Browsing by Author "Ndunguru, Joseph"

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AMMI and GGE biplot analysis of maize genotypes for seed yield across different maize growing location in Tanzania
(Cogent, 2024-12-18) Mwendo, Marco; Mbega, Ernest; Ndunguru, Joseph; Philipo, Mashamba
Twenty maize genotypes including breeding lines along with improved local released varieties were assessed for grain yield and yield component stability under three different maize growing agro-ecological zones from January to August 2023. A randomized complete block design (RCBD) with three replication was employed. additive main effects and multiplicative interaction (AMMI) and genotype-by-environment interaction (GGE) analysis was utilized to study the genotype and environment (GE) interactions. The combined analysis of variance showed a significant difference (p ≤ 0.001) in grain yield traits between maize genotypes, environments, interactions and IPC components. The average mean grain yield ranged from 3244 to 5103 kg/ha with a grand mean of 4111 kg/ha The maximum and minimum grain yield was 12325.93 kg/ha (G4) and 1159.68 kg/ha (G9) respectively. The biplot results showed genotype G20, G3, G1, G17 and G15 demonstrated consistently high stable grain yield performance. Genotypes G14, G19 and G4 had high yields, but were unstable as they were far from the IPC1 zero line. Multi-trait stability value indicated that the best genotypes in performance for all traits were G5, G17 and G19. AMMI analysis revealed that the environment at Kibaigwa and NM-AIST was the most ideal environment for seed yield traits. Based on the consistently high and stable grain yield performance, along with other superior grain qualities and plant characteristics, genotypes G5 and G17 were selected and recommended to be advanced and released as new commercial maize varieties in Tanzania for wider cultivation by farmers together with G19, a commercially released variety in Tanzania.
Characterization of phenotypic traits associated with anthracnose resistance in selected common bean (Phaseolus vulgaris L.) breeding material
(Elsevier Ltd, 2024-02-27) Kadege, Edith; Venkataramana, Pavithravani; Assefa, Teshale; Ndunguru, Joseph; Rubyogo, Jean Claude; Mbega, Ernest
Anthracnose caused by Colletotrichum lindemuthianum is the major common bean disease worldwide causing complete yield loss under favourable disease conditions. This study aimed to determine phenotypic traits associated with anthracnose resistance for future use in breeding programmes. Twenty-two common bean varieties (CBVs) were selected basing on susceptibility to anthracnose, advanced breeding lines, improved variety resembling advanced breeding lines and the farmer variety widely grown in Tanzania. Selected varieties were planted in anthracnose hotspot fields and the same CBVs were planted in a screen house to validate resistance to anthracnose. Anthracnose infection score, leaf length, leaf width, length of fifth internode, length of petiole, plant vigour, canopy height and canopy width were recorded. Data on number of plants emerging; days to flowering; days to maturity; plant stands at harvest; and grain yield were also collected and analysed using R software. Phenotypic traits evaluated differed significantly among genotypes, environment and genotype by environment interaction. Seventy-five percent of phenotypic traits evaluated were positively correlated to anthracnose resistance. Highly-strong correlations to anthracnose were observed on number of days to maturity, plant stands at harvest, plant vigour and grain yield. Leaf length, leaf width, length of fifth internode, length of petiole and number of stands emerging were strongly correlated to anthracnose resistance. Additive main effects and multiplicative interaction analysis (AMMI) revealed highest contribution of environment on anthracnose infection-58.9% and grain yield −84.9% compared to genotype effects on anthracnose infection −32.7% and grain yield-15.7%. Based on these results, four traits – plant vigour, number of days to maturity, number of plant stands at harvest and grain yield – are recommended for selecting anthracnose-resistant varieties. NUA 48, NUA 64 and RWR 2154 were superior varieties, resistant to anthracnose and high yielding, while Sweet Violet and VTT 923-23-10 were most stable varieties across environments. Further on-farm research is suggested to assess their performance and identify traits preferred by farmers.
Comparative Analysis of Phytocompound Variations in Leaves, Bark and Roots of Allspice (Pimenta Dioica) Collections in Tanzania
(AIJR, 2024-02-06) Lutege, Raymond; Venkataramana, Pavithravani; Ndunguru, Joseph
he efficient valorization of biomass for energy-derived biocrudes is essential for effective waste management. However, the production of biocrudes with high energy and reduced oxygen contents during the liquefaction process requires further insight. Therefore, the impact of reaction temperature, residence time, and ethanol: acetone on the energy compositions and bioproduct’s yield enhancement were investigated. The biocrudes obtained were characterized using elemental analysis, GC–MS, FTIR, GPC and TGA to understand the effects of process parameters on the biocrudes’ compositions. An improved HHV (38.18 MJ/kg) and lower O/C ratio (0.11) were obtained at 430 °C, 35 min and 50% ethanol with a significant improvement in the enhancement factor, deoxygenation, and percentage hydrogenation of 2.63, 36.88%, and 77.87%, respectively. The presence of ketones, hydrocarbons, phenolics and aromatics of 23.74, 4.28, 37.20 and 17.81% respectively indicate the potential of the obtained biocrude as renewable energy sources upon further upgrading.
