Browsing by Author "Barekye, Alex"
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Item Assessing New Banana Genotypes for Relevant Traits: Implication for Variety Selection(Agricultural Sciences, 2020) Tumuhimbise, Robooni; Barekye, Alex; Talengera, David; Akankwasa, Kenneth; Nowakunda, Kephas; Asasira, Moreen; Karamura, Deborah; Karamura, EldadUnderstanding the performance of new crop genotypes for traits of relevance is important in selecting potential cultivars to satisfy end-users. The objective of this study was to determine the performance of new banana genotypes for bunch mass (BMS) and BMS-related traits, resistance to black Sigatoka and sensory attributes. Eight cooking banana genotypes consisting of six new hybrid genotypes selected from advanced breeding trials and two control cultivars were evaluated in a randomized complete block design for three crop cycles at three locations in Uganda. Genotype, location, crop cycle and their interaction effects were significantly different for most traits assessed. The overall top two genotypes (“9058K-2” and “8099K-16”) combining high BMS, resistance to black Sigatoka and acceptable sensory attributes were identified. These genotypes are suggested as potential commercial cultivars for release to farmers in Uganda and/or other East African countries with similar environmental conditions to those where the genotypes were tested. It should be noted that high BMS/yield and resistance to diseases are not the only factors to consider when selecting banana genotypes that meet end-user needs. A combination of high BMS/yield, acceptable sensory attributes and resistance to diseases essentially influence the selection process of banana cultivars.Item Bioengineered potato: Resistance to late blight disease and higher crop yields(International Potato Center, 2019) Ghislain, Marc; Barekye, AlexAverage potato yields in sub-Saharan Africa are four times lower than those in industrialized nations, mostly due to the effects of diseases, particularly late blight. This research demonstrates that the transfer from wild potato relatives of three resistance-conferring genes into a cultivated potato variety provides complete resistance to late blight for several seasons. Initial findings suggest this resistance will be long lasting. Cultivation of this late blight resistant potato would increase family farm incomes by 40% and ensure the supply of fungicide-free potatoes to consumers.Item Bridging the gap in quality and quantity of seed potatoes through farmer managed screen houses in Uganda(African Journal of Plant Science, 2017) Byarugaba, Arinaitwe Abel; Kyooma, John; Aheisibwe, Rwaheru Ambrose; Tibanyedera, Deo; Barekye, AlexQuality seed potato is a key factor in enhancing potato yields in Uganda. Available disease-free seed potato accounts for less than 5% of the whole potato seed market demand in Uganda leaving 95% as seed availability gap. This study was conducted to explore the potential of using farmer managed screen houses to alleviate the seed potato availability gap that exists in Uganda. Six screen houses of 7 m × 14 m each with capacity of 1620 plants were set up, three (3) screen houses in Bukimbiri, one (1) in Kisoro, one (1) in Hamurwa and one (1) in Maziba sites. All the sites were managed by trained six famers. Sterilized soil was used to reduce the incidence of pathogens and to ensure that clean minitubers were produced. Seed production was done in 2015 for two consecutive seasons (A and B). From the 6 screen houses, a total of 107,638 clean mini-tubers were generated across the sites for both seasons. At multiplication ratio of 1: 9 the generated mini-tubers have the potential of generating 968,742 tubers. This would reduce on existing seed gap for the next season. It was noted during the study that mini-tuber production, vigour and rate of growth varied significantly (P<0.001) across the varieties with ‘Rwangume’ achieving the highest yield in terms of tuber number per plant and height, compared to other 4 varieties (Kiningi, Rwashaki, Kachpot 1 and Victoria). This study showed that production of disease free mini-tuber at farmer level is possible using screen house technology and has a potential of reducing the seed availability gap through production of quality seed that can be accessed by other farmersItem Combining ability analysis of dry matter content, reducing sugars and yield of potato (Solanum tuberosum L.) genotypes in Uganda(Journal of Scientific Agriculture, 2020) Muhumuza, Edgar; Edema, Richard; Namugga, Prossy; Barekye, AlexPotato (Solanum tuberosum L.) in Uganda is a major food