Browsing by Author "Rubaihayo Patrick"

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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.
Variety × Environment × Management Interaction of Diseases and Yield in Selected Common Bean Varieties
(Agronomy Journal, 2017-04-07) Awio Bruno; Mukankusi M. Clare; Nkalubo T. Stanley; Gibson Paul; Malinga G. Maxwell; Rubaihayo Patrick; Edema Richard
Understanding variety × environment interaction (VEI) and variety × management interaction (VMI) are critical for deploying superior crop varieties to responsive environments. We evaluated 15 common bean (Phaseolus vulgaris L.) varieties in a split-plot design under two fertilizer regimes, for two sea- sons, and in six locations in Rakai and Hoima districts, Uganda. We assessed VEI and VMI effects on plant vigor, plant height, number of pods per plant, grain yield, and reaction to angular leaf spot (ALS) (Psuedocercospra griseola), common bean rust (CBR), common bacterial blight (CBB) (Xanthomonas campestris pv. phaseoli), and anthracnose on pods (ANTP) (Colletotrichum linemuthianum) under eld conditions. e seasons and fertilizer levels were considered as separate environments resulting in 24 environments. Variety × location × season interaction had a significant effect on the reaction to ALS, CBR, and grain yield. e VEI and VMI analysis grouped the 12 environments into two mega-environments based on grain yield in different seasons and fertilizer levels. ROBA1, Masindi Yellow Long, and NABE2 varieties had the highest grain yield in the different mega-environments. e Farmers’ variety and varieties KATX69 and KATX56 were stable, whereas NABE2, RWR719, and ROBA1 were unstable in grain yield performance. Genotypic correlations between traits were stronger in Hoima than in Rakai. e diseases correlated negatively with grain yield, and were strong in the second season of Hoima district. The Katumani varieties and landraces were susceptible to disease in the environments. us, increased production of landraces, KATX69 and KATX56 could be attained by improving their disease resistance.