National Semi-Arid Resources Research Research Articles

Effect of Potassium Nitrate Spray on the Flowering and Fruiting of Mango Varieties Grown in Uganda

Aims: To evaluate the effect of potassium nitrate (KNO3) on flowering and fruiting of mangoes in Uganda.
 Study Design: Randomized complete block design in a split plot arrangement.
 Place and Duration of Study: National Crops Resources Research Institute Namulonge, National Semi–Arid Resources Research Institute in Serere and Bulindi Zonal Agricultural Research and Development Institute in Hoima in 2015 and 2016.
 Methodology: The study was superimposed on eight-year-old mango orchards which were simultaneously planted at the three sites. Main plot treatments comprised three mango varieties (Bire, Tommy Atkins, Zillate), while sub-plot treatments comprised four concentrations of KNO3 (zero as control, 1, 2 and 4%). Data was collected on number of terminal buds induced after applying KNO3, percentage flowering, number of fruits set per 20 panicles and fruit yield per tree.
 Results: Trees sprayed with KNO3 produced higher (P < .05) numbers of terminal buds than the control. Across sites, Bire produced higher numbers of buds (64.8) than Tommy Atkins (46.3) and Zillate (17.8). Flowering response was higher in Bire (28.6%) than in Tommy Atkins (20.8%) and Zillate (17.8%). Flowering response of trees sprayed with 2% KNO3 (31.4%) was higher than that of trees sprayed with 1% KNO3 (24.7%). Mean number of fruits induced per 20 panicles in trees sprayed with 4% KNO3 (8.24) was higher than that of trees sprayed with 1% KNO3 (4.8). Fruit yield of Tommy Atkins (23.01 kg/tree) was higher than that of Bire (10.97 kg/tree). Mean fruit yield of trees sprayed with 2% KNO3 (27.36 kg/tree) was higher than that of trees sprayed with 1% KNO3 (15.93 kg/tree).
 Conclusion: For better fruit yields, farmers at Bulindi should grow Tommy Atkins and apply 2% KNO3. Farmers at Namulonge can grow any of the three mango varieties and apply 2 or 4% KNO3, while those at Serere can grow Tommy Atkins and Zillate, and should apply 4% KNO3.

Registration of ‘NAROSORG1 and NAROSORG3’ Sorghum Varieties with High Grain Yield and Superior Grain Qualities from Uganda

Sorghum [<i>Sorghum bicolor</i> (L.) Moench] is the third most important cereals after maize and rice in Uganda. It is mainly grown by the resource-poor rural farmers in Uganda as a staple food, but this trend has changed recently due to the gradual transition of the crop from traditional food crops to a cash crop. National Semi-Arid Resources Research Institute (NaSARRI) therefore developed and released NAROSORG1 and NAROSORG3 in 2017 with high yields and superior grain qualities for food and commercial beer production in the country. NAROSORG1 and NAROSORG3 are a selection from the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) advanced breeding lines ICSR160 and IESV92043DL respectively. Sorghum line, IESV92043DL (NAROSORG3) was bred by ICRISAT Nairobi from a cross between KARI Mtama 1 x Seredo and developed into an open-pollinated pure line variety through pedigree selection. However, the sorghum line, ICSR160 (NAROSORG1) was introduced as a Restorer or Male Parent (R-Line) for hybrid development from ICRISAT India but adapted well as a variety with very good brewing qualities for lager beer (no tannin and high extracts) production and its white-seeded variety. Performance evaluation was conducted in Uganda for two consecutive seasons of 2017 and the results showed that NAROSORG1 and NAROSORG3 had significantly higher grain yields (13.8% and 12.2%) and 1000-seed weight percentages (30.2% and 28.9%) respectively than commercial check variety, SESO1. NAROSORG1 has a good grain quality with 100% free tannin levels which is good for commercial lager beer production while NAROSORG3 had sweet juicy stalk with stay-green trait suitable for forage production in addition to good grain quality.

