Cassava whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), in sub-Saharan African farming landscapes: a review of the factors determining abundance

Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) is a pest species complex that causes widespread damage to cassava, a staple food crop for millions of smallholder households in Sub-Saharan Africa. Species in the complex cause direct feeding damage to cassava and are the vectors of multiple plant viruses. Whilst significant work has gone into developing virus-resistant cassava cultivars, there has been little research effort aimed at understanding the ecology of these insect vectors. In this review we critically assess the knowledge base relating to factors that may lead to high population densities of Sub-Saharan African (SSA) Bemisia tabaci species in cassava production landscapes of East Africa. We focus first on empirical studies that have examined biotic or abiotic factors that may lead to high populations. We then identify knowledge gaps that need to be filled to deliver long-term sustainable solutions to manage both the vectors and the viruses that they transmit. We found that whilst many hypotheses have been put forward to explain the increases in abundance witnessed since the early 1990s, there are little available published data and these tend to have been collected in a piecemeal manner. The most critical knowledge gaps identified were: (i) understanding how cassava cultivars and alternative host plants impact B. tabaci population dynamics and its natural enemies; (ii) the impact of natural enemies in terms of reducing the frequency of outbreaks and (iii) the use and management of insecticides to delay or avoid the development of resistance. In addition, there are several fundamental methodologies that need to be developed and deployed in East Africa to address some of the more challenging knowledge gaps

Situation of ticks and seroprevalence of Theileria parva in two farming systems in Nakaseke and Nakasongola districts of Uganda

This study delved into the composition of ticks, prevalence of Theileria parva and management of East Coast Fever in Nakaseke and Nakasongola districts of Uganda. The tick challenge on animals was assessed and whole blood was collected for determination of seroprevalence of Theileria parva using Enzyme-Linked Immunosorbent Assay. Majority (82.3 percent) of the cattle were found to be infested with Rhipicephalus appendiculatus (88.2 percent), Ambryomma variegatum (7.5 percent) and Rhipicephalus evertsi (4.3 percent). Majority (80.7 percent) of the respondents believed that tick infestation was severe and regularly managed using acaricides (65.3 percent). In the pastoral farming system, no ticks were found on calves below 6 months of age. In the mixed crop-livestock farming system, all cattle age groups were exposed to the ticks. The seroprevalence of T. parva varied among age groups of cattle in both farming systems. There was moderate correlation between the mean number of R. appendiculatus ticks and seroprevalence of T. parva (r = 0.47). Association was established between mean number of ticks and farming system (p = 0.019) and percentage positivity of T. parva and farming system (p = 0.007). Theileria parva was prevalent in the two farming systems despite frequent application of acaricides. Thus, the study provides evidence of the tick-borne disease pathogens and vectors responsible for ECF, R. appendiculatus being the principal tick species infesting cattle in the area. Creation of community-based technical and advisory services for livestock health management is recommended

Immunization against east coast fever by infection and treatment method in Uganda

East Coast Fever (ECF) caused by Theileria parva is known in Uganda as the must important tick-horne disease of cattle fora long time. The 1}apcr describes research efforts conducted mainly in Kenya and Uganda towards the development andtesting of the infection and tre:ltment method of immunization against ECF. This method has now been introduced onprivate farms and it is accepted in Uganda

Quantitative Trait Loci Mapping in Maize for Resistance to Larger Grain Borer

Storability of maize grain is constrained by the larger grain borer (LGB) (Prostephanus truncatus). Host plant resistance is the most feasible way to manage LGB among smallholder farmers. Breeding for resistance to this pest inmaize is dependent on understanding genetic mechanisms underlying the resistance. The objective of this study was to map quantitative trait loci (QTL) associated with LGB resistance in tropical maize. A mapping populationof 203 F2:3 derived progenies was developed from a cross between susceptible and resistant inbred lines.The F2:3 progenies were crossed to a tester and testcrosses evaluated across six environments, followed by screening for resistance to LGB. Data was collected on husk cover tip length, and grain texture in the field. Biochemical traits were analyzed on the maize grain. Harvested grain was evaluated for resistance and data recorded on grain damage, weight loss, and several insects. Grain hardness was measured as a putative trait of resistance. Univariate analysis of variance for all the traits was done using the general linear model of the statistical analysis system.Genetic mapping was done using Joinmap 4, while QTL analysis was done using PLABQTL. The QTL for resistance were mapped to 6 out of the ten chromosomes. QTL for resistance traits were located in chromosomes 1, 5 and 9.Chromosome 1 had a common QTL linked to protein content, grain hardness, and husk cover tip length. Additive genetic effects were prevalent in all detected QTL. Overall, the studies show that breeding for resistance to LGB is possible