and cash crop mainly grown in the highland regions by small-scale farmers. The increasing importance of potato as a processed product requires new varieties possessing quality processing attributes with acceptable yield. The objectives of this study were to estimate the combining ability effects for dry matter content, reducing sugars, and yield related traits in potato. Nineteen F1 families generated from eight parents using a half diallel mating design were evaluated for dry matter content, reducing sugars, average weight per tuber and total tuber yield at Kachwekano research station. Additive genetic effects were predominant for dry matter content while non-additive effects for the other traits. The GCA/SCA ratios were 0.58, 0.28, 0.17 and 0.44 for dry matter content, reducing sugars, average weight per tuber and total tuber yield respectively. Broad sense heritability estimates were 50.6% for dry matter content, 77.8% for reducing sugars, 90.3% for average weight per tuber and 29.5% for total tuber yield. Parents NAROPOT 3 and 395096.2 had desirable GCA effects for both dry matter content and reducing sugars. Families of nkrk19.17 x Rutuku had desirable SCA effects for dry matter content while Rutuku x 393077.54 and nkrk19.17 x 392657.8 had desirable SCA effects for reducing sugars. Additive genetic effects for dry matter content imply that, genetic gains can be achieved through different selection methods and trait transferred to the respective progenies. The selected parents and families will be subjected to further clonal evaluation and selection.Item Combining ability analysis of earliness and yield of potato (Solanum tuberosum L.) genotype in Uganda(Euphytica, 2018) Namugga, Prossy; Sibiya, Julia; Melis, Rob; Barekye, AlexPotato (Solanum tuberosum L.) is a major food and cash crop mainly grown by small-scale farmers in the highland regions of Uganda. Changing global weather patterns require varieties that are able to grow within the short rainfall cycles and yield optimally under the prevailing conditions. The objectives of this study were to estimate the combining ability effects for early maturity, yield and yield related traits in potato. Eighteen F1 families generated from two sets of 12 parents using a North Carolina Design II were evaluated for days to 50% flowering, leaf senescence, yield and yield related traits in two different locations. Both additive and non-additive genetic effects influenced the expression of traits. However, additive genetic effects were predominant over the non-additive for most of the traits. The GCA/SCA ratios were 0.68 and 0.78 for days to 50% flowering and average tuber weight. Broad sense heritability estimates were 0.70 for total tuber weight and 0.78 for days to 50% flowering. The predominance of additive genetic effects implies that, genetic gains can be achieved through different selection methods and traits transferred to the respective progenies. Parents Rwangume, 396,038.107, 395,011.2, NKRK19.17, 393,077.54, Kimuri, and 392,657.8 had desirable GCA effects for the number of days to flowering and yield-related traits. Families of Rwangume × NKRK19.17, 393,077.54 × 395,011.2, 396,038.107 × Rwangume, and 396,038.107 × 395,011.2 had desirable SCA effects for yield and number of days to 50% flowering. The selected parents and families will be subjected to further clonal evaluation and selection.Item Comparative Phenotypic and Agronomic Assessment of Transgenic Potato with 3R-Gene Stack with Complete Resistance to Late Blight Disease(Biology, 2021) Byarugaba, Arinaitwe Abel; Baguma, Gerald; Mutebi Jjemba, Douglas; Aharinta, Kenneth Faith; Wasukira, Arthur; Magembe, Eric; Njoroge, Anne; Barekye, Alex; Ghislain, MarcTransgenic potato event Vic.172, expressing three naturally occurring resistance genes (R genes) conferring complete protection against late blight disease, was evaluated for resistance to late blight, phenotypic characterization, and agronomic performance in field conditions at three locations during three seasons in Uganda. These trials were conducted by comparison to the variety Victoria from which Vic.172 derives, using identical fungicide treatment, except when evaluating disease resistance. During all seasons, the transgenic event Vic.172 was confirmed to have complete resistance to late blight disease, whereas Victoria plants were completely dead by 60–80 days after planting. Tubers from Vic.172 were completely resistant to LB after artificial inoculation. The phenotypic characterization included observations of the characteristics and development of the stems, leaves, flowers, and