Gene action governing the inheritance of drought tolerance and selected agronomic traits in Ugandan groundnut (Arachis hypogaea L.) lines under drought environment

Breeding drought tolerance in groundnuts cultivars would reduce yield losses due to drought stress in rain-fed growing areas. The mode of gene action governing the inheritance of drought tolerance and secondary traits was investigated by mating 30 lines according to North Carolina design II scheme. The parents and resulting 75 F2 progenies were grown in a split plot arrangement using an alpha lattice design, with two replications under drought and non-stressed environments for two seasons. The trials were conducted over two seasons, in 2017 A and 2017 B at the National Semi-Arid Resources Research Institute, located 27 km west of Soroti town in eastern Uganda. The results showed highly significant differences between families and parents for drought tolerance and agronomic traits. Traits including BIO, DTI(PY), DTI (BIO) and HI had the highest correlations with PY. HI was positively associated with no. of pods per plant under drought stressed and non-stressed environments. Under drought stressed environment, GCA was more important than SCA for traits such as SCMR2, and HI. However, SCA was more important than GCA for traits such as SCMR2, PY, BIO, DTI(PY), and DTI (BIO). The study identified parents with best GCA and combinations with best SCA effects for both agronomic and drought tolerance traits. The new population is shown to be a valuable genetic resource for variety selection and improvement of groundnut for adaptation to the drought prone areas of Uganda.

Potential for yield loss reduction and profitability assessment of pesticide control of groundnut leaf miner among soybean genotypes

Groundnut leaf miner (GLM) is currently a threat to soybean production in Uganda due to the great yield losses as a result of the severe damage it causes on leaves leading to reduced photosynthetic area. GLM is a fairly new pest on soybean in Uganda, having initially been observed in soybean fields in 2011 in eastern Uganda. The objective of this study was to determine the yield loss caused by the groundnut leaf miner and effectiveness and profitability of commonly used pesticides for the control of the groundnut leaf miner (Aproaerema modicella Deventer) (GLM), when tested with popular soybean (Glycine max) genotypes grown in Uganda. In a split plot RCBD design, pesticide protection (treated vs. untreated) formed the main plots; and six commercial soybean varieties (Maksoy 1N, 2N, 3N, 4N, 5N; and Namsoy 4M) as subplots. The study was done in two locations in eastern Uganda (Iki Iki District Agricultural Training and Information Centre (Iki Iki DATIC) and National Semi-Arid Resources Research Institute, Serere (NaSARRI) with two planting rounds at Iki Iki. These sites were chosen because they are hot spots for GLM. GLM severity and soybean yield were significantly affected by the pesticide protection. Overall, percentage grain yield losses caused by GLM on the different soybean varieties ranged from 37.3% to 65.7% and the highest loss was displayed by Maksoy 5N. Grain yield loss recorded at Iki Iki DATIC (53.1%) was remarkably higher than that recorded at the NaSARRI (49.1%). Economic analysis showed marginal returns to be dependent on location, with the Iki Iki DATIC having 0.6 and NaSARRI 1.1. This study has shown that the groundnut leaf miner, a recently emergent pest of soybean is becoming a big threat to soybean production and that chemical control alone may not be economical in managing the pest.Key words: Aproaerema modicella, Glycine max, marginal returns, Uganda

Performance and inheritance of yield and maize streak virus disease resistance in white maize and yellow conversions

In sub Saharan Africa, past effort has registered success in developing high yielding and foliar disease resistant maize (Zea mays L.) varieties, which are deficient in pro-vitamin A. A new initiative is to develop maize varieties, tolerant to foliar diseases and rich in pro-vitamin A carotenoids. To achieve this, yellow conversions of white testers and other elite maize varieties have been developed by the International Center for Maize and Wheat Development (CIMMYT). Unlike the white lines, limited information on agronomic performance and disease resistance is available for yellow maize conversions. This study was conducted to evaluate the performance of white maize and their corresponding yellow maize conversions for yield and tolerance to Maize streak virus (MSV) disease; and determine the inheritance patterns of these traits. Fourty seven three-way hybrids generated in a Line by tester mating design (North Carolina 2), 12 inbred lines (used as male parents), 4 single crosses (used as female parents) and 3 commercials checks were screened for resistance to Maize streak virus (MSV) disease at the National Crop Resources Research Institute (NaCRRI) in Uganda. The same genotypes were evaluated in a 9x5 alpha lattice design in three locations of Uganda (National Crop Resources Research Institute (NACRRI), National Semi Arid Resources Research Institute (NaSARRI) and Bulambuli) for agronomic performance. Results confirmed tolerance to MSV in testers CML202, CML395, CML444, CML445 and CML312-SR (white). Genotypes performed significantly differently for yield, anthesis days, plant height, ear height, husk cover, grain texture, reaction to Gray leaf spot (GLS) (P&lt;0.001) and ear aspect (P&lt;0.01). However, pairwise comparison of white and yellow conversions indicated no significant difference (P&gt;0.05) in agronomic performance and tolerance to diseases. General combining ability (GCA) was more important than specific combining ability (SCA) for most traits, except for anthesis days, Turcicum leaf blight (TLB), GLS and yield. GCA effects for yield were not significant in both lines (male parents) and single cross testers (female parents) of white and yellow conversions. However, two unique cases were observed for diseases; yellow conversion of line CML444 significantly combined for susceptibility to TLB; while tester CML312/CML442 combined for resistance to GLS. Additionally, there was low heritably estimates for tolerance to MSV and yield. Generally, there was no significant difference between white and corresponding yellow maize conversion, implying that there is no significant loss in MSV resistance and yield performance while converting white into yellow maize.Key words: Combining ability, pro-vitamin A, Zea mays L.

