Browsing by Author "Rubaihayo, Patrick"
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Item Additive Main Effects and Multiplicative Interactions Analysis of Yield Performances in Cowpea Genotypes under Ugandan Environments(International Journal of Advanced Research (IJAR), 2017) Agbahoungba, Symphorien; Karungi, Jeninah; Talwana, Herbert; Badji, Arfang; Kumi, Frank; Mwila, Natasha; Edema, Richard; Gibson, Paul; Rubaihayo, PatrickYield in legumes is the result of many plant processes, which are usually expressed in yield and have been shown to be affected by management, genotype and environment. The objectives of this study were to assess the extent of genotype x environment interaction and to select the stable cowpea genotypes in Ugandan environments over seasons. Seventy-two cowpea genotypes were evaluated for yield in three locations and two seasons in Uganda. The yield data were subjected to analysis of variance and additive main effects and multiplicative interactions (AMMI) analysis. The results showed a highly significant (P<0.001) genotype by location and by year (season) interaction effects for grain yield, with 69.16% of the total variation attributable to environmental effects, 5.36% to genotypic effects and 12.74% to G x E interactions effects. Genotype MU9 had the highest yield (854.68 kgha-1) but was only adapted to specific environments (Arua 2015B and 2016A). Hence, genotypes WC 30, NE 45, NE 31, NE 51 which were equally high yielding, stable and adapted to the tested environments, and should be recommended for genetic improvement of cowpea germplasm in Uganda.Item Combining Ability and Gene action for Resistance to Fusarium ear rot in tropical maize hybrids(Frontiers in Plant Science, 2025-01-30) Ayesiga, Stella Bigirwa; Rubaihayo, Patrick; Dramadri, Isaac Onziga; Sserumaga, Julius PytonA comprehensive understanding of the genetics of resistance is essential for developing an effective breeding strategy to create germplasm resistant to Fusarium Ear Rot. This study aimed to determine the general combining ability (GCA), specific combining ability (SCA), and heritability of resistance to infection by Fusarium verticillioides in tropical maize. Using the North Carolina II mating design, six inbred lines as females and seven as males were crossed to produce 42 hybrids, which were evaluated across five environments using artificial inoculation. At harvest, the hybrids were scored for Fusarium Ear Rot (FER) infection using a 1-9 severity scale. Significant GCA effects for the parents and SCA effects for the hybrids were observed. The narrow-sense heritability estimate was 0.22, while the broad-sense heritability was 0.73, and the additive genetic effects, as represented by GCA (m+f), were more significant than non-additive effects. The inbred parents JPS25-13, JPS26-125, JPS26-86, JPS25-11, JPS25-5, JPS25-7, and JPS25-9 were identified as the best general combiners for FER resistance. These lines, with favorable general combining ability effects for resistance to Fusarium verticillioides, are strong candidates for breeding resistant varieties.Item Combining Ability and Heterosis of Selected Grain and Forage Dual Purpose Sorghum Genotypes(Journal of Agricultural Science, 2017) Chikuta, Sally; Odong, Thomas; Kabi, Fred; Rubaihayo, PatrickSorghum is an important food and feed source in mixed crop-livestock production systems where its dual usage is a preferred option, especially among the resource poor small-scale farmers. Attempts to improve fodder quality traits in maize have been at the expense of grain traits and vice versa, but other studies demonstrated that it was possible to select for high stem biomass without compromising the improvement of grain yields in sorghum. As a follow up to this effort, this study was undertaken to estimate the combining ability of grain and forage sorghum genotypes and determine heterosis for several traits as a criteria for improving dual purpose sorghum cultivars. Four grain and four forage sorghum cultivars were crossed to generate 23 crosses following the half diallel mating design scheme at Makerere University Agricultural Research institute Kabanyolo (MUARIK) in 