = 0.1982). The study further revealed a higher genetic diversity within population (0.26) than among the population (0.21). A high level of heterozygosity was observed within individuals (0.26) and markers (0.32) revealing a high non-random association of alleles at different loci that offer opportunities to design association studies and allele transfer in marker-assisted selection in the population. The markers varied in their polymorphic information content values (SilicoDArT = 0.11) and (SNPs = 0.15) on genetic diversity. This study reveals the importance of genetic diversity and population structure analysis using high-density DArT-Seq SilicoDaRT and SNP makers in the conservation and breeding of shea tree in Uganda.