Elevated viral small RNA profiling in cassava cultivars suppress the occurrence of Cassava brown streak disease (CBSD)
(Elsevier, 2024-03) Ngazi, Veneranda; Nyangoko, Baraka; Mukasa, Settumba; Ndunguru, Joseph; Tairo, Fred
Cassava brown streak disease (CBSD), caused by cassava brown streak virus (CBSV) and; Ugandan cassava brown streak virus (UCBSV) causes the most destructive cassava disease in Tanzania. Thus, breeders urgently need CBSD-resistant cultivars to combat the impact of this disease, safeguard cassava production, improve the yields and secure food supply for communities reliant on this staple crop. In this study, we used four cassava cultivars; Albert, KBH 2002/135, KBH 2006/026 and Kiroba to explore how viral small interfering RNA (vsiRNAs), an antiviral silencing mechanism, confers CBSD resistance. Cassava plants were inoculated by grafting method using the single infection of CBSV, UCBSV and mixed infection of these viruses (co-infection). Total RNA was extracted from leaves of each cultivar followed by deep sequencing. The result showed that high level of vsiRNAs was produced in inoculated plants, with the most prominent class being 21 and 22 nucleotides. Kiroba produced the highest level of vsiRNA in both CBSV and UCBSV, whereas KBH 2006/026 produced high level of vsiRNA only with UCBSV infections. In contrast to UCBSV, inoculation with CBSV stimulated severe symptoms but relatively low levels of vsiRNA. Co-infection treatment showed a more complex interaction between the host and virus, with variations in the severity and amount of vsiRNA produced. We conclude that resistance to CBSD varies depending on the type of cultivar and virus species, and the occurrence of CBSD is suppressed in plants with elevated vsiRNA. Therefore, a good understanding on the resistance status of parental materials for breeding is recommended to breeders as a basis for improving cassava production.
Pathogenicity and Approaches for Management of Anthracnose in Common Bean (Phaseolus vulgaris) in Africa
(INTERNATIONAL JOURNAL OF AGRICULTURE & BIOLOGY, 2022-10-16) Kadege, Edith; Venkataramana, Pavithravani; Assefa, Teshale; Ndunguru, Joseph; Mukankusi, Clare; Rubyogo, Jean; Mbega, Ernest
Common bean plays significant role for human health globally and consumption of common bean is high in Africa as compared to other regions of the world. Despite common bean’s potential in Africa, productivity remains low due to diseases, drought and poor crop management. Anthracnose disease plays major role in reducing common bean grain yield in Africa. It is caused by seed-borne fungal pathogen Colletotrichum lindemuthianum leading to 100% yield loss. Limited and fragmented information on fungal infection, pathogenicity and management of common bean anthracnose in Africa affects decisions regarding anthracnose management. This review has been produced to collect information regarding anthracnose disease and its management in beans in Africa, which will be of great value to bean stakeholders. C. lindemuthianum can survive up to five years in infected seeds. During this time, seed is the main source of inoculum, infection and transmission of pathogen to new locations. Other sources and mechanisms of transmission include infected residues, farm tools, water, wind, and disturbance of moist foliage by animals, insects and people. Anthracnose is a hemibiotrophic pathogen, first establishing biotrophic interactions with common bean plant before switching to necrotrophism, causing significant yield loss. Mechanical force, chemical weapons, toxins and growth regulators facilitate pathogenesis. Use of anthracnose-resistant varieties is recommended to control common bean anthracnose followed by integrated anthracnose management. Future research in Africa should focus on why farmers rely heavily on local bean cultivars as seed and should use tricot as tool to screen anthracnose-resistant varieties and evaluate anthracnose management options for increased productivity, nutrition and income.
Phylogenetic Diversity of Allspice (Pimenta Dioica) Collections from Tanzania Using Chloroplast (Cp) Rbcl Gene
(Heliyon, 2023) Lutege, Raymond; Venkataramana, Pavithravani; Ndunguru, Joseph; Boykin, Laura
This study aims to investigates the phylogenetic relationship between various collection of Allspice (Pimenta dioica) from Tanzania using cprbcL gene as a DNA barcode. Allspice is an important plant species valued for its economic, medicinal, and cultural uses. The morphological similarities between Allspice and other trees in the Myrtaceae family have led to misidentification, making it crucial to use DNA barcoding to study their evolution history. The molecular phylogeny was conducted using DNA extraction, PCR amplification, and sequencing of the rbcL gene, followed by phylogenetic analysis. The genomic DNA was extract using the CTAB method and the rbcL gene amplified with a forward primer 5’-ATGTCACCACAAACAGAGACTAAAGC-3’ and a reverse primer 5’-GTAAAATCAAGTCCACCRCG-3’. Phylogenetic analysis of Allspice rbcL gene was performed by multiple sequence alignment using MUSCLE 5.1 embedded in Geneious Prime software version 2023.0.1 phylogenetic tree was constructed using the same software. The results showed that DNA specimen amplified at amplicon size of average 560bp with GC content of 44%. BLASTN search resulted into more than 96% similarity to seventeen members of Myrtaceae family namely Eucalyptus torquata (NC_022401), Eucalyptus spathulata (NC_022400), Eucalyptus torquata (KC180794), Eucalyptus spathulata (KC180793), Syzygium polyanthum (OQ355361), Syzygium aromaticum (ON920513), Luma apiculata (KX162972), Eugenia aggregata (OP650216), Eugenia Selloi (MN095411), Myrcianthes pungens (MN095409), Campomanesia xanthocarpa (KY392760), Acca sellowiana (KX289887), Syzygium samarangense (NC_060657), Lophomyrtus bullata (MW214669), Lenwebbia prominens (MW214668), Lenwebbia lasioclade (MW214667), and Syzygium nervosum (NC_053907). In the phylogenetic tree Allspice rbcL gene has a close branch to members of Myrtaceae family. This study concludes that there is high genetic diversity among Allspice collection from Tanzania and between member of the Myrtaceae family. Additionally, this study provides a foundation for future research on the evolutionary history and population genetics of Allspice in Tanzania.