2013. The crosses were evaluated at three locations in Uganda during two rainy seasons of 2014. Data were taken and analysed on leaf area, leaf-stem ratio, plant height, seed weight, grain yield, and biomass. Results indicated that the gene action for the traits under observation was controlled by both additive and non additive genetic effects. Majority of the parental lines had significant GCA estimates for all traits except line 20 for grain yield, lines 22 and 34 for plant height, line 35 for leaf-stem ratio, and line 22 for days to flowering. Significant (P ≤ 0.05) SCA estimates were prominent in most of the individual parental combinations for all traits except leaf area and leaf-stem ratio indicating the role of dominance gene action. Bakers ratio and heritability coefficients were 52% for biomass, flowering duration and plant height indicating that genetic gains can be achieved by conventional breeding for the three traits. Heterosis in grain yield and biomass over both the mid and better parents was shown by more than half of the crosses studied. This study suggested that both inter and intra allelic interactions were involved in the expression of the traits.Item Development of two high-yielding, consumeracceptable apple banana hybrids (Musa species, AAB genome group) with resistance to Fusarium oxysporum f. sp. cubense race 1(Journal of Plant Breeding and Crop Science, 2018) Buregyeya, Henry; Tumuhimbise, Robooni; Kubiriba, Jerome; Talengera, David; Nowankunda, Kephas; Arinaitwe, Geofrey; Tushemereirwe, Wilberforce K.; Karamura, Deborah; Karamura, Eldad; Rubaihayo, PatrickFusarium wilt of bananas (Musa species) is caused by Fusarium oxysporum f. sp. cubense (Foc). Foc race 1 in particular affects dessert bananas in Uganda, causing >60% yield loss. This study was conducted to assess the performance of two new apple banana genotypes for bunch yield, resistance to Foc race 1 and consumer acceptability. The new apple banana genotypes (NAMU1 and NAMU2), along with two check cultivars, one susceptible but preferred by consumers (Sukali ndiizi) and the other resistant (Yangambi-KM5), were evaluated at the National Agricultural Research Laboratories in Uganda. Bunch yields of the two new apple bananas were higher than those of check cultivars by >50%. NAMU1 and Yangambi-KM5 showed no symptoms of Foc race 1, whereas NAMU2 showed mild symptoms on its corms. Sukali ndiizi showed severe pseudostem splitting and corm discoloration as the key symptoms of Foc race 1. The consumer acceptability of NAMU1 and NAMU2 was as high as that of Sukali ndiizi, implying that they can be perfect substitutes for the Foc race 1 susceptible Sukali ndiizi.Item Estimates of combining ability and heritability in cowpea genotypes under drought stress and nonstress conditions in Uganda(Journal of Plant Breeding and Crop Science, 2017) Mwale, Saul Eric; Ochwo Ssemakula, Mildred; Sadik, Kassim; Alladassi, Boris; Rubaihayo, Patrick; Gibson, Paul; Singini, Wales; Edema, RichardCowpea is an important source of food and income for small scale farmers in Uganda. Production is, however, affected by both biotic and abiotic stresses. Drought stress has recently emerged as a serious concern due to the effects of climate change. This study was therefore undertaken to estimate the general and specific combining ability effects of parents and crosses as well as estimate the heritability of delayed leaf senescence, seed yield and its components under drought stress. Five drought tolerant genotypes were crossed with four drought sensitive genotypes in a North Carolina II mating design. The study revealed that drought tolerance is conditioned by both additive and non-additive genetic effects with the predominance of non-additive genetic effects for seed yield, 100 seed weight and number of pods per plant. Delayed leaf senescence was however, controlled by additive genetic effects, implying that progenies performance could be predicted from parents General Combining Ability (GCA) effects. The cultivars SECOW 5T, IT93K-452-1 and IT98K-205-8 were good combiners for drought tolerance. The F2 families: SECOW 3B x IT98K-205-8, SECOW 5T x IT98K-205-8, SECOW 4W x IT98K- 