tubers. Differences in phenotypic parameters between Vic.172 and Victoria were not statistically significant across locations and seasons. The agronomic performance observations covered sprouting, emergence, vigor, foliage growth, and yield. Differences in agronomic performance were not statistically significant except for marketable yield in one location under high productivity conditions. However, yield variation across locations and seasons was not statistically significant, but was influenced by the environment. Hence, the results of the comparative assessment of the phenotype and agronomic performance revealed that transgenic event Vic.172 did not present biologically significant differences in comparison to the variety Victoria it derives from.Item Factors Influencing Farmers’ Decision to Adopt Apple Management Practices in Southwestern Highlands, Uganda(Journal of Economics and Sustainable Development, 2019) Rwaheru Aheisibwe, Ambrose; Tindimwebwa, Kenneth; Ashaba, Denis; Barekye, AlexWorldwide apples account for fifty (50) percent of the world’s deciduous fruit tree production. Despite the benefits that come with apple production, adoption has been slow especially among smallholder farmers in Southwestern Highlands. This present study was therefore conducted to identify apple management practices (AMPs) and also examine the factors influencing farmer decision to adopt AMPs. A multi-stage sampling procedure was employed to select 52 apple growing households in the districts of Kabale, Kisoro, Kanungu and Rukungiri that form Southwestern Highlands. Probit regression model was employed and the estimation procedure followed Maximum Likelihood Estimation (MLE) approach. Results from the descriptive statistics indicated that the most applied management practices included weeding, bending and staking, pesticide application and defoliation among others. Probit regression results showed that sex of the farmer, average number of fruits per tree, household labor force, farm size and access to credit had a positive and statistically significant effect on farmers’ decision to adopt AMPs (p<0.05) while age of the farmer, orchard location, obstruction by birds and off-farm income source had a negative and statistically significant influence on farmers’ decision to adopt AMPs (p<0.05). In view of the above, there is need to identify and address gender differences in terms of engagement in apple production targeting more women. Research needs to come up with an effective but affordable remedy against pests especially birds, strategies of attracting and maintaining youth into apple farming need to be explored and implemented since apple farming is labor intensive and is dominated by aging farmers, research and extension need to explore appropriate and cost effective avenues for farmers to access credit, accurate and quality agricultural information.Item Fish Species Composition, Abundance and Diversity of Minor Lakes in South Western Uganda/Kigezi Region(International Journal of Science and Technology, 2015) Tibihika, Papius, D. M.; Barekye, Alex; Byakora, EzraFish is one of the commodities that can reduce poverty and malnutrition in Southwestern Uganda. The presence of rich aquatic bodies in this region is a good resource for capture fisheries. The current study investigated fish species composition, abundance and diversity in six lakes, Mutanda, Mulehe, Chahafi, Kayumbu, Bunyonyi and Nakasanda in the region. Qualitative and quantitative data were collected using structured interview questions and various gears, gill nets, hooks, basket traps and beach seine nets. The results showed that, minor lakes in the region had a diverse fish community consisting of 8 species, Small species of Barbus, Clarias carsoni, Cray fish, Haplochromines, Oreochromis leucostictus, Oreochromis niloticus, Clarias gariepinus and Tilapia zilli. Out of these, only three (3), Barbus, Haplochromines and Oreochromis niloticus, appeared in all the lakes. Haplochromines were the most abundant fish species. Nile tilapia was more abundant in Lake Kayumbu. Lake Mutanda had more fish species richness and Lake Nakasanda demonstrated a more species evenness and diversity. The results from the current study, suggest that the minor lakes could serve as important sources of fish for both the riparian communities and the country at large if appropriate management interventions are instituted.Item Genetic Analysis of Weevil (Cosmopolites Sordidus) Resistance in an F2 Diploid Banana Population(Journal of Plant Breeding and Genetics, 2015) Arinaitwe, Ivan