Virus Movement from Infected Sweetpotato Vines to Roots and Reversion on Root Sprouts

Sweetpotato is usually propagated in Uganda by vine cuttings from mature crops, but sometimes sprouts from storage roots are used, especially in drought-prone areas. No information is available on whether the storage of roots of Ugandan cultivars are infected with the viruses and whether the sprouts on them express symptoms so that farmers can eliminate diseased ones. Information on root sprout reversion from virus infection is also lacking. The storage roots of five sweetpotato cultivars was sourced either by random selection of roots from already harvested roots or obtained from symptomless plants selected before harvest at Makerere University Agricultural Research Institute, Kabanyolo (MUARIK), and the National Semi Arid Resources Research Institute (NaSARRI). Roots were also generated in a screenhouse after being inoculated with Sweet potato feathery mottle virus (SPFMV) and/or Sweet potato chlorotic stunt virus (SPCSV). More than 70% of sprouts from roots of all the cultivars selected after harvest at MUARIK and NaSARRI were infected with the viruses. For roots obtained from symptomless plants, 64% and 21% of the sprouted roots from MUARIK and NaSARRI were infected with the viruses, respectively. Most of the root samples from MUARIK had visible virus symptoms on sprouts and tested positive for both SPFMV and SPCSV, whereas those from NaSARRI did not show symptoms and were infected primarily with SPFMV. Plants graft-inoculated with either SPCSV or SPFMV alone produced both infected and noninfected roots, whereas all the root sprouts from dually infected plants showed virus symptoms. Reversion from virus infection was observed on root sprouts infected singly with SPFMV, whereas those infected with SPCSV showed recovery only, and none of the root sprouts infected by both viruses showed recovery. This study proves that roots are good reservoirs for viruses, and reversion occurs only when singly infected with SPFMV. Therefore, there is a need to establish seed channels in which seedstock is cleaned continuously and made available to farmers.

English

Groundnuts (Arachis hypogaea L.) are the second most important legume crops after beans, an important source of protein (23 to 25%), fats/oils (40 to 52%) and carbohydrates (10 to 20 %) and widely grown and consumed in Uganda including the Lake Albert Crescent Zone (LACZ). Due to susceptibility of local varieties to groundnut rosette, National Agricultural Research Organisation (NARO) through the National Semi Arid Resources Research Institute (NaSARRI) developed and released the serenut varieties. Adaptive trials were therefore established in the LACZ, to select the most location specific adapted varieties for promotion in this ecologically diverse zone. Four serenut varieties namely serenut 5, 8, 10 and 14 and a locally grown variety (Red beauty) were planted on three farmers’ fields in each of the three sub-ecological areas. Data were collected on total pod dry weight (yield), number of pods and on 100 seed weight. In this study, we show that overall yields of serenut 5, serenut 14, serenut 8 and serenut 10 were highly significantly (P < 0.001) different for all traits measured across the sub-ecological areas. Best yields were recorded from the humid tropical rain forest sub-ecological area where 1900 kg/ha were obtained for serenut 14, 2366 kg/ha for serenut 10, 1763 kg/ha for serenut 8 and 1795 kg/ha for serenut 5. The yields obtained from these varieties were generally worst in the semi-arid sub-ecological area. These serenut varieties are generally adapted to wider environmental conditions although their performance per se was found to be generally inconsistent. This study has also found that among all the varieties tested, Serenut 5 was the best adapted across all the sub-ecologies. Overall, we therefore recommend farmers in this ecologically diverse zone to grow these groundnut varieties with improved growing practices such as timely planting, timely weeding, earthing up and pest and disease management in order to obtain consistent high yields. Key words: Groundnut, performance, stability, sub-ecological area.