205-8 and SECOW 1T x IT98K-205-8 had positive Specific Combining Ability(SCA) effects in seed yield, number of pods per plant and 100 seed weight, implying that they performed better than what was predicted by their parents GCA effect. As such, they are promising cross combinations that can be advanced for later generation selection.Item Factors Influencing Genomic Prediction Accuracies of Tropical Maize Resistance to Fall Armyworm and Weevils(Plants, 2021) Badji, Arfang; Machida, Lewis; Kwemoi, Daniel Bomet; Kumi, Frank; Okii, Dennis; Mwila, Natasha; Agbahoungba, Symphorien; Ibanda, Angele; Bararyenya, Astere; Ndapewa Nghituwamhata, Selma; Odong, Thomas; Wasswa, Peter; Otim, Michael; Ochwo-Ssemakula, Mildred; Talwana, Herbert; Asea, Godfrey; Kyamanywa, Samuel; Rubaihayo, PatrickGenomic selection (GS) can accelerate variety improvement when training set (TS) size and its relationship with the breeding set (BS) are optimized for prediction accuracies (PAs) of genomic prediction (GP) models. Sixteen GP algorithms were run on phenotypic best linear unbiased predictors (BLUPs) and estimators (BLUEs) of resistance to both fall armyworm (FAW) and maize weevil (MW) in a tropical maize panel. For MW resistance, 37% of the panel was the TS, and the BS was the remainder, whilst for FAW, random-based training sets (RBTS) and pedigree-based training sets (PBTSs) were designed. PAs achieved with BLUPs varied from 0.66 to 0.82 for MW-resistance traits, and for FAW resistance, 0.694 to 0.714 for RBTS of 37%, and 0.843 to 0.844 for RBTS of 85%, and these were at least two-fold those from BLUEs. For PBTS, FAWresistance PAs were generally higher than those for RBTS, except for one dataset. GP models generally showed similar PAs across individual traits whilst the TS designation was determinant, since a positive correlation (R = 0.92***) between TS size and PAs was observed for RBTS, and for the PBTS, it was negative (R = 0.44**). This study pioneered the use of GS for maize resistance to insect pests in sub-Saharan Africa.Item Fusarium oxysporum Race 1 resistance and quality traits variations in apple banana germplasm(Journal of Plant Breeding and Crop Science, 2020) Buregyeya, Henry; Tumuhimbise, Robooni; Matovu, Moses; Tumwesigye, Kashub S.; Kubiriba, Jerome; Nowankunda, Kephas; Tushemereirwe, Wilberforce K.; Karamura, Deborah; Karamura, Eldad; Kityo, Robert M.; Rubaihayo, PatrickMusa species, AAB genome group, commonly known as Sukali Ndizi (SND) in Uganda, has attained a substantial commercial value in the recent past owing to its superior fruit quality attributes and better prices. However, its sustainable production and productivity are highly threatened by Fusarium wilt. To facilitate large scale area expansion of this important dessert banana, the present study was carried out to identify the near-ideotypic lines of best quality fruit traits that are also resistant to Fusarium wilt. Nineteen SND ecotypes were subsequently collected from nine key SND growing districts of Uganda and evaluated in the field and laboratory for different fruit quality attributes and response to Fusarium wilt. Results showed a wide diversity among SND ecotypes for fruit-quality traits (fruit pulp texture, flavor and taste). The ecotypes were, however, not significantly different (p > 0.05) for susceptibility to FOC race 1. Cluster analysis based on organoleptic and physio-chemical properties grouped the 19 ecotypes into two major-clusters, each of which was also split into two sub-clusters. Individual subclusters summarize levels of similarity amongst the different ecotypes. The study confirmed the presence of diversity in SND germplasm that could be exploited for SND genetic improvement of the crop through hybridization and selection.Item Genetic diversity and population structure of Peronosclerospora sorghi isolates of Sorghum in Uganda(International Journal of Environment, Agriculture and Biotechnology (IJEAB), 2018) Kumi, Frank; Agbahoungba, Symphorien; Badji, Arfang; Mwila, Natasha; Ibanda, Angele; Anokye, Michael; Odong, Thomas; Wasswa, Peter; Ochwo- Ssemakula, Mildred; Tusiime, Geoffrey; Biruma, Moses; Kassim, Sadik; Rubaihayo, PatrickSorghum is