K.; Barekye, Alex; Kubiriba, Jerome; Sadik, Kassim; Karamura, Eldad; Edema, RichardThe East African highland bananas (Musa spp. AAA), an important staple food in Uganda, are highly susceptible to the banana weevil (Cosmopolites sordidus Germar). Sources of host plant resistance to the banana weevil exist in wild diploid bananas. The use of wild diploid bananas to improve East African highland bananas can be facilitated by studying genetics of host plant resistance of inter-diploid crosses. The objectives of this study were a) to identify segregating weevil resistance and agronomic traits in an F2 diploid population, and, b) to determine the inheritance of banana weevil resistance and agronomic traits based on an F2 banana diploid population. An F1 population developed from Musa acuminata subsp. banksii acc. Kasaska (ITC0591) and M. acuminata subsp. microcarpa acc. Borneo (ITC0253) was selfed to generate an F2 diploid population. The F2 population was screened against weevil resistance and agronomic traits in the laboratory, pot and field experiments. There were significant differences (P < 0.05) among the different genotypes for banana weevil resistance traits such as head capsule width, body length, body weight, larval mortality, total damage, peripheral damage, dead weevils and larvae retrieved. There were also significant differences (P < 0.05) for agronomic traits such as inner corm hardness and total corm hardness. The histograms for the banana weevil resistance traits such as head capsule width, body length, body weight and larval mortality, total damage, peripheral damage, cross sectional inner and outer damage, larvae retrieved and dead weevils showed continuous distribution. Similarly, histograms for agronomic parameters such as height of plant at flowering and girth at 1 meter at flowering showed continuous distribution. The Chi-square test of goodness of fit indicated that weevil growth and damage parameters had significant modifications of the expected 9:3:3:1 ratio for two independent loci, thus suggesting epistasis affects their inheritance.Item Genetic Characterisation and Diversity Assessment of Potato Genotypes Using SSR Markers(Journal of Agricultural Science, 2017) Namugga, Prossy; Sibiya, Julia; Melis, Rob; Barekye, AlexInformation on diversity of genetic materials is vital for choosing parents in a breeding program. The objective of the study was to determine the pattern and level of genetic diversity among the selected 20 tetraploid potato genotypes using 16 SSR markers to identify suitable parents for breeding purposes. The microsatellites showed considerable variation among genotypes and sixty four alleles were amplified by the 16 primer pairs. The number of polymorphic alleles per locus ranged from 2 to 8 with an average of 3.9. The highest number of null alleles was observed was six for genotype Nakpot1. The overall size of the amplified product varied from 48 bp (marker STI0023) to 309 bp (marker STM5121). PIC values ranged from 0.0948 to 0.7832, with an average of 0.4307 per locus. Heterozygosity values ranged from 0.0997 to 0.805 with an average of 0.466919. Significant positive linear correlations were observed between PIC values and number of alleles (r = 0.905); and heterozygosity and number of alleles (r = 0.8659) at p < 0.001. Cluster analysis separated the genotypes into three different groups. The genetic distance between clones ranged from 1 to 5.7. Cruza had the highest genetic distance while the shortest genetic distance was observed between 396026.103 and 396034.104. The microsatellites used in this study provided useful information regarding the variability of the tested genotypes and their selection for breeding purposes.Item Genotype by environment interaction (GxE) as a measure of yield stability of Dutch potato varieties in Uganda(African Journal of Agricultural Research, 2018) Byarugaba, Arinaitwe Abel; Benon, Mateeka; Tibanyedera, Deo; Barekye, AlexTwenty one (21) Dutch potato varieties were introduced in Uganda during 2015-2016 seasons for national yield performance and adaptability studies so that most stable varieties could be identified for production. The effect of genotype (G), environment (E) and their interaction (G x E) on tuber yield was assessed to establish variety adaptation in different agro ecologies. Five sites were used in the study that included; Kalegyere (2450 m/asl), Kachwekano (2225m/asl), Rwebitaba (1531m/asl), Buginyanya (1887m/asl) and Zeu-DFI (1642m/asl). The varieties that yielded highest were; El-mundo (22 t ha-1), Sarpomira (22 t ha-1), Connect (21.7T/ha), Rudolph (21.4t ha-1), Arizona (20.3 t ha-1), Voyager (20 t ha-1), Faluka (19.9 t ha-1) and Sagitta (19.9 t ha-1). GxE analysis was done using Additive main effects and multiplicative interaction (AMMI) and results showed that GxE interaction accounted for 12.6% of the total variation, while genotypes and environments accounted for 5.7% and 59.7% of the total variation respectively. The AMMI bi-plots identified varieties Caruso, Derby, Voyager, Royal, Navigator, Manitou, Destiny, Musica and Markies to have the lowest (0.00033-0.6609) IPCA 1 score hence were most adapted. Varieties Rwagume, Sarpo Mira, Connect and Kachpot 1 were more adapted at Kalegyere site (-3.601 IPCA1 score) while Sarpo Mira, Connect, El-Mundo and Rudolph were adapted at Kachwekano site (-0.562 IPCA1 score). Varieties Arizona, Faluka, Panamera and Connect were adapted at Zeu (0.125 IPCA1 score). Varieties El-Mundo, Arizona, Rudolph and Connect were more adapted at Buginyanya ZARDI (0.498 IPCA1 score) while El-Mundo, Rudolph, Sagitta and Royal most adapted at Rwebitaba ZARDI (3.54 IPCA1 score). The most interactive genotype was Rwagume with interaction score of - 2.30516 while the least interactive genotype were Caruso and Taurus with IPCA 1 score of 0.00033 and 0.01086 respectively.Item Genotypic variability estimates of agronomic traits in secondary triploid banana ‘Matooke’ (Musa sp., AAAEA) hybrids(African Journal of Plant Science, 2016) Tendo Ssali, Reuben; Barekye, Alex; Buregeya, Henry; Erima, Rockefeller; Namanya, Priver; Kubiriba, JeromeEffective selection of hybrids for a trait is based on the extent of variation and heritability. This study examined yield parameters of secondary triploid ‘Matooke’ hybrids and the extent of their genetic diversity based on the traits evaluated. Eleven genotypes, including nine ‘Matooke’ hybrids and two landraces were evaluated for 12 characters in a preliminary yield trial (PYT) over three crop cycles. Plant height, bunch weight, number of standing leaves at flowering and the youngest leaf spotted with black Sigatoka symptoms showed significant interaction between genotype and crop cycle. While characters such as pseudo stem girth, number of days for fruit filling, number of hands, number of fingers on the second hand and the fruit length showed stable differences amongst these genotypes. The genotypic coefficient of variation for the characters ranged from 7.6% (finger length) to 33.5% (bunch weight); with moderate heritability estimates varying from 13.5% (pseudostem girth) to 67% (plant height). Bunch weight showed strong positive correlation with number of hands, number of fingers on the second hand, the fruit length and pseudostem girth. These results imply that breeders could select for some of these variable and ratoon stable traits in a single cycle of early evaluation trial, subsequently reducing costs, time and space in field testing.Item Interactive effects of Potato virus Y and Potato leafroll virus infection on potato yields in Uganda(Open Agriculture, 2020) Byarugaba, Arinaitwe Abel; Mukasa, Settumba B.; Barekye, Alex; Rubaihayo, Patrick R.Potatoes are prone to attack by multiple viruses, which contribute greatly to yield and quality decline depending on the cultivar and the virus involved. This study investigated the effect of co-infection involving Potato virus Y (potyvirus) and Potato leafroll Virus (pelero virus) on productivity of five potato cultivars in Uganda and the nature of virus interaction during co-infection process. Variety response to virus infection by PVY, PLRV and co-infection (PVY + PLRV) varied across different varieties. The plants that were infected with PLRV had leaf rolling, stuntedness, leaf distortion, reduction in leaf size and mottling and light yellow mosaics, and in some cases, purple or red margins were observed, while single infection of PVY induced necrosis, leaf rugosity, crinkling, stunting, interveinal necrosis, blotching of the margins, leaf distortion andmottling. When the two viruses were combined during co-infection with PVY + PLRV, the symptoms were characterized by bright blotching and necrotic leaf margins with purpling of the leaf tips and leaf margins, stuntedness and leaf distortions. The virus disease severity was higher under mixed infected plants than single infected plants. The high disease severity culminated in a significant effect on yield, marketable tuber number per plant, plant growth height and plant vigor, which were different across the varieties. Co-infection involving PVY and PLRV caused a reduction in the marketable yield of 95.2% (Kinigi), 94% (Victoria), 89.5 (Rwagume), 45.3% (Royal) and 23.7% (Sifra). Single