Assessment of Groundnut (Arachis hypogaea L.) Genotypes for Yield and Resistance to Late Leaf Spot and Rosette Diseases

Groundnut which is a major staple food crop in Uganda is constrained by late leaf spot (LLS) and groundnut rosette disease (GRD), accounting for major economic yield loss. This study was conducted to identify sources of resistance to LLS and GRD and yield potential of selected groundnut genotypes that could be used in breeding programs. Thirty-eight groundnut genotypes were evaluated at the National Semi Arid Resources Research Institute (NaSARRI)-Serere, EasternUganda during the first and second seasons of 2015. The experiment was arranged in randomized complete block design with four replications. The results showed highly significant (P < 0.01) genotype-by-season interaction for most of the traits studied. There were significant differences among the genotypes for 100 seed weight (P < 0.01), and dry pod yield and unshelled sample of 100 pods at P < 0.05. Late leaf spot severity (at harvest), GRD incidence (at 12 weeks) and severity (at harvest) were significantly (P < .01) different and positively correlated with Area Under Disease Progress Curve (AUDPC). GRD severity at harvest showed highly significant (P < 0.001) negative correlation with shelling percentage. Both 100 seed weight and unshelled sample of 100 pod showed highly significant (P < 0.01) negative correlations with LLS at harvest, LLS AUDPC, GRD at 12 weeks, GRD AUDPC, and GRD severity. Genotypes susceptible to both LLS and GRD recorded the lowest 100 seed weight. Nine genotypes (Serenut.2, SGV 0001, SGV 0005, SGV 0006, SGV 0019, SGV 0071, SGV 0082, SGV 0083, and SGV 89751T) showed resistance to both diseases with high yield potential. These genotypes could be used to introgress resistance to both diseases in acceptable cultivars which are susceptible.

Towards the Selection of Superior Sesame Lines Based on Genetic and Phenotypic Characterisation for Uganda

Understanding agricultural biodiversity is critical to formulate breeding strategies for crop improvement and it impacts both, conservation and collection activities. Especially germplasm collections serve as valuable resources, thus, their adequate characterisation is of utmost importance. Although Uganda ranks seventh in African sesame production, meagre research was conducted to determine the current genetic diversity among its germplasm. Therefore, in the present study part of the sesame germplasm conserved at the National Semi-Arid Resources Research Institute (NaSARRI) in Uganda focusing on 85 established lines was genetically and phenotypically characterised. Population genetic and structure analyses revealed rather a low extend of genetic diversity (expected heterozygosity [HE], or gene diversity [D]) ranging from 0 to 0.38 per entry, but a high extend of admixture within and between entries. This decrease of heterozygosity is supported by a fixation index (FST) of 0.530, indicating a medium genetic differentiation among entries. The analysis of quantitative and qualitative agromorphological traits revealed a great inter-trait variability among the entries and further indicated a certain conservation of some of the traits reflecting the geographic origin of the analysed entries. Based on both, the genetic and phenotypic characterisation, a selection of 26 superior entries is proposed, which may form a valuable basis both for farmers and breeders.

Effects of Organic Residues on Soil Properties and Sesame Water Use Efficiency

A study was conducted at the National Semi-Arid Resources Research Institute-Serere, Uganda for three seasons (2013 short rains, 2014 long rains and 2014 short rains) to investigate the effect of crop residues and animal manure on soil bulk density (SBD), soil moisture content (SMC) and water use efficiency (WUE) of sesame. The experiment was laid out in a randomized complete block design with three replications. The treatments comprised: control, 4 crop residues, 2 animal manures and combinations of 2 animal manures and 4 crop residues all applied at two rates of 3 and 6 t/ha. Plots treated with 6 t/ha of millet husks produced the highest SMC (37.46%) and lowest SBD (1.1717 g/cm3) across seasons; while plots treated with 3 t/ha of millet husks produced the highest WUE of sesame (9.92 kg ha-1 mm-1) across seasons compared with other crop residue and animal manure treatments applied singly. Soil moisture content was highest (38.09%) and SBD lowest (1.0520 g/cm3) across seasons in plots treated with 6 t/ha of poultry manure plus millet husks; while plots amended with 3 t/ha of poultry manure plus millet husks produced the highest WUE of sesame (9.40 g/cm3) across seasons compared with other treatments. Crop residues influenced SMC and SBD in the order; millet husks &gt; cowpea husks &gt; sorghum husks &gt; groundnut shells. Crop residues affected WUE of sesame in the order; millet husks &gt; sorghum husks &gt; groundnut shells &gt; cowpea husks. This study has demonstrated that poultry manure plus millet husks have a potential to enhance WUE of sesame.