the third most important staple cereal crop in Uganda after maize and millet. Downy mildew disease is one of the most devastating fungal diseases which limits the production and productivity of the crop. The disease is caused by an obligate fungus, Peronosclerospora sorghi (Weston & Uppal) with varying symptoms. Information on the genetic diversity and population structure of P.sorghi in sorghum is imperative for the screening and selection for resistant genotypes and further monitoring possible mutant(s) of the pathogen. Isolates of P. sorghi infecting sorghum are difficult to discriminate when morphological descriptors are used. The use of molecular markers is efficient, and reliably precise for characterizing P. sorghi isolates. This study was undertaken to assess the level of genetic diversity and population structure that exist in P. sorghi isolates in Uganda.Item Genetic Gains for Yield and Virus Disease Resistance of Cassava Varieties Developed Over the Last Eight Decades in Uganda(Frontiers in Plant Science, 2021) Manze, Francis; Rubaihayo, Patrick; Ozimati, Alfred; Gibson, Paul; Esuma, Williams; Bua, Anton; Alicai, Titus; Omongo, Chris; Kawuki, Robert S.Achieving food security for an ever-increasing human population requires faster development of improved varieties. To this end, assessment of genetic gain for key traits is important to inform breeding processes. Despite the improvements made to increase production and productivity of cassava in Uganda at research level, there has been limited effort to quantify associated genetic gains. Accordingly, a study was conducted in Uganda to assess whether or not genetic improvement was evident in selected cassava traits using cassava varieties that were released from 1940 to 2019. Thirty-two varieties developed during this period, were evaluated simultaneously in three major cassava production zones; central (Namulonge), eastern (Serere), and northern (Loro). Best linear unbiased predictors (BLUPs) of the genotypic value for each clone were obtained across environments and regressed on order of release year to estimate annual genetic gains. We observed that genetic trends were mostly quadratic. On average, cassava mosaic disease (CMD) resistance increased by 1.9% per year, while annual genetic improvements in harvest index (0.0%) and fresh root yield (5 kg per ha or 0.03% per ha) were non-substantial. For cassava brown streak disease (CBSD) resistance breeding which was only initiated in 2003, average annual genetic gains for CBSD foliar and CBSD root necrosis resistances were 2.3% and 1.5%, respectively. It’s evident that cassava breeding has largely focused on protecting yield against diseases. This underpins the need for simultaneous improvement of cassava for disease resistance and high yield for the crop to meet its current and futuristic demands for food and industry.Item Genetic Variation Among Tropical Maize Inbred Lines from NARS and CGIAR Breeding Programs(Plant Molecular Biology Reporter, 2022) Bigirwa Ayesiga, Stella; Rubaihayo, Patrick; Oloka, Bonny Michael; Onziga Dramadri, Isaac; Edema, Richard; Sserumaga, Julius PytonThe use of molecular markers allows for precise estimates of genetic diversity, which is an important parameter that enables breeders to select parental lines and designing breeding systems. We assessed the level of genetic diversity and population structure in a panel of 151 tropical maize inbred lines using 10,940 SNP (single nucleotide polymorphism) markers generated through the DArTseq genotyping platform. The average gene diversity was 0.39 with expected heterozygosity ranging from 0.00 to 0.84, and a mean of 0.02. Analysis of molecular variance showed that 97% of allelic diversity was attributed to individual inbred lines within the populations while only 3% was distributed among the populations. Both neighbor-joining clustering and STRU CTU RE analysis classified the inbred lines into four major groups. The crosses that involve inbred lines from most divergent subgroups are expected to generate maximum heterosis and produce wide variation. The results will be beneficial for breeders to better understand and exploit the genetic