Browsing by Author "Chilagane, Luseko Amos"

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Characterization of the common bean host and Pseudocercospora griseola, the causative agent of angular leaf spot disease in Tanzania
(African Journal of Plant Science, 2016) Chilagane, Luseko Amos; Msolla, Susan Nchimbi; Kusolwa, Paul Mbogo; Porch, Timothy Gabriel; Diaz, Luz Miryam Serrato; Tryphone, George Muhamba
Angular leafspot (ALS), caused by the fungus, Pseudocercospora griseola, is one of the most important disease of common bean in Tanzania. Breeding for resistance to this disease is complicated by the variable nature of the pathogen. In Tanzania, a thorough analysis of the variability of this pathogen is lacking which limits breeding for durable resistance. This work aimed at characterizing P. griseola in relation to its host in Tanzania. A sample collection of both P. griseola and common bean was conducted in the 2013 and 2014 growing seasons from nine regions. Single spore isolation was performed for P. griseola isolates and DNA was extracted from both P. griseola mycelium and bean leaves from which the pathogen was collected. For characterization of the gene pool origin of the host, Phaseolin DNA marker was evaluated and for the pathogen, the Internal Transcribed Spacer region (ITS) and the Actin gene sequences were evaluated. Phylogenetic analysis showed the presence of 69.7% Andean and 30.3% Mesoamerican strains of P. griseola in Tanzania. The common bean host genotypes showed a similar distribution with 84.2% Andean and 15.8% Mesoamerican. In both cases, Andean strains of the pathogen and Andean bean genotypes outnumbered Mesoamerican. In relation to the common bean genotypes, Andean genotypes were more susceptible to ALS as compared to Mesoamerican genotypes. There were few strains that were of Andean origin but were pathogenic on Mesoamerican common bean genotypes, a group that has previously been termed Afro-Andean. Geographically, most of the regions of Tanzania had only Andean strains except for Kagera where 60% were Mesoamerican strains, and in Arusha and Tanga, where 50 and 33% were Mesoamerican, respectively. Only three regions, Kagera, Mbeya and Rukwa, were found to grow Mesoamerican beans. The findings of this study are important in setting basic objectives for breeding for angular leaf spot disease in Tanzania.
Genetic characterization of angular leaf spot resistance in selected common bean landraces from Tanzania
(African Journal of Biotechnology, 2015-10-28) Tryphone, George Muhamba; Chilagane, Luseko Amos; Nchimbi-Msolla, Susan; Kusolwa, Paul Mbogo
Angular leaf spot disease (ALS) caused by Pseudocercospora griseola is one of the most important bean diseases in Tanzania. The bean landraces Beti-10, Nanka, Nanavala and Nkanamna used in this study have been identified as resistant to ALS but the nature of inheritance and mechanisms of resistance against ALS in those potential sources has not been elucidated. This information is crucial and a necessary first step for a successful breeding programme. The objective of this work was to study the inheritance of ALS resistance in those landraces and to identify the mechanisms of genetic resistance using Simple Sequence Repeat (SSR) markers. Crosses were made between resistant bean landraces and a susceptible bean cv Kablanketi. The parents, F1, F2 and backcrosses derived plants were used for inheritance studies and for molecular marker screening using 30 SSR markers. Results indicate that, a single dominant gene control resistance against ALS in each of the four landraces; also the SSR marker Pv-ag004 was found to be polymorphic between Beti-10 and Kablanketi and linked to the disease resistance. The resistance were validated by checking the F2 population of the cross between Kablanketi × Beti-10. Therefore, since marker Pv-ag004 is polymorphic and linked to ALS resistance, the Beti-10 landrace might be a potential source of ALS resistance. However, a detailed study with more markers need to be done on these landraces with a view to opening the possibilities of identifying new markers linked to ALS resistance and mapping of genes associated with resistance to ALS.
Inheritance of Angular Leaf Spot [Phaeoisariopsis griseola (Sacc.) Ferr] Resistance in Common Bean (Phaseolus vulgaris L.) Population Developed from Kablanketi Mexico 54
(Journal of Agricultural Science and Technology, 2012-07-20) Tryphone, George Muhamba; Chilagane, Luseko Amos; Kusolwa, Paul Mbogo; Nchimbi-Msolla, Susan
The genetic resistance to angular leaf spot (ALS) caused by Phaeoisariopsis griseola in the common bean cultivar Mexico 54 was investigated on disease reactions in parental, F1, F2 and backcross generations derived from crosses between a resistant cultivar Mexico 54 and a susceptible cultivar Kablanketi under screen house conditions. The heritability (h2) estimate was as high as 0.719 indicating a successful transfer of ALS resistance among progenies and thus selection can be performed in early generation. High heritability coupled with high expected genetic advance of 39.5% is considered to be more useful in predicting the outcome of selecting the best individuals. Chi-square values were computed to determine whether the observed ratios for disease reactions deviated from expected Mendelian ratios for a single, dominant gene controlling resistance to angular leaf spot in common bean. Based on the resistance of the F2, and the backcross generation to the resistant parent, a 3 resistant: 1 susceptible segregation ratio in the F2 and a 1 resistant: 1 susceptible segregation ratio in the backcross generation to the susceptible parent was obtained implying that resistance to the isolate of Phaeoisariopsis griseola is governed by a single, dominant gene.