Decomposition and Nutrient Release of Selected Cereal and Legume Crop Residues

Crop residues have the potential to enhance soil fertility, but this is dependent on their biochemical quality. A study was conducted at the National Semi-Arid Resources Research Institute-Serere, Uganda to determine the chemical composition, nutrient release patterns and rates of selected crop residues. The design used was randomized complete block design with four replications. The treatments comprised of 20g of finger millet, sorghum, cowpea and groundnut crop residues. Finger millet had the highest initial C (36.28%) and N (3.46%), cowpea had the highest initial P (0.60%) and Ca (0.30%) and groundnut shells had significantly the highest initial K (1.01%). Finger millet husks with the lowest carbon/nitrogen ratio, had significantly the highest rate of dry matter disappearance and nutrient release, while groundnut shells with the highest carbon/nitrogen and carbon/phosphorus ratios had significantly the lowest nutrient release and dry matter disappearance rates. At the end of incubation, finger millet husks had significantly the lowest N (0.29%) and C (10.22%), while cowpea husks had the lowest P (0.27%), K (0.18%) and Ca (0.27%). Nutrient release and dry matter disappearance rates of crop residues occurred in the order of N &gt; K &gt; P &gt; Ca and finger millet husks &gt; cowpea husks &gt; sorghum husks &gt; groundnut shells, respectively. This study has demonstrated that finger millet husks released nutrients faster and this is beneficial for early planted crops, while groundnut shells released nutrients slowly which is appropriate for long term availability of plant nutrients.

Efficacy of bio and synthetic pesticides against the American bollworm and their natural enemies on cotton

Cotton production in Uganda is limited by various factors among which insects pests are the most important. The key insect pests of cotton are the bollworm complex; spotted bollworm, Earias insulana ; pink bollworm, Pectinophora gossypiella and American bollworm, Helicoverpa armigera . The American bollworm is an alien species and the most disastrous among all the three bollworm species attacking cotton in Uganda. Management for the bollworm complex in Uganda is largely synthetic chemical use with little or no biopesticide use which reduces natural enemies population and resistance development to continuous use of a single synthetic pesticide product. Therefore this study aimed at determining the efficacy of bio and synthetic pesticides on the management of cotton bollworm pests with special reference to the American bollworm. The pesticides in the study included Nimbecidine (Azaradactin), Engeo K247SC (Lambda Cyhalothrin 106 g l -1 + Thiamethoxam 141 g l -1 ), Talstar (Bifenthrin), and Amdoc3EC (Emamectin and Abamectin), Aster extreme 20SL (Acetamiprid 150g/l and Cypermethrin 50 g l -1 ), Agrolambacin (15 g l -1 Lambda Cyhalothrin + 300 g l -1 Profenofos), Thiodicarb (Larvin 80DF), and Methomyl (Lannate 40SP) on cotton bollworm ( Helicoverpa amigera ) and its natural enemies in eastern Uganda. The study was conducted at the National Semi-Arid Resources Research Institute (NaSARRI) under both laboratory and field conditions. Under laboratory controlled conditions, recommended doses of these bio and synthetic pesticides were used against third instar larvae of the American bollworm in a completely randomised experimental design with five replicates. Amdoc 3EC and Nimbecidine, showed maximum efficacy, 100 %, in terms of mortality after 72 hours. While Engeo, Aster extreme and Agrolambacin showed maximum mortality of (100%) after 96 hours followed by Larvin 80DF (80%) and Lannate 40SP (67%). In the field conditions, Nimbecidine (0.3 and 1.00) and Talstar (2.0 and 1.7) were the most effective bio-pesticides; while Amdoc with means (1.8 and 1.9), Aster extreme (2.0 and 1.8) and Agrolambacin (1.5 and 1.3) were the most effective synthetic pesticides respectively. Seed cotton yield was significantly higher in biopesticide treated plots, Talstar 1966 , 1935 kg ha -1 , Nimbicidine 1985 and 1715 kg ha -1 compared to the synthetic pesticide treated plots with amdoc1935 and 1506 , Agrolambacin 1846 and 1722 kg ha -1 , Aster extreme 1733 and 1930 kg ha -1 respectively. Computation of the benefit cost ratios showed that these new chemical pesticides were all financially viable and, therefore, adoptable by the cotton farmers, respectively which also performed better than the controls 1012 and 912kg ha -1 outside the experiment, 892 and 602 kg ha -1 inside the experimental area. In addition, synthetic pesticides treated plots were associated with significant reductions in natural enemies populations. In contrast biopesticide treatments had minimum side effects on the natural enemies populations. Keywords: Cotton, Helicoverpa amigera