diversity available in the set of maize inbred lines we studied.Item Genotype by Environment Interaction in Sesame (Sesamum indicum L.) Cultivars in Uganda(African Journal of Plant Science, 2016-10-31) Okello-Anyanga, Walter; Rubaihayo, Patrick; Paul, Gibson; Okori, PatrickSesame (Sesamum indicum L.) is an important and ancient oilseed crop cultivated in hot, dry climates for its oil and protein rich seeds. On the African continent, Uganda ranks seventh in sesame production. The improvement of new genotypes with the desired yield stability and performance in different environments is an important issue in breeding programs. In order to identify high yielding and stable sesame genotypes across environments, field experiments were conducted with 16 genotypes for four seasons (2011-2013) at three locations, viz. Serere, Kaberamaido and Ngetta. The objective of the study was to use additive main effects and multiplicative interaction (AMMI) and genotype by genotype environment interaction (GGE) biplot statistical analysis to identify the stability and yield potential of sixteen sesame genotypes. The results of AMMI analysis of variance for seed yield (kg/ha) showed that all the sources of variations that included treatments, genotypes, environments, blocks, interactions, IPCA1 and IPCA 2 were highly significant (P<0.001). The combined analysis of variance indicated that season, season x location, genotype and location x genotype had highly significant (P<0.001) variation. The GGE biplot suggested the existence of only one sesame mega-environment with genotype G9 (Local 158-1) best adapted in that mega-environment followed by G1 (Ajimo A1-6//7029)-1-1. The mega-environment had environments K2011B, K2012A, K2012B, N2012B and K2013B. The vertex genotypes which indicated that they were the most responsive in their respective environments were G2 (Ajimo A1-6//7029)-1-9, G3 (Local 158//6022)-1-2-1, G8 (EM15-3-2), G9 (Local 158-1), G12 (Renner 1-3-1-16) and G14 (Renner 1-3-1-17-1). Genotypes G2 and G12 performed poorly in poor environments. Genotypes were categorized into stable and high yielding, stable but poor yielding, unstable but good yielding and unstable and poor yielding. Environment K2013B was the most discriminating environment. According to the ideal-genotype biplot, genotype G9 (Local 158-1) was the best performing genotype and Kaberamaido was the nearest to ideal environment. It was officially released as Sesim 3 variety for commercial production because of its yield, stability, tolerance to pests and high oil content.Item Identification and mapping of quantitative trait loci associated with soybean rust (Phakopsora pachyrhizi) resistance in genotype UG 5(African Journal of Biotechnology, 2018) Gebremedhn, Hailay Mehari; Msiska, Ulemu Mercy; Weldekidan, Miesho Belay; Abate Asmamaw, Fentaw; Winnifred, Akech; Onziga, Dramadri Isaac; Lapaka Odong, Thomas; Rubaihayo, Patrick; Tukamuhabwa, PhinehasSoybean rust, Phakopsora pachyrhizi, is one of the most serious and widespread foliar diseases of soybean causing high yield losses world-wide. The objective of this study was to identify and map quantitative trait loci (QTLs) resistant to soybean rust in genotype UG 5. Ninety-seven F2 mapping plants, obtained from a cross between Wondersoya and UG 5, were used for this study. Quantitative trait locus analysis using QTL IciMapping software identified three putative QTLs associated with soybean rust (SBR) on chromosomes 6, 9 and 18 with logarithms of odds (LOD) scores ranging from 3.47 to 8.23 and phenotypic variance explained by the QTLs ranging from 18.3 to 25.6%. The putative QTL detected on chromosome 9 is novel and has not been reported elsewhere. The putative QTLs identified in this study could help to facilitate SBR resistance breeding towards efficient marker assisted selection approach and gene pyramiding leading to the development of durable resistance.Item Identification of candidate genes associated with resistance to bruchid (Callosobruchus maculatus) in cowpea(Plant Breeding, 2019) Miesho, Belay; Hailay, Mehari; Msiska, Ulemu; Bruno, Awio; Malinga, Geoffrey M.; Obia Ongom, Patrick; Edema, Richard; Gibson, Paul; Rubaihayo, Patrick; Kyamanywa, SamuelCowpea