Browsing by Author "Mukankusi, C."
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Item Development of White Common Beans for the Processing Industry in East Africa: Adaptability, Resistance to Selected Diseases, Cooking Time and Canning Quality(Africa Crop Science Journal, 2021) Amongi, W.; Kato, F.; Male, A.; Musoke, S.; Acam, C.; Kabwama, A.; Nakyanzi, B.; Sebuliba, S.; Williams, M.; Mbiu, J.; Baguma, G.; Mukankusi, C.Common bean (Phaseolus vulgaris L.) provides dietary protein, energy, fiber, and micronutrients, especially iron and zinc to over 800 million people in Africa and Latin America. The crop has various seed types. White beans are very popular for the processing industry. This study aimed to investigate the agronomic performance, canning quality, cooking time (COOKT) and response to root rots (Fusarium cuneirostrum and Pythium ultimum) and angular leaf spot (ALS; Pseudocercospora griseola) diseases among 151 drought tolerant small and large seeded white bean genotypes from trials conducted between 2013 to 2018 in East Africa. Significant (P<0.001) differences existed among the genotypes for response to the three pathogens, COOKT and canning quality traits. Resistance to each of the pathogens was expressed in 24-75% of the genotypes, while dual resistance to any two pairs of the pathogens occurred in 10-44% of the genotypes. Four genotypes; ICNBunsixSxB405/4C- 1C-1C-88, RAZ-11, ETSNAP18 and ETSNAP3 expressed resistance to the three pathogens but had COOKT of 46-56 minutes (based on a Matson cooker), and below average canning quality. They are recommended as sources of diseases resistance but could be further improved for COOKT and canning quality. Sixty-eight genotypes had COOKT <50 minutes while 24 expressed good to excellent visual canning quality. Some phenotypes: RAZ-120, RAZ36-Caballero, NavyLine-60, NavyLine-25, ZABR16573-25F22, ZABR16575-60F22, ETSNAP33, Bifortsmallseeded-15 and ZABR16574-37F22, that were cooked in <45 minutes, exhibited good to excellent canning quality and expressed resistant to intermediate diseases resistance responsesItem Distribution and Variability of Pseudocercospora griseola in Uganda(Journal of Agricultural Science, 2012) Ddamulira, G.; Mukankusi, C.; Ochwo-Ssemakula, M.; Edema, R.; Sseruwagi, P.; Gepts, P.is highly variable with many different races occurring in different agro-ecological zones. Therefore, for an effective breeding program, there is a need to continuously monitor the distribution and variability of the pathogen as a means of guiding breeders on which races to target. A study was conducted to assess the incidence, severity and variability of P. griseola in bean growing districts of Dokolo, Lira, Apac, Sironko, Mbale, Rakai, Lwengo, Bukomansibi, Kabale and Kisoro in Uganda. Forty five out of 80 isolates collected were tested on a set of 12 international bean differentials cultivars for ALS. Molecular markers were also used to elucidate the variability among isolates. In all districts, ALS was found wide spread with a mean incidence of 49.9%. Dokolo district had the highest disease incidence and severity, while Kisoro registered the lowest values respectively. In terms of altitude, incidence (60%) and severity (45%) were high for bean fields located between 1000-1200 m and low disease incidence (33.6%) and severity (20.7%) for fields lying above 1500 m. The standard differential cultivars and molecular markers defined 12 pathotypes and 30 haplotypes respectively. These belonged to Middle America and Andean group with considerably high level of diversity. Our findings indicated the presence of ALS in Uganda with high incidence, severity and variability across districts and altitudes. Hence strategic interventions involving integrated disease management and breeding for durable resistance are required to manage the disease.Item Identification of Common Bean Genotypes with Dual Leaf And Pod Resistance to Common Bacterial Blight Disease in Uganda(Crop Science Journal, 2018) Alladassi, B.M.E.; Nkalubo, S.T.; Mukankusi, C.; Kayaga, H.N.; Gibson, P.; Edema, R.; Urrea, C.A.; Kelly, J.D.; Rubaihayo, P.R.Common Bacterial Blight (CBB), caused by Xanthomonas axonopodis pv. phaseoli (Xap) and Xanthomonas axonopodis pv. phaseoli var. fuscans (Xapf), is a serious disease that affects common bean production worldwide. In Uganda, it is the most severe and widely occurring bacterial disease, causing significant yield losses in common bean. Although various sources of resistance have been developed around the world, none of the varieties grown in Uganda is known to be resistant. The objective of this study was to identify lines with combined leaf and pod resistance for introgression into locally adapted but susceptible Ugandan genotypes. A total of 132 common bean accessions was evaluated in a screenhouse and under field conditions, in an 11x12 alpha lattice design. Genotypes were inoculated with a local isolate in a screenhouse; while the plants were left to undergo natural infestation in field. Results indicated significant differences (P<0.001) in genotypic reactions against the CBB disease, with