infection by PLRV caused a reduction in amarketable yield in Victoria (91.8%), Kinigi (84.8%), Rwagume (73.3%), Royal (47.2%) and Sifra 22.1%, while PVY caused a marketable yield reduction in Victoria (87.2%), Rwagume (85.9.7%), Kinigi (85.1%), Royal (37.4%) and Sifra (14.1%). The effects associated with the coinfection of PVY and PLRV were lower than the combined value of the single infections, suggesting that the two viruses were interacting to affect the potato productivity. The high yield loss suggested that effective resistance strategy targeting PVY, PLRV and their combination was required to save the potato industry in Uganda.Item ‘Kiwangaazi’ (syn ‘KABANA 6H’) Black Sigatoka Nematode and Banana Weevil Tolerant ‘Matooke’ Hybrid Banana Released in Uganda(HortScience, 2015) Nowakunda, Kephas; Barekye, Alex; Ssali, Reuben T.; Namaganda, Josephine; Tushemereirwe, Wilberforce K.; Nabulya, Gertrude; Erima, Rockefeller; Akankwasa, Kenneth; Hilman, EdisonThis article presents the attributes of the first East African highland banana hybrid, ‘Kiwangaazi’ (Fig. 1), which was recently selected, released, and added to the national cultivar list in Uganda. The ‘matooke’ hybrid ‘Kiwangaazi’ was conventionally bred at Kawanda by crossing the tetraploid hybrid ‘1201k-1’ (‘Nakawere’ AAA · ‘Calcutta4’ AA) with the improved diploid ‘SH3217’ AA. The main target was black Sigatoka resistance, a disease caused by the fungal pathogen Mycosphaerella fijiensis, ranked as the most important constraint to the production of the East African highland bananas, especially in the low lands (covering most of central and eastern Uganda). ‘Kiwangaazi’, together with other hybrids was evaluated for black Sigatoka response, nematode andweevil damage, yield, and consumer acceptability.Item Management of potato leaf miner in Uganda(African Journal of Agricultural Research, 2019) Rose, Mwesige; Barekye, Alex; Joseph, Etiang; Gerald, Kwikiriza; Innocent, Uzatunga; Sarah, KyarisiimaThe yield of potato, an important food security and income crop in Uganda is substantially affected by pests. A survey was carried out in south western Uganda, a major potato growing area to assess the distribution and severity of potato pests in June and July 2015. In addition, leaf miner management options such as pesticide use, yellow sticky traps and mulching were evaluated for effectiveness. Trials in leaf miner hot spots in Bukimbiri and Chahi sub-counties of Kisoro district were conducted in three seasons during 2016 to 2017. In each sub-county, two sites were selected per season and trials were established in a completely randomized design with each treatment being replicated three times. From the survey, aphids and leaf miners were the major pests with high incidences in Kabale and Kisoro districts and rarely encountered in Rukungiri and Kanungu. Use of Dudu-acelamectin reduced leaf miner damage on leaves in season 1 (2017; P=0.001) and registered significantly higher yields compared to other treatments. Yellow sticky traps trapped high leaf miner fly populations but leaf miner damage on leaves and yield were not significantly different from control and mulched plots. Judicious use of pesticides in high leaf miner populations together with yellow sticky traps can reduce leaf miner populations and damage on potato.Item ‘NABIO808’ (Syn. ‘NAROBAN5’): A tasty cooking banana cultivar with resistance to pests and diseases(Crop Breeding and Applied Biotechnology, 2019) Tumuhimbise, Robooni; Buregyeya, Henry; Kubiriba, Jerome; Tushemereirwe, Wilberforce K.; Barekye, Alex; Tendo, Reuben S.; Namagembe, Betty; Muhangi, Sedrach; Kazigye, Francis; Talengera, David; Tindamanyire, Jimmy; Akankwasa, Kenneth; Nabulya, Gertrude; Namaganda, Josephine; Waswa, William; Kushaba, Abias; Namuddu, Mary; Oyesigye, Naboth; Namanya, Priver; Arinaitwe, Ivan K.; Waniale, Allan; Karamura, Deborah; Karamura, Eldad‘NABIO808’ is a newly released, conventionally-bred triploid cooking banana cultivar in Uganda. It produces an average bunch yield of 54.5 t ha-1 yr-1 and is resistant to weevils, nematodes, and black Sigatoka. Additionally, its food is yellow, soft, and tasty, like that of most preferred landrace cultivars, making it more acceptable to end-users.Item New High-yield Cooking Banana Cultivars with Multiple Resistances to Pests and Diseases (‘NAROBan1’, ‘NAROBan2’, ‘NAROBan3’, and ‘NAROBan4’) Released in Uganda(HortScience, 2018) Tumuhimbise, Robooni; Barekye, Alex; Kubiriba, Jerome; Akankwasa, Kenneth; Arinaitwe, Ivan K.