Breeding for bean anthracnose resistance: Matching breeding interventions with people’s livelihoods through participatory variety selection

The common dry bean is the main source of protein, food and income for the majority of rural smallholder farmers in Uganda especially the women and children, and any constraints hindering its production directly affects these vulnerable groups. Despite its importance, there has been an unmerited decline in bean production over the last few decades as a result of bean anthracnose disease. Breeding for genetic resistance to bean anthracnose and the use of participatory variety selection which aims primarily at accelerating the transfer of new lines to farmers’ fields, are the most practical and economical options for controlling anthracnose and popularising the new varieties to smallholders farmers.The objectives of this study were to introgress anthracnose resistance into existing susceptible market class varieties, generate segregating populations, make selections and conduct farmer participatory evaluation trials to identify new bean lines having characteristics that are preferred by both farmers and the market for release as new varieties.A total of 365 new bean lines were generated and 54 of these were introduced to 10 farming communities in four different ecological zones for evaluation using the participatory variety selection approach. Farmers were able to select eight promising lines, which were ear- marked for new variety release. Out of the eight lines, two have already been released.It can thus be concluded that the participatory variety selection acts as an entry point into the farming communities where new varieties are introduced to farmers. Furthermore, participatory variety selection is reliant on farmer preferences and rural livelihood dynamics

Protein and amino acid composition of different quinoa (Chenopodium quinoa willd) cultivars grown under field conditions in Ethiopia, Kenya, Uganda, and Zambia

Protein-energy malnutrition (PEM) remains a public health concern in most developing nations. In Africa, PEM can be attributed to monotonous diets based on cereals, roots, and tubers, with little or no protein of animal origin. Diversifying cropping systems to include protein dense pseudo-cereals such as Quinoa (Chenopodium quinoa Willd.) could help provide more protein in the diet of vulnerable populations. Quinoa is a crop with potential for biodiversification because it has a high nutritional value; however, it is underutilized in Africa, and information about the nutritional quality of the grain grown in contrasting environments is limited. Within the framework of FAO’s commemoration of 2013 as the ‘The International Year of the Quinoa’ (IYQ), a Technical Cooperation Programme (TCP) project was developed with some African countries to assess the capacity of quinoa to adapt to different agro-ecological regions and the nutritional quality of the resulting grain. For this study, we evaluated the protein content and amino acidprofile of three genotypes of quinoa that had been grown under diverse altitudes, soil, and climate conditions in Ethiopia, Kenya, Uganda, and Zambia. The mean protein content (g/100g) of Kancolla, Titicaca and BBR varieties grown in Africa ranged from 14.33 ±0.20 to 17.61 ±0.55, 14.23 ±0.25 to 16.65 ±0.55, and 13.13 ±0.2 to 16.23 ±0.49, respectively. On the other hand, the protein content (g/100g) of Kancolla, Titicaca, and BBR seeds grown in Peru was 13.80 ±0.10, 17.43 ±0.31, and 17.07 ±0.11, respectively. The Kancolla variety [grown in Ethiopia and Kenya] had a significantly higher protein content than that obtained from Peru [P < 0.001]. Regarding the profile of essential amino acids, Quinoa is essentially richer in methionine than most cereals. Levels of methionine were lower in the seeds grown in Africa compared to those from Peru [P < 0.001]. In terms of environmental influences, the protein content was relatively higher in quinoa seeds grown in high-altitude areas, where soils have a low pH and high nitrogen content. We conclude that Quinoa can be introduced to Africa, especially to high altitudes and warm regions where the soil has a low pH and high nitrogen content. Thecrop would be ideal for diversifying local diets. Key words: Africa, Agro-ecology, Chenopodium quinoa, protein, amino acid content, biodiversity, diet

Responses of tropical maize landraces to damage by Chilo partellus stem borer

The potential to manage insect pests using host-plant resistance exists, but has not been exploited adequately. The objective of this study was to determine the resistance of 75 tropical maize landraces through artificial infestation with Chilo partellus Swinhoe. The trial was laid in alpha-lattice design and each seedling was infested with five neonates three weeks after planting, over two seasons in 2009 and 2010. The number of exit holes, tunnel length, ear diameter, ear length, plant height, stem diameter, stem lodging and grain yield were measured and a selection index computed. GUAT 1050 was the most resistant with an index of 0.56, while BRAZ 2179 was the most susceptible with an index of 1.66. Ear characteristics were negatively correlated with damage parameters. The principal component biplot suggested that exit holes, cumulative tunnel length, leaf damage, cob diameter, stem lodging, selection index, ear and plant height contributed 71.2% of the variation in resistance. The mean number of exit holes and tunnel length for resistant landraces and resistant hybrid checks were similar; at 5.5 and 2.48 cm, respectively. The identified resistant landraces (GUAT 1050, GUAT 280, GUAT 1093, GUAT 1082, GUAT 1014, CHIS 114, and GUAN 34) could be used to develop C. partellus stem borer-resistant maize genotypes.Key words: Chilo partellus, ear length, exit holes, stem borer resistance, tunnel length

