Browsing by Author "Clare Mukankusi"

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Genetic clustering, and diversity of African panel of released common bean genotypes and breeding lines
(Springer Nature, 2023-03-08) Winnyfred Amongi; Stanley Tamusange Nkalubo; Mildred Ochwo‐Ssemakula; Arfang Badji; Isaac Onziga Dramadri; Thomas Lapaka Odongo; Ephraim Nuwamanya; Phineas Tukamuhabwe; Paulo Izquierdo; Karen Cichy; James Kelly; Clare Mukankusi
Common bean is a grain legume of global importance especially for proteins and micronutrients. The crop is a staple food in sub-Saharan Africa, where it has gained importance in iron bioforti cation for people prone to anemia. However, biotic and abiotic constraints, long cooking time, and high phytic acid and polyphenols both of which affect bioavailable iron, hinder the production and health benefits. To inform breeding decisions, the study determined genetic diversity and population structure within 725 breeding lines, varieties, or landraces mostly from Uganda and South America. Genotyping by sequencing and diversity array technology (DarTseq) were used to generate single nucleotide polymorphic markers on Set1 (427) and Set2 (298) germplasm, respectively. The germplasm were grouped into Andean and Mesoamerican gene pools, with the latter as the larger subpopulation. Analysis of molecular variance revealed 46% (Set1) and 50% (Set2) of genetic variation among the subpopulations, with fixation indices (FST) of 0.54 (Set1) and 0.71 (Set2) among Andean and Mesoamerican beans, respectively. The overall germplasm’s gene diversities were 0.206 (Set1) and 0.332 (Set2). Admixtures were the most diverse (0.193) in both sets of germplasm. The germplasm exhibited high genetic diversity and as a result they have a high potential for use in plant breeding. Inter- gene pool crosses within and across market classes are possible and considering both approaches is expected to increase diversity to realize genetic gain. The structure and polymorphic information generated provided useful perspectives for genomic breed- ing and genome-wide association study using the population.
Inheritance of resistance to common bacterial blight in four selected common bean (Phaseolus vulgaris L.) genotypes
(2017-06-09) Boris M. E. Alladassi; Stanley T. Nkalubo; Clare Mukankusi; Eric S.Mwale; Paul Gibson; Richard Edema; Carlos A. Urrea; James D. Kelly; Patrick R. Rubaihayo
Common bacterial blight (CBB) is the most serious bacterial disease of common bean in Uganda. It causes severe yield losses of up to 62%. Genetic resistance is the most effective option for controlling CBB in smallholder common bean production systems. This study was carried out to determine the inheritance pattern of CBB resistance in leaf and pod of four new resistance sources. The four resistant and four susceptible genotypes were crossed in a half-diallel mating design. F1 individuals were advanced to F2 and evaluated with the parents, in a randomized complete block design replicated twice. Combining ability analysis was performed according to Griffing's (1956) method IV and model 1 using Genstat 12th. General combining ability effects were significant whereas specific combining ability was not suggesting that resistance to CBB in leaf and pod was primarily controlled by additive genes effects. The estimated narrow sense coefficient of genetic determination was moderately high (0.65) for the resistance in leaf and high (0.83) for resistance in pod suggesting that early-generation selection would be effective. Baker’s ratio estimates were relatively high for resistance in leaf (0.79) and pod (0.9) suggesting that hybrids’ performance can be predicted based on the parents’ general combining ability (GCA) effects.
Prevalence and variability of the common bean rust in Uganda
(Afr. J. Agric. Res., 2017-01-06) Blessing Adanta Odogwu; Stanley Tamusange Nkalubo; Clare Mukankusi; Pamela Paparu; Rubaihayo Patrick; James Kelly; Steadman James
Uganda is the second largest producer of dry beans (Phaseolus vulgaris L.) in Africa, but common bean rust caused by Uromyces appendiculatus (Pers. Unger), is negatively impacting the production of the crop. There is little information on the occurrence and identity of the rust pathotypes present in the country. Consequently, a field survey was carried out during the 2015 second planting season in fifteen districts, representing the areas of high beans production in Uganda. High common bean rust incidence and severity were observed in the low altitudes and the South-Western Highlands of Uganda. Wakiso and Hoima districts had the highest rust disease incidence 72 and 76% respectively and severity rates of 6 and 5.5, respectively. Rust disease incidence was uniformly high on commercial genotypes and landraces. Similarly, high rust disease incidence and severity were observed in the bean-maize– groundnut cropping system. Twenty-three single rust isolates were collected in Uganda and inoculated on 11 bean rust differentials and Ouro Negro (Ur-14) genotypes. Six rust pathotypes were identified and these included 2-0, 4-0, 50-0, 5-1, 4-33 and 63-19. Five of the pathotypes were of Andean origin and only pathotype 4-33 was of Mesoamerican origin. The rust pathotype 63-19 showed similar pathogenic characteristics with the Puerto Rico rust race 19-63. This study provides critical baseline information to integrate breeding and crop protection in the efforts to develop an overall strategy for the management of common beans in Uganda.