English

An 8 x 8 diallel cross mating design with the parents and F1s was used to estimate gene action and combining ability for yield and yield characters in sesame (Sesamum indicum L.). The experiment was conducted at the National Semi-Arid Resources Research Institute (NaSARRI), Serere, Uganda during the second season of 2013. The traits involved: days to 50% flowering, days to maturity, height to first branch, height to first capsules, plant height, length of the capsule fruiting zone and yield per plant. The genetic variance of combining ability was separated into general (GCA) and specific (SCA) combining ability variance components. Baker’s ratio, coefficients of genetic determination (CGD) were determined for narrow and broad sense heritabilities. High GCA effects were recorded for days to flowering, height of first capsule and number of branches, branches per plant and capsule length. Desirable SCA effects were recorded for Sesim2//5181 x Renner 1-3-1-1 for reduced height of first branch (-9.48*), Sesim1 x Sesim2 for number of branches per plant (0.901*), capsules on branches (20.75**) and yield per plant (2.42*). High Baker’s ratio was recorded for most of the traits except for yield per plant (0.233). CGDbs was high for most of the traits except for days to maturity (0.064), plant height (0.346), capsules on main stem (0.358) and capsule width (0.286). These results suggested that both additive and non-additive gene actions played a greater role in these traits. Sesim 1 had the highest number of desirable traits scored for GCA effects and could be considered as a parent for crossing to produce desirable progeny. Sesim 1 x Sesim 2, Sesim 1 x Ajimo A1-5 and Sesim2//5181 x SPS1438-1-6-4 recorded positive significant SCA effects for yield per plant and therefore they could be recommended for hybrid seed production. Key words: Baker’s ratio, coefficient of genetic determination, gene effects, yield, yield components, sesame.

Adaptation of introduced mungbean genotypes in Uganda

Mungbean (Vigna radiata (L.) Wilczek) is an important source of nutrients and income for smallholder farmers in East Africa. Mungbean production in countries like Uganda largely depends on landraces, in the absence of improved varieties. In order to enhance productivity, efforts have been underway to develop and evaluate mungbean varieties that meet farmers’ needs in various parts of the country. This study was conducted at six locations in Uganda, to determine the adaptability of introduced mungbean genotypes, and identify mungbean production mega-environments in Uganda. Eleven genotypes (Filsan, Sunshine, Blackgram, Mauritius1, VC6148 (50-12), VC6173 (B-10),Yellowmungo, KPS1, VC6137(B-14),VC6372(45-60),VC6153(B-20P) and one local check were evaluated in six locations during 2013 and 2014. The locations were; National Semi Arid Resources Research Institute (NaSARRI), Abi Zonal Agricultural Research and Development Institute (AbiZARDI),Kaberamaido variety trial center, Kumi variety trial center, Nabuin Zonal Agricultural Research and Development Institute (NabuinZARDI), and Ngetta Zonal Agricultural Research and Development Institute (NgettaZARDI). G × E interactions were significant for grain yield. Through GGEBiplot analysis, three introduced genotypes (Filsan, Blackgram and Sunshine) were found to be stable and high yielding, and therefore, were recommended for release. The six test multi-locations were grouped into two candidate mega-environments for mungbean production (one comprising of AbiZARDI and Kaberamaido and the other comprising of NaSARRI, NabuinZARDI, Kumi, and NgettaZARDI). National Semi Arid Resources Research Institute (NaSARRI) was the most suitable environment in terms of both discriminative ability and representativeness and therefore can be used for selection of widely adaptable genotypes.Key Words: Biplot, mega-environment, Vigna radiata