Inheritance of angular leaf spot [Phaeoisariopsis griseola (Sacc.) Ferr] resistance in common bean (Phaseolus vulgaris L.) population developed from Kablanketi x Mexico 54
(David Publishing, 2012-07-20) Nchimbi-Msolla, Susan; Tryphone, George Muhamba; Chilagane, Luseko Amos; Kusolwa, Paul Mbogo
The genetic resistance to angular leaf spot (ALS) caused by Phaeoisariopsis griseola in the common bean cultivar Mexico 54 was investigated on disease reactions in parental, F1, F2 and backcross generations derived from crosses between a resistant cultivar Mexico 54 and a susceptible cultivar Kablanketi under screen house conditions. The heritability (h2 ) estimate was as high as 0.719 indicating a successful transfer of ALS resistance among progenies and thus selection can be performed in early generation. High heritability coupled with high expected genetic advance of 39.5% is considered to be more useful in predicting the outcome of selecting the best individuals. Chi-square values were computed to determine whether the observed ratios for disease reactions deviated from expected Mendelian ratios for a single, dominant gene controlling resistance to angular leaf spot in common bean. Based on the resistance of the F2, and the backcross generation to the resistant parent, a 3 resistant: 1 susceptible segregation ratio in the F2 and a 1 resistant: 1 susceptible segregation ratio in the backcross generation to the susceptible parent was obtained implying that resistance to the isolate of Phaeoisariopsis griseola is governed by a single, dominant gene.
Races of Colletotrichum lindemuthianum (Sacc. & Magnus) Briosi & Cavara in major bean growing regions in Tanzania
(Academic Journals, 2020-06) Mpeguzi, Masunga; Susan, Nchimbi-Msolla; Mabagala, Robert; Chilagane, Luseko Amos
Breeding for resistant varieties has been shown to be the most suitable method to control bean anthracnose caused by Colletotrichum lindemuthianum though the method is challenged by the existence of many races of the pathogen. This work focused on characterizing races of C. lindemuthianum from potential bean agro ecological zones of Tanzania using a set of differential bean cultivars. From 144 anthracnose infected bean samples collected, 50 pure isolates were obtained and characterized whereby 42 races were identified. The most virulent race identified was race 3610 from the Southern Highland zone of Tanzania while the least virulent was characterized as race 0. Race 2 was the most widely spread (4.2 %) found in Northern, Southern highland and in Eastern zones of Tanzania. The work confirms that G2333 can still be used as a potential donor of resistant genes to varieties that are to be grown in Northern, Eastern and Lake zones but not for the varieties from Southern Highland 2 and Western zones of Tanzania since isolates from these zones overcame resistant genes Co-4 , Co-5, Co-7 in G2333. 95% of all races which were identified are new and were not specific to either Mesoamerican or Andean origin common bean.
Yield Advantage of Elite Cereal and Legume Genotypes in Varying Potential Agro-ecologies of Central Tanzania
(2021) Wabwire, Simon; Chilagane, Luseko Amos; Msuya, Dunstan Gabriel
Ten elite genotypes in total (of groundnut, pigeon pea, sorghum and pearl millet) and four local checks (one for each crop) were used in the study to identify legume and cereal genotypes of higher productivity in the varying potential agro-ecologies. The experiments were established following an incomplete randomized block design with two farmers selected per sub agro-ecology as replications. Combined analysis of variance over locations was carried out for grain yield and yield components. The results showed significant differences (P ≤ 0.05) among groundnut and pearl millet genotypes tested for grain yield while for pigeon pea and sorghum genotypes the differences were insignificant (P ≤ 0.05). Genotype ICGV-SM 05650 of groundnut had the highest grain yield of 2105.08 kg ha-1, whereas the lowest grain yield of 1538.87 kg ha-1 was recorded in ICGV-SM 02724 in the high potential agro-ecology. Pearl millet genotype IP 8774 ranked highest in terms of yield performance (1049.4 kg ha-1) and the local check had the lowest yield of 388.9 kg ha-1. Though non significant differences (P ≤ 0.05) among genotypes tested for grain yield were observed in pigeon pea and sorghum genotypes however, pigeon pea genotype ICEAP 00040 had a slightly higher grain yield of 779.17 kg ha-1 and sorghum genotype GAMBELLA 1107 outperformed the other genotypes with grain yield of 1420.8 kg ha-1. Genotypes ICGV SM 05650, ICEAP 00040, GAMBELLA 1107 and IP8774 were therefore recommended for deployment in these varying potential agro-ecologies due to their superior performance in terms of grain yield.