‘NAROBan1’, ‘NAROBan2’, ‘NAROBan3’, and ‘NAROBan4’ are secondary triploid cooking banana cultivars. They were bred by the National Agricultural Research Organisation (NARO) in Uganda, and officially released and added to the national cultivar list by the Ministry of Agriculture, Animal Industry and Fisheries (MAAIF) in 2017. The cultivars are highly resistant to black Sigatoka, a fungal disease caused by Mycosphaer- ella fijiensis (Morelet), which was the main breeding target. In addition, they are resistant to the banana weevil Cosmopolites sordidus (Germar) and nematodes, the pests of most economic concern in banana production, especially in the lowland areas of central and eastern Uganda. Compared with the local cultivars, which have an average bunch yield of less than 30% of their potential of 60 to 70 t/ha/year, ‘NAROBan1’, ‘NAROBan2’, ‘NAROBan3’, and ‘NAROBan4’ produce average bunch yields of 54.9 t/ha/year, 60.4 t/ha/year, 64.7 t/ha/year, and 68.8 t/ha/year, respectively. Moreover, they have soft, tasty, aromatic, and near-yellow food colors, which make them appreciated like the existing farmer-accustomed local cooking banana cultivars that have, however, a low yield and are susceptible to pests and diseases.Item Performance of Narita Banana Hybrids in the Preliminary Yield Trial for Three Cycles in Uganda(NARO, 2015) Tushemereirwe, Wilberforce; Batte, Michael; Nyine, Moses; Tumuhimbise, Robooni; Barekye, Alex; Ssali, Tendo; Talengera, David; Kubiriba, Jerome; Lorenzen, Jim; Swennen, Rony; Brigitte, UwimanaBananas (Musa spp.) are an indispensable part of life in Eastern Africa providing up to one fifth of total calorie consumption per capita. Unlike many staple crops, bananas deliver food throughout the year, making them an ideal crop for household incomes, food and nutrition security. However, banana yields are low due to several factors amongst others pests and diseases: weevils and nematodes, Fusarium wilt, bacterial wilt and black Sigatoka. There are many potential technology-based interventions for increasing banana yields but host plant resistance is the most appropriate and cost effective intervention given the current stage of development of banana systems in the region. Host-plant resistance also offers significant spill over benefits for human health and positive environmental impacts. Therefore, the Ugandan National Agricultural Research Organization (NARO) and the International Institute of Tropical Agriculture (IITA) jointly breed bananas largely for host-plant resistance to improve banana yields. One of the most important current products of their joint banana breeding efforts is secondary triploid hybrids for food and juice herein referred to as NARITA hybrids. This name specifies the contribution of NARO and IITA. An earlier report (NARITA report 1) presented the results of 25 NARITA hybrids for cycles 1 and 2 combined. The current report presents and discusses the results of the same 25 NARITA hybrids (18 for food and seven for juice) evaluated for three crop cycles at Sendusu in central Uganda and analyzed in combined and separate forms. Results of individual NARITA hybrids within cycles showed high degree of variation for the traits assessed, implying a high potential for selection among the NARITA hybrids evaluated. For example, the bunch weight (BWT) of the individual NARITA hybrids ranged from as low as 5 kg for NARITA 19 to as high as 45 kg for NARITA 24 with a mean of 17.8 kg. Averaged across three cycles, BWT ranged from as low as 8.7 kg for NARITA 19 to as a high as 30.4 kg for NARITA 24. Ninety six per cent of the hybrids had a mean BWT greater than the mean of the local check (Mbwazirume) (11.0 kg). Similarly, NARITA hybrids were better than Mbwazirume for most of the other traits assessed. Eighty four per cent of the NARITA hybrids evaluated were better than the best founder parent (NFUUKA) for bunch yield (t ha-1), indicative of the significant breeding progress made by NARO and IITA in this breeding program. This could be confirmed by the positive better founder parent heterosis for BWT recorded by all NARITA hybrids, with NARITA 17, NARITA 18, NARITA 7 (M9), NARITA 21 and NARITA 14 (all food type) exhibiting highest heterosis. Results of combined analysis of variance (ANOVA) showed significant differences among the NARITA hybrids for all the 14 traits assessed including BWT. This indicated the potential for further selection and improvement of the NARITA hybrids for all the 14 traits. Additionally, results of combined ANOVA showed significant differences among three crop cycles for all the traits assessed except days to bunch maturity (DTM) and number of functional leaves at flowering (NFLF), indicating