Gene effects for resistance to groundnut rossette disease in exotic Valencia groundnuts

Two exotic Valencia groundnut ( Arachis hypogaea L.) breeding lines (NuMex-M 3 and Valencia C) with superior characteristics were introduced by National Legume Improvement Program at the National Semi-Arid Resources Research Institute (NaSARRI), from the United States of America, to broaden the Valencia germplasm base in Uganda. The materials were evaluated for biotic and abiotic stresses, but succumbed to groundnut rosette disease (GRD). For these superior lines to find utility in Uganda, they need further improvement by introducing resistance genes to GRD. A study was conducted at NaSARRI to determine nature of gene action controlling resistance to GRD, using the Exotic Valencia groundnut breeding materials. Six generations that included F 1 , F 2 , BC 1 P 1 and BC 1 P 2 populations, together with their parents (P 1 and P 2 ) of each of the six crosses, namely Valencia C (P 1 ) × ICGV-SM 90704 (P 2 ), Valencia C (P 1 ) × ICGV-SM 96801(P 2 ), Valencia C (P 1 ) × ICGV-SM 99566 (P 2 ), NuMex-M 3 (P 1 ) × ICGV-SM 90704 (P 2 ), NuMex-M 3 × ICGV-SM 96801 (P 2 ), and NuMex-M 3 (P 1 ) × ICGVSM 99566 (P 2 ), were evaluated for GRD resistance.The study reaveled additive and non-additive gene effects in the control of GRD resistance.Three types of epistatic gene effects, viz . additive × additive [i], additive × dominance [j] and dominance × dominance [l],were exhibited tocontrol GRD resistance. The component dominance × dominance [l] was more predominant in Valencia C × ICGV-SM 96801, NuMex-M 3 × ICGV-SM 96801, NuMex- M 3 × ICGV-SM 90704, NuMex-M 3 × ICGV-SM 99566 and Valencia C × ICGV-SM 99566 crosses. Opposite and significant signs of dominance [d] and dominance × dominance [l] components indicated the importance of duplicate epitasis in the latter crosses in the control of GRD resistance, which revealed a complex nature of inheritance of GRD resistance. Keywords: Arachis hypogaea , gene effects, GRD resistance

Evaluation of Ugandan Cowpea Germplasm for Yield and Resistance to Scab Disease

Aims: This study was conducted to identify cowpea (Vigna unguiculata) cultivars with high yield potential and resistance to scab disease caused by Sphaceloma sp. in Uganda. 100 cowpea genotypes were evaluated at two locations (Kabanyolo and Serere) in Uganda between April and July, 2014 using a 10 × 10 alpha lattice design. Place and Duration of Study: Makerere University Agriculture Research Institute Kabanyolo (MUARIK) and the National Semi Arid Resources Research Institute (NaSARRI) – Serere between April to July, 2014. Study Design and Methodology: Hundred cowpea lines (69 landraces, 25 inbred lines at F7, 1 local and 5 improved cultivars) were grown at each location in a 10 × 10 alpha lattice design with 3 replications to assess their reaction to the scab disease and yield potential (grain yield and yield related traits). Results: The cowpea lines differed significantly (P = .05) in their response to natural disease Original Research Article Afutu et al.; AJEA, 12(2): 1-18, 2016; Article no.AJEA.25138 2 pressure as determined by disease incidence, apparent infection rate (r) and severity indicated by area under disease progress curve (AUDPC). Analysis of variance showed that there was highly significant differences (P < .001) in genotypes, locations, AUDPC and other traits and genotype by location (G×L) interaction on AUDPC. The correlation analysis revealed a positive relationship of scab disease incidence with AUDPC (0.8; P < .001) but a significant (P < .001) negative relationship with grain yield (-0.8), number of pods per plant (-0.5), number of seeds per pod (-0.5) and 100 seed weight (-0.5). Cluster analysis based on only scab disease indexes produced 4 main clusters while cluster analysis based on disease and yield traits produced 3 main clusters. However, the two different clusters revealed similar grouping patterns in which cowpea lines with similar resistance ratings were shown to form unique clusters. R-mode principal component analysis yielded 4 principal components explaining 62.28% of the variation observed. Conclusion: The study revealed that the use of apparent infection rate “r” alone as an index for rating a genotype for scab reaction was not decisive. One line (NE 15) was found to be resistant to the scab disease at both locations and high yielding and could be used in the cowpea improvement programme to breed for resistance to the scab disease.

