Browsing by Author "Judith Ssali Nantongo"

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End-user preferences to enhance prospects for varietal acceptance and adoption in potato breeding in Uganda
(Journal of The Science of Food and Agriculture, 2023-09-15) Judith Ssali Nantongo; Samuel Edgar Tinyiro; Mariam Nakitto; Edwin Serunkuma; Prossy Namugga; Oluwatoyin Ayetigbo; Sarah Mayanja; Mukani Moyo; Reuben Ssali; Thiago Mendes
BACKGROUND: Potato varieties have diverse biophysical characteristics, so it is important for breeders to have the capacity to choose those that meet the preferences of end users, such as mealiness, firmness, and taste, among others. Combining user preferences with descriptive information regarding the sensory characteristics of boiled potatoes can contribute to the improvement of consumer-driven varieties. This study aimed to factor in the preferences of end users to improve the prospects for varietal acceptance, adoption, and discrimination among genotypes in potato breeding. RESULTS: The priority quality traits (traits that play the most significant roles in acceptance and adoption) of the boiled potatoes were determined by evaluating gender and livelihood using the G+ tool. The G+ tool is designed to assess gender impact on roots, tubers and bananas (RTB) traits by serving as a validation check to reflect on important gender-based issues in agri- cultural food systems in order to reduce harm and promote positive impact. Potato genotypes were differentiated by penetration (textural parameters as measured by standard texture probe) and the procedure was repeatable, as there was no significant difference between the cooking replicates at 40 min of cooking. Instrument-based texture parameters, such as penetration peak force (hardness/firmness) and area (area under the curve, which represents energy needed to penetrate) of boiled potato tubers were significantly associated with sensory attributes such as fracturability and hardness in the mouth. An attempt to differentiate genotypes using near-infrared spectroscopy (NIRS) revealed that the average results observed for the calibration for yellow color (r2 = 0.70), homogeneity of color (r2 = 0.48), moisture in mass (r2 = 0.40), and uniformity of texture (r2 = 0.56) suggested that these parameters could be used for initial breeding screening purposes. CONCLUSIONS: The preferred traits of the boiled potato can be integrated into the potato-breeding program/product profile. Near-infrared spectroscopy shows strong potential to predict potato color and the ability of NIRS models to predict some texture attributes is also promising. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
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.
Insect pests in apple (Malus domestca Borkh) gardens: Review
(GSC Advanced Research and Reviews, 2023-07-09) Emilly Kamusiime; Judith Ssali Nantongo; Cosmas Wacal
Apple (Malus domestica), is one of the most important fruit trees cultivated in temperate regions but, newly introduced in Uganda for its income and nutritional importance. However, apples are found to be susceptible to arthropod pests, some known to cause damages on both the plant and fruits. Some of these insect pests are known while others are still unknown and could be effectively managed through integrated pest management methods. For any effective Integrated insect Pest Management, it is necessary to have enough information about the biology and ecology of a given pest, including, spatial distribution and factors that affect pest species’ distribution. Therefore, in this paper, systematic information on insect pests damaging apple fruit trees was reviewed. Different recent literature on insect pests hosted by apples under different agroecological systems of the world was reviewed. The review focused on classifying common insect pests, preferred varieties and their ecological distribution. This was achieved by using the ISI Web of Science bibliographic database and search terms such as apple entomofauna and insect pests were used, with specific keywords of [apple*] AND [insect*] AND [pest]. It was found out that, insect pests in apples belong to several groups of invasive pests which include Coleoptera and Polydrusus (beetles, weevils), Diptera (leaf, seed, fruit flies), Hemiptera (aphids, psyllids, bugs and scales), Hymenoptera (sawflies, wasps ants, bees), Thysanoptera (thrips), Trombidiformes (mites) and Lepidoptera (moths and butterflies) that are of economic value. This work, again reveals dramatic rates of appearance of insect pests in orchards in Africa and elsewhere, which have compromised apple industry’s growth. The review pieced together known information about the insect pests that occurs in apples in different geographical locations. But, information on insect pest in Uganda’s apple orchards remained scanty, which calls for an immediate detailed study on the same.
SilicoDArT and SNP markers for genetic diversity and population structure analysis of Trema orientalis; a fodder species
(PLOS One, 2022-08-22) Judith Ssali Nantongo; Juventine Boaz Odoi; Hillary Agaba; Samson Gwali
Establishing the genetic diversity and population structure of a species can guide the selection of appropriate conservation and sustainable utilization strategies. Next-generation sequencing (NGS) approaches are increasingly being used to generate multi-locus data for genetic structure determination. This study presents the genetic structure of a fodder species -Trema orientalis based on two genome-wide high-throughput diversity array technology (DArT) markers; silicoDArT and single nucleotide polymorphisms (SNPs). Genotyping of 119 individuals generated 40,650 silicoDArT and 4767 SNP markers. Both marker types had a high average scoring reproducibility (>99%). Genetic relationships explored by principal coordinates analysis (PCoA) showed that the first principal coordinate axis explained most of the variation in both the SilicoDArT (34.2%) and SNP (89.6%) marker data. The average polymorphic information content did not highly differ between silicoDArT (0.22) and SNPs (0.17) suggesting minimal differences in informativeness in the two groups of markers. The, mean observed (Ho) and expected (He) heterozygosity were low and differed between the silicoDArT and SNPs respectively, estimated at Ho = 0.08 and He = 0.05 for silicoDArT and Ho = 0.23 and He = 0.19 for SNPs. The population of T. orientalis was moder- ately differentiated (FST = 0.20–0.53) and formed 2 distinct clusters based on maximum likelihood and principal coordinates analysis. Analysis of molecular variance revealed that clusters contributed more to the variation (46.3–60.8%) than individuals (32.9–31.2%). Overall, the results suggest a high relatedness of the individuals sampled and a threatened genetic potential of T. orientalis in the wild. Therefore, genetic management activities such as ex-situ germplasm management are required for the sustainability of the species. Ex-situ conservation efforts should involve core collection of individuals from different populations to capture efficient diversity. This study demonstrates the importance of silicoDArT and SNP makers in population structure and genetic diversity analysis of Trema orientalis, useful for future genome wide studies in the species.