a range of disease scores of 2.2 - 7.8 on leaves and 2.6 - 7.1 on pods (1-9 CIAT disease scale), suggesting high genetic variability among the tested germplasm. Relatively low correlation (r = 0.39) was observed between leaf and pod reactions, suggesting differential expression of CBB resistance in these two plant organs. Overall, four genotypes, NE2-14-8, NE17-14-29, NE14-09-78 and VAX3, consistently showed resistance in both screenhouse and field evaluations, leaf and pod inoculations and at all sampling stages. These genotypes were, therefore, identified for transferring CBB resistance into Ugandan susceptible market class bean varieties.Item Identification of new sources of resistance to angular leaf spot among Uganda common bean landraces(Canadian Journal of Plant Breeding, 2014) Ddamulira, G.; Mukankusi, C.; Ochwo-Ssemakula, M.; Edema, R.; Sseruwagi, P.; Gepts, P.Breeding for resistance to Angular Leaf spot (ALS), a fungal disease caused by Pseudocercospora griseola (Sacc), is faced with a challenge of the existence of a few resistance sources that are exotic and not well adapted to environmental conditions in Uganda. In addition, P. griseola is a highly variable pathogen that co-evolves with its host, therefore necessitating the continuous identification of new and stronger sources of resistance. Identification of local bean landraces/adapted bean varieties with resistance to ALS would probably quicken the progress of development of resistant cultivars, and reduce yield losses. Seventy four landraces, four commercial varieties, and two controls were screened with four P. griseola pathotypes 1:6, 17:39, 21:39, and 61:63 to determine their ALS resistance levels. One landrace, U00297, showed consistent and strong resistance to the four pathotypes. The inheritance of resistance in U00297 was established from three individual populations derived from crosses with three susceptible cultivars, K132, K131, and Kanyebwa, commercially grown in Uganda. The allelic relationships between U00297 and two existing ALS resistance sources, AND277 and G5686 were tested. Segregation ratios of F2 populations revealed that U00297 resistance to pathotype 17:39 is conferred by a single dominant gene, while digenic epistatic gene interactions were suggested for resistance to other pathotypes. The general and specific combining abilities were significant for resistance revealing the importance of additive and dominant components in the inheritance of ALS resistance. As a resistant parent, U00297 was a good combiner for resistance to pathotype 17:39, and effective resistance source to pathotypes 17:39 and 61:63. The allelic test indicated that the dominant gene in U00297 is independent of resistance genes harboured by resistance sources AND277 and G5686. The information generated is useful to breeding programs targeting developing bean cultivars carrying novel ALS resistance based on genes derived from U00297.Item Improvement of Resistance to Fusarium Root Rot through Gene Pyramiding in Common Bean(African Crop Science Journal, 2012) Obala, J.; Mukankusi, C.; Rubaihayo, P.R.; Gibson, P.; Edema, R.Fusarium root rot (FRR), caused by Fusarium solani f.sp. phaseoli, is one of the most serious root rot diseases of common bean (Phaseolus vulgaris L.) throughout the world. Yield losses of up to 84% have been attributed to the disease. Development and deployment of resistant materials is the most feasible approach to managing the disease. The objective of this study was to estimate the number of pyramided Fusarium root rot resistance genes among the four resistant lines and determine their effectiveness in improving levels of resistance to Fusarium root rot in the susceptible bean cultivars. Crosses among four Fusarium root rot (Fusarium solani f.sp. phaseoli) resistant common bean (Phaseolus vulgaris) were developed. They involved six inbred lines, MLB-48-89A (M48), MLB-49-89A (M49), G2333 (G2) and G685 (G6), and two susceptible cultivars, K20 and Kanyebwa, The resistant lines were used to develop a double cross (DC) population. The DC F1 and each resistant parent were crossed to each of the two susceptible cultivars to form five-parent and single crosses, respectively. Developed populations were subjected to Fusarium solani f. sp. phasoeli isolate-3 under screenhouse conditions. There were segregation ratios of 15:1 (χ2 = 1.89, P = 0.17), 61:3 (χ2 = 0.18, P = 0.67) and 249:7 (χ2 = 1.74, P = 0.19) indicating that two, three and four genes independently condition resistance to F. solani in lines G2 x G6, M49 x M48 and (M49 x M48) x (G2 x G6). A good fit of only four genes in the double cross compared to two in the G2 x G6 , and three genes in the M49 x M48 cross suggests that at least one parent in the G2 x G6 cross have the same or closely linked genes as a parent in the M49 x M48 cross. The F1 means of the five-parent cross (FPC) involving either susceptible parent had lower disease scores, though not significantly (P > 0.05), than the single-crosses from that parent. The F2 of both FPC showed less disease than the single-cross (SC) means (P < 0.05) compared