is an important legume crop widely grown in sub‐Saharan Africa for food and feed. However, it is largely challenged by bruchid, a serious storage pest resulting in losses in quantity and quality of grains. Therefore, this research was designed to contribute to the breeding of cowpea resistance to bruchid through the identification of candidate genes associated with resistance to bruchid. A total of 217 mini‐core cowpea accessions were genotyped and phenotyped for their reactions to bruchid. To determine the genomic regions linked with bruchid resistance, 41,948 polymorphic SNP markers were used. Genome‐wide association study identified 11 SNPs linked to the average number of eggs, holes, insect emergence and development period and Dobie susceptibility index. Gene search via Phytozome identified six candidate genes (Vigun08g132300, Vigun08g158000, Vigun06g053700, Vigun02g131000, Vigun01g234900 and Vigun01g201900) associated with the resistance traits. These candidate genes could be incorporated into the farmers preferred but susceptible cowpea varieties to bruchid. The SNP markers associated with the resistance traits can be used in marker‐assisted breeding for accurate and rapid screening of cowpea resistant genotypes to bruchid.Item Identification of candidate genes associated with resistance to bruchid (Callosobruchus maculatus) in cowpea(Plant Breeding, 2019-05-16) Miesho, Belay; Malinga, Geoffrey M.; Ongom, Patrick Obia; Rubaihayo, Patrick; Kyamanywa, SamuelCowpea is an important legume crop widely grown in sub-Saharan Africa for food and feed. However, it is largely challenged by bruchid, a serious storage pest resulting in losses in quantity and quality of grains. Therefore, this research was designed to contribute to the breeding of cowpea resistance to bruchid through the identification of candidate genes associated with resistance to bruchid. A total of 217 mini-core cowpea accessions were genotyped and phenotyped for their reactions to bruchid. To determine the genomic regions linked with bruchid resistance, 41,948 polymorphic SNP markers were used. Genome-wide association study identified 11 SNPs linked to the average number of eggs, holes, insect emergence and development period and Dobie susceptibility index. Gene search via Phytozome identified six candidate genes (Vigun08g132300, Vigun08g158000, Vigun06g053700, Vigun02g131000, Vigun01g234900 and Vigun01g201900) associated with the resistance traits. These candidate genes could be incorporated into the farmers preferred but susceptible cowpea varieties to bruchid. The SNP markers associated with the resistance traits can be used in marker-assisted breeding for accurate and rapid screening of cowpea resistant genotypes to bruchid.Item Influence of environment on soybean [Glycine max (L.) Merr.] resistance to groundnut leaf miner, Aproaerema modicella (Deventer) in Uganda(Journal of Plant Breeding and Crop Science, 2018) Pembele Ibanda, Angele; Karungi, Jeninah; Malinga, Geoffrey Maxwell; Adjumati Tanzito, Georges; Ocan, David; Badji, Arfang; Mwila, Natasha; Lapaka Odong, Thomas; Tukamuhabwa, Phinehas; Rubaihayo, PatrickGroundnut leaf miner (GLM) [Aproaerema modicella (Deventer)] is a serious problem for soybean cultivation in Uganda causing yield losses of up to 100%. The use of soybean [Glycine max (L.) Merr.] cultivars resistant to GLM attack is an important strategy in the integrated pest management program. The aim of this study was to determine the environment × genotype interaction influence on the soybean resistance traits to GLM attack. Eighteen soybean genotypes were evaluated for resistance to GLM attack. The experiment was set up using randomized complete block design replicated three times under natural pest infestation in Budaka (Eastern) and Arua (Northern) districts in Uganda. Data were subjected to analysis of variance, Pearson’s phenotypic correlation and cluster analysis. Highly significant (p < 0.001) differences among the genotypes were recorded for all the studied traits, except the number of pupae per plant which was significant (p < 0.05). GLM incidence and severity had significant negative