Phenotypic Diversity of Selected Dual Purpose Forage and Grain Sorghum Genotypes

Aims: To study the phenotypic diversity of 25 forage and 45 grain sorghum genotypes for dual purpose as food and feed and to identify traits that might contribute to genetic improvement. Study Design: A 7 ◊ 10 alpha lattice design was used with two replications at two sites. Place and Duration of Study: The study was conducted at Makerere University Agricultural Research Institute Kabanyolo (MUARIK) and National Semi Arid Resources Research Institute (NaSARRI) in Uganda between September to December, 2013 (Season 1) and April to July 2014 (season 2). Methodology: Morphological and agronomic data were taken for each genotype from each environment in the two seasons and subjected to combined analysis of variance separately for the grain and forage sorghums. Multivariate analysis was done based on principle component and cluster analyses in which grain and forage sorghum genotypes were combined. Results: Analysis of variance revealed significant differences (P < 0.001) among the genotypes for biomass, grain yield, plant height and days to flowering indicating the possibilities of improving

NARROW SENSE HERITABILITY AND GENE EFFECTS FOR LATE LEAF SPOT RESISTANCE IN VALENCIA GROUNDNUTS

Late leaf spot (LLS), Phaeoisariopsis personata (Berk. and Curtis) Deighton, is one of the most important foliar diseases of groundnut (Arachis hypogaea L.) worldwide. Effective chemical control is heavily reliant upon multiple fungicide applications which are costly for resource poor farmers in Sub-Saharan Africa. The deployment of resistant cultivars is a better option to control this disease in groundnut. A study was conducted to determine narrow sense heritability and gene action controlling LLS resistance in Valencia groundnut materials. The materials used included six generations; F 1 , F 2 , F 1 backcrosses to the susceptible BC 1 P 1 and resistant BC 1 P 2 parents, and their respective parental lines of crosses between NuMex-M 3 × ICGV -SM 02501, Valencia C × ICGV-SM 02501and Redbeauty × ICGV -SM 03590. All the test materials were evaluated at the National Semi-Arid Resources Research Institute (NaSARRI) at Serere in Uganda. Narrow-sense heritability estimates were 12, 27 and 36%, for Redbeauty × ICGV-SM 03590, Valencia C × ICGV-SM 02501 and NuMex-M 3 × ICGV-SM 02501 crosses, respectively. Both additive and dominance gene effects contributed significantly to the inheritance of LLS resistance in all the crosses, except in Redbeauty × ICGV-SM 02501 where the effects of dominance were not significant.

Efficacy of albendazole, levamisole and ivermectin against gastro-intestinal nematodes in naturally infected goats at the National Semi-arid Resources Research Institute, Serere, Uganda

A study was conducted between April and July, 2011 to determine and compare the efficacy of albendazole (ABZ), levamisole (LVM) and ivermectin (IVM) against gastrointestinal nematodes in naturally infected Mubende and Boer crossbred goats at the National Semi-arid Resources Research Institute in Serere, Uganda. Forty Mubende goats and 31 Boer crosses were each blocked by age and sex and randomly assigned to four groups. The first group of each breed served as the untreated control, the second was treated with albendazole (5mg/kg BW), the third with levamisole hydrochloride and oxyclozanide (7.5 and 15mg/kg BW) and the fourth with ivermectin (0.2mg/kg BW). Each group included 7–11 animals. Treatments were administered with doses of goats in albendazole and ivermectin, and doses of sheep in levamisole, as recommended by the manufacturers. In the treated groups, goats received anthelmintics basing on individual weights. Fecal egg counts, expressed as eggs per gram and larval cultures were done on day zero before treatment and on day 13 after anthelmintic treatment. Efficacy for each anthelmintic was determined by the Fecal Egg Count Reduction Test (FECRT). In Mubende goats, ABZ, LVM, and IVM reduced FEC by 28.5%, 91%, and 98%, respectively. In Boer crosses, ABZ, LVM, and IVM reduced FEC by 11%, 84.88% and 78.47%, respectively. At a 95% CI, only IVM was more effective in Mubende goats than Boer crosses (t=2.564, p<0.05). This may indicate occurrence of anthelmintic resistance in the goat farming sector in Uganda. Further studies need to be done to clarify the state of efficacy of the commonly used anthelmintics covering different agro ecological zones and species of animals in Uganda.