to the single-cross (SC) while the F2 of both FPC had a significant negative deviation (P < 0.05). The F2 frequency distributions also showed that the FPC in both Kanyebwa and K20 populations had higher proportions of resistant plants than any of the single crosses in the respective populations. The superior performance of the FPC over the SC demonstrates that combining resistance genes form different FRR resistance sources can provide a stable source of resistance than using single sources of resistance.Item Potential sources of high iron and zinc content in Ugandan bean germplasm(RUFORUM, 2012) Mukamuhirwa, F.; Tusiime, G.; Mukankusi, C.; Gibson, P.; Edema, R.The study was conducted at National Agricultural Research Laboratories (NARL) at Kawanda in order to identify potential sources of high iron and zinc content, Such varieties would contribute to improved health of bean (Phaseolus vulgaris) consumers, who, despite a high consumption of beans, suffer from anemia caused by micronutrient malnutrition (especially iron and zinc). One hundred and eighty seven genotypes from Uganda were screened for iron (Fe) and zinc (Zn) content. The mineral analysis revealed that there was significant (P=0.001) diversity in Fe and Zn content among the Ugandan genotypes with the range of 45 to 87mg/kg of iron and 22 to 40 mg/kg of zinc. Ten Ugandan bean varieties were identified as potential sources of both high iron and zinc content.Item Prevalence of Angular Leaf Spot Disease and Sources of Resistance in Common Bean in Eastern Democratic Republic Of Congo(African Crop Science Journal, 2017) Kijana, R.; Abang, M.; Edema, R.; Mukankusi, C.; Buruchara, R.Angular leaf spot (Pseudocercospora griseola Crous U, Brown) is one of the most important diseases hindering common bean (Phaseolus vulgaris L.) production in the Great Lakes Region of Africa, including the Democratic Republic of Congo. The disease causes extreme yield losses, estimated at 384.2 tonnes per year, in Sub-Saharan Africa. Little is known about the distribution, severity and incidence of the disease and the effect of agronomic practices and environmental factors on the disease prevalence in the country to facilitate interventions. A field survey was conducted during two crop seasons, February to June and September to January, in two main beans growing zones of eastern DRC namely; sub-humid highland and sub-humid mid altitude at low latitudes, in South and North Kivu, respectively. Severity and incidence of angular leaf-spot and other occurring diseases were assessed on common bean plants in farmers’ fields. Angular leaf spot in these fields had an average severity index (PSI) of 49.9%. PSI was significantly different (P<0.05) between districts and seasons. Using multiple regression analysis, independent variables: growth stage, cropping system, districts and altitude were shown to have significant influence on the observed PSI (P<0.05) with R2 = 96.2%. The highest severity (PSI=59.7%) was observed in Kabare district, and the lowest in Uvira district (PSI=39.5%). Screening of a set of 37 released common bean varieties in DRC using virulent Andean and Mesoamerican isolates identified four resistant bean varieties; ARA 4, COD MLV 059, MLV 224/94B, LSA 144 and Mexico 54. Some of these varieties possess useful traits, in addition to acceptable seed market class, and are hence recommended as suitable parents for ALS resistant variety development and promotion in ALS prone environmentsItem Resistance of Andean beans and advanced breeding lines to root rots in Uganda(African Crop Science Journal, 2020) Amongi, W.; Kato, F.; Male, A.; Musoke, S.; Sebuliba, S.; Nakyanzi, B.; Naluwooza, C.; Acam, C.; Mukankusi, C.Root rots cause severe yield losses of up to >70% in common bean (Phaseolus vulgaris L.) in most parts of the world, with devastating effects on the major commercial bean cultivars in East and Central Africa. Increased intensity of droughts and rains, and higher temperatures influence the occurrence and distribution of root rots, resulting in increased epidemics. The causal pathogens tend to occur in a complex, and since most cultivars do not have broad resistance, adverse effects continue to occur. The objective of this study was to evaluate the levels of dual resistance of new breeding lines (BL) developed for root rot resistance, as well as Andean (ADP) genotypes, for resistance to Fusarium (FRR) and Pythium root rots (PRR). Altogether, 316 new BL developed for root rot resistance and 295 ADP bean genotypes were evaluated at Kawanda in Uganda. There were significant differences (P<0.05) among genotypes for both root rots and yield. Thirty and 1.9 percent of the BL and ADP genotypes expressed resistance to both root rots. In addition, more than 80% of ADP genotypes showed susceptibility to both root rots. Yield was generally poor with means of 458 kg ha-1 for ADP, and ranging from 949 to 1075 kg ha-1 for the BL groups. Nonetheless, the 0.3 and 2.4% of the ADP and BL that yielded >2000 kg ha-1 expressed high yield potential, considering that majority of the genotypes yielded below 1000 kg ha-1.