correlations with rainfall and relative humidity. However, there were significant positive correlations between minimum temperature and GLM incidence as well as severity for most of the genotypes. Soybean genotypes VI046160 and VI046167 could be used as parents in breeding for resistance to GLM pest. Areas with high rainfall and humidity would be recommended for soybean production to minimize infestation by GLM.Item Influence of environment on soybean [Glycine max (L.) Merr.] resistance to groundnut leaf miner, Aproaerema modicella (Deventer) in Uganda(Journal of Plant Breeding and Crop Science, 2018) Pembele Ibanda, Angele; Karungi, Jeninah; Malinga, Geoffrey Maxwell; Adjumati Tanzito, Georges; Ocan, David; Badji, Arfang; Mwila, Natasha; Lapaka Odong, Thomas; Tukamuhabwa, Phinehas; Rubaihayo, PatrickGroundnut leaf miner (GLM) [Aproaerema modicella (Deventer)] is a serious problem for soybean cultivation in Uganda causing yield losses of up to 100%. The use of soybean [Glycine max (L.) Merr.] cultivars resistant to GLM attack is an important strategy in the integrated pest management program. The aim of this study was to determine the environment × genotype interaction influence on the soybean resistance traits to GLM attack. Eighteen soybean genotypes were evaluated for resistance to GLM attack. The experiment was set up using randomized complete block design replicated three times under natural pest infestation in Budaka (Eastern) and Arua (Northern) districts in Uganda. Data were subjected to analysis of variance, Pearson’s phenotypic correlation and cluster analysis. Highly significant (p < 0.001) differences among the genotypes were recorded for all the studied traits, except the number of pupae per plant which was significant (p < 0.05). GLM incidence and severity had significant negative correlations with rainfall and relative humidity. However, there were significant positive correlations between minimum temperature and GLM incidence as well as severity for most of the genotypes. Soybean genotypes VI046160 and VI046167 could be used as parents in breeding for resistance to GLM pest. Areas with high rainfall and humidity would be recommended for soybean production to minimize infestation by GLM.Item Inheritance of soybean resistance to soybean rust in Uganda’s soybean germplasm(International Journal of Agronomy and Agricultural Research, 2018) Gebremedhn, Hailay Mehari; Belay Weldekidan, Miesho; Msiska, Ulemu Mercy; Asmamaw, Fentaw Abate; Lapaka Odong, Thomas; Tukamuhabwa, Phinehas; Rubaihayo, PatrickUnderstanding the genetic mechanisms of soybean rust resistance is important for effective selection and breeding procedures. This study was hence conducted to determine the combining ability and gene action controlling soybean rust using a 10x10 half diallel mating design. The F2 segregating populations along with their parents were evaluated for rust severity and sporulation level at two reproductive stages (R4 and R6) in screen house and field conditions during the second season of 2016 and first season of 2017 at MUARIK using an alpha lattice design replicated thrice. Significant differences were observed among the parents and F2 generations for both disease severity and sporulation level. General and specific combining abilities were highly significant. The GCA/SCA ratio (1.50-2.30) and the Baker’s ratio (0.75-0.82) showed the predominance of additive gene action in the inheritance of soybean rust resistance. The broad-sense (0.94-0.99) and narrow-sense (0.73-0.82) heritability estimates indicated the possibility of improving resistance to soybean rust through selection in the early generations. UG 5, Maksoy 3N, Maksoy 4N and Maksoy 5N had negative GCA effects. The F2 populations derived from these parents crossed with Wonder soya and Nam 2 had also negative SCA effects. The use of these parents and F2 populations can, therefore, increase the response to selection for improving resistance to soybean rust.Item Maize Combined Insect Resistance Genomic Regions and Their Co-localization With Cell Wall Constituents Revealed by Tissue-Specific QTL Meta-Analyses(Plant Science, 2018) Badji, Arfang; Otim, Michael; Machida, Lewis; Odong, Thomas; Bomet