that the selection of banana hybrids could best be done at certain cycle numbers. The performance of NARITA hybrids for most traits was much higher at cycles 2 and 3 than at cycle 1 with the highest performance observed at cycle 3. However, the difference between cycle 2 and cycle 3 was not significantly different for most traits including BWT. The clear implication of this is that selection for banana hybrids should be done at cycle 2 to reduce costs involved in the management of trials since banana trials are always huge considering the size of bananas as well as spacing of 3 x 3 m or 2 x 3 m commonly used. Also, banana performance data analysis should not be based on a combined evaluation of cycle 1 and 2, as was previously done for NARITA report 1, but on an analysis of individual cycles, preferably cycle 2. The limitation of single site and single line plots is acknowledged. Hence, NARITA hybrids will be evaluated in larger and replicated multi-location trials to ascertain their actual performance, adaptability and stability in comparison with the local EAHB cultivars. Nevertheless, based on these preliminary results, potential high yielding banana hybrids combining resistance to black Sigatoka and farmer-preferred quality traits exist within this NARITA population.Item Phenotypic characterisation of potato (Solanum tuberosum) genotypes in Uganda(South African Journal of Plant and Soil, 2017) Namugga, Prossy; Sibiya, Julia; Melis, Rob; Barekye, AlexIdentification of genetic variation and interrelationships among germplasm collections is essential for parental selection and trait identification among parents for use in breeding programmes. The aim of this study was to characterise 48 potato genotypes to identify suitable parents for crop improvement purposes. Genotypes were evaluated in the field using an alpha lattice design with three replications at the Kachwekano and Karengyere research stations in Uganda. Site had significant effects on genotype performance for all measured parameters. Genotypic effects were significant (p < 0.01) for total tuber yield, main stem number and plant height. The mean tuber yield for the two sites was 29.8 t ha−1 and tuber yield was higher in Kachwekano than Karengyere. The highestyielding genotype in Kachwekano was 396038.105 (54.5 t ha−1) and in Karengyere was NAKPOT5 (50.9 t ha−1). Significant positive correlations (p ≤ 0.001) were observed between tuber yield and plant height; duration of flowering, and days to flowering and plant height. The most stable genotypes with regard to tuber yield were Rutuku, 395112.32, 395017.14 and 393220.54. Cluster analysis revealed three principal clusters with nine subclusters. Variation for the different traits exhibited by genotypes in this study should be exploited in crop improvement programmes.Item Prevalence of R Genes for Resistance to Potato Viruses in Uganda Germplasm(Potato Research, 2021) Byarugaba, Arinaitwe Abel; Mukasa, Settumba B.; Barekye, Alex; Rubaihayo, Patrick R.The most important potato viruses in Uganda are Potato virus Y (PVY), Potato leaf roll virus (PLRV), Potato virus X (PVX), Potato virus S (PVS), Potato virus A (PVA) and Potato virus M (PVM). Utilization of R genes in breeding for resistance to viruses has not been explored in Uganda due to limited information on the prevalence of R genes in the available genotypes. This study aimed at identifying potato genotypes with R genes for resistance to potato viruses important in Uganda. The study screened 71 potato accessions from the National Potato Breeding Programme at Kachwekano Zonal Agricultural Research and Development Institute for the presence of resistance genes to viruses using diagnostic molecular markers. The results indicated that 21 out of 71 genotypes had resistance markers, of which nine genotypes, NKRN59.58, Derby, Markies, Sifra, 395017.229, Nakpot 5, 20108.5, Royal and 393220.54, had Ryadg gene for PVY resistance and two genotypes, Kimuri and 319919.3, had Rysto gene for resistance to PVY and PVA. Nine genotypes, 395011.2, Markies, Nakpot 5, 20108.5, Sifra, 20157.6, Royal, 2015.8 and Ambition, had the Nbtbr gene for resistance to PVX. In addition, 14 genotypes, 395011.2, Markies, Nakpot 5, Sarpouna, 393220.54, 391046.14, Sarpomira, 395077.12, Sifra, 20157.6, Royal, Ambition, Kimuri and Caruso, had the Nsadg gene conferring resistance to PVS. Four genotypes, Markies, Sifra, Nakpot 5 and Royal, had the Ryadg, Nbtbr and Nsadg genes for combined resistance to PVY, PVX and PVS. The resistant genotypes could be used as parents to introgress resistance genes into susceptible cultivars.