Protein and amino acid composition of different quinoa (chenopodium quinoa willd) cultivars grown under field conditions in Ethiopia, Kenya, Uganda, and Zambia

Protein-energy malnutrition (PEM) remains a public health concern in most developing nations. In Africa, PEM can be attributed to monotonous diets based on cereals, roots, and tubers, with little or no protein of animal origin. Diversifying cropping systems to include protein dense pseudo-cereals such as Quinoa (Chenopodium quinoa Willd.) could help provide more protein in the diet of vulnerable populations. Quinoa is a crop with potential for biodiversification because it has a high nutritional value; however, it is underutilized in Africa, and information about the nutritional quality of the grain grown in contrasting environments is limited. Within the framework of FAO’s commemoration of 2013 as the ‘The International Year of the Quinoa’ (IYQ), a Technical Cooperation Programme (TCP) project was developed with some African countries to assess the capacity of quinoa to adapt to different agro-ecological regions and the nutritional quality of the resulting grain. For this study, we evaluated the protein content and amino acid profile of three genotypes of quinoa that had been grown under diverse altitudes, soil, and climate conditions in Ethiopia, Kenya, Uganda, and Zambia. The mean protein content (g/100g) of Kancolla, Titicaca and BBR varieties grown in Africa ranged from 14.33 ±0.20 to 17.61 ±0.55, 14.23 ±0.25 to 16.65 ±0.55, and 13.13 ±0.2 to 16.23 ±0.49, respectively. On the other hand, the protein content (g/100g) of Kancolla, Titicaca, and BBR seeds grown in Peru was 13.80 ±0.10, 17.43 ±0.31, and 17.07 ±0.11, respectively. The Kancolla variety [grown in Ethiopia and Kenya] had a significantly higher protein content than that obtained from Peru [P < 0.001]. Regarding the profile of essential amino acids, Quinoa is essentially richer in methionine than most cereals. Levels of methionine were lower in the seeds grown in Africa compared to those from Peru [P < 0.001]. In terms of environmental influences, the protein content was relatively higher in quinoa seeds grown in high-altitude areas, where soils have a low pH and high nitrogen content. We conclude that Quinoa can be introduced to Africa, especially to high altitudes and warm regions where the soil has a low pH and high nitrogen content. The crop would be ideal for diversifying local diets

Conservation Farming and Changing Climate: More Beneficial Than Conventional Methods for Degraded Ugandan Soils

The extent of land affected by degradation in Uganda ranges from 20% in relatively flat and vegetation-covered areas to 90% in the eastern and southwestern highlands. Land degradation has adversely affected smallholder agro-ecosystems including direct damage and loss of critical ecosystem services such as agricultural land/soil and biodiversity. This study evaluated the extent of bare grounds in Nakasongola, one of the districts in the Cattle Corridor of Uganda and the yield responses of maize (Zea mays) and common bean (Phaseolus vulgaris L.) to different tillage methods in the district. Bare ground was determined by a supervised multi-band satellite image classification using the Maximum Likelihood Classifier (MLC). Field trials on maize and bean grain yield responses to tillage practices used a randomized complete block design with three replications, evaluating conventional farmer practice (CFP); permanent planting basins (PPB); and rip lines, with or without fertilizer in maize and bean rotations. Bare ground coverage in the Nakasongola District was 187 km2 (11%) of the 1741 km2 of arable land due to extreme cases of soil compaction. All practices, whether conventional or the newly introduced conservation farming practices in combination with fertilizer increased bean and maize grain yields, albeit with minimal statistical significance in some cases. The newly introduced conservation farming tillage practices increased the bean grain yield relative to conventional practices by 41% in PPBs and 43% in rip lines. In maize, the newly introduced conservation farming tillage practices increased the grain yield by 78% on average, relative to conventional practices. Apparently, conservation farming tillage methods proved beneficial relative to conventional methods on degraded soils, with the short-term benefit of increasing land productivity leading to better harvests and food security