Kwemoi, Daniel; Okii, Dennis; Agbahoungba, Symphorien; Mwila, Natasha; Kumi, Frank; Ibanda, Angele; Mugo, Stephen; Kyamanywa, Samuel; Rubaihayo, PatrickCombinatorial insect attacks on maize leaves, stems, and kernels cause significant yield losses and mycotoxin contaminations. Several small effect quantitative trait loci (QTL) control maize resistance to stem borers and storage pests and are correlated withsecondary metabolites. However, efficient use of QTL in molecular breeding requires a synthesis of the available resistance information. In this study, separate meta-analyses of QTL of maize response to stem borers and storage pests feeding on leaves, stems, and kernels along with maize cell wall constituents discovered in these tissues generated 24 leaf (LIR), 42 stem (SIR), and 20 kernel (KIR) insect resistance meta-QTL (MQTL) of a diverse genetic and geographical background. Most of these MQTL involved resistance to several insect species, therefore, generating a significant interest for multiple-insect resistance breeding. Some of the LIR MQTL such as LIR4, 17, and 22 involve resistance to European corn borer, sugarcane borer, and southwestern corn borer.Item Mode of inheritance for resistance to FOC Race 1 and fruit quality traits in Sukali Ndizi cultivar of Banana(Journal of Plant Breeding and Crop Science, 2021) Buregyeya, Henry; Tumwesigye, Kashub S.; Matovu, Moses; Nowakunda, Kephas; Namanya, Priver; Tushemereirwe, Wilberforce K.; Karamura, Eldad; Rubaihayo, PatrickInformation on the genetic control of resistance to Fusarium oxysporum f.sp.cubense (FOC) race (1) and fruit quality traits in Sukali Ndizi cultivar of banana is key to its genetic improvement. The mode of resistance to Fusarium wilt in Sukali Ndizi was analyzed in 536 hybrids and 5 parental lines and quality attributes in 137 hybrids and two parental lines, grown in same environment. Fruit quality was assessed by physical measurements and fruit composition whereas resistance to Fusarium wilt was assessed by corm discoloration symptoms. All the assessed traits were quantitatively inherited. Flavor attributes, and pulp texture showed a predominance of additive inheritance with complementary gene action whereas total soluble solutes showed non-additive gene with dominant gene action. Fruit acidity had incomplete dominancy with the genetic model explained by both single gene and certain multiple genes. Resistance to Fusarium wilt showed dominant gene action and polygenic effects. Involvement of a few genes governing wilt resistance suggested the ease of breeding for this trait. Pedigree breeding method could be recommended for incorporating various traits in (cv. Sukali Ndizi) of banana.Item Mode of inheritance for resistance to FOC Race 1 and fruit quality traits in Sukali Ndizi cultivar of Banana(Journal of Plant Breeding and Crop Science, 2021-10-31) Buregyeya, Henry; Tumwesigye, Kashub S.; Namanya, Priver; Karamura, Eldad; Rubaihayo, PatrickInformation on the genetic control of resistance to Fusarium oxysporum f.sp.cubense (FOC) race (1) and fruit quality traits in Sukali Ndizi cultivar of banana is key to its genetic improvement. The mode of resistance to Fusarium wilt in Sukali Ndizi was analyzed in 536 hybrids and 5 parental lines and quality attributes in 137 hybrids and two parental lines, grown in same environment. Fruit quality was assessed by physical measurements and fruit composition whereas resistance to Fusarium wilt was assessed by corm discoloration symptoms. All the assessed traits were quantitatively inherited. Flavor attributes, and pulp texture showed a predominance of additive inheritance with complementary gene action whereas total soluble solutes showed non-additive gene with dominant gene action. Fruit acidity had incomplete dominancy with the genetic model explained by both single gene and certain multiple genes. Resistance to Fusarium wilt showed dominant gene action and polygenic effects. Involvement of a few genes governing wilt resistance suggested the ease of breeding for this trait. Pedigree breeding method could be recommended for incorporating various traits in (cv. Sukali Ndizi) of banana.