How sweet potato varieties are distributed in Uganda: actors, constraints and opportunities

Sweet potato varieties are distributed in Uganda by three systems: formal, project-based and informal. In a partial formal system, the National Sweetpotato Program (NSP) breeds and tests both orange (O)- and white (W)-fleshed sweet potato (FSP) varieties. The NSP and other national institutions provide vine stocks of mostly OFSP varieties to project-based seed systems involving large private sector multipliers, which are found predominantly in east and central Uganda. These are mainly either cooperatives derived from smallholder groups organized by projects or are individual farmers with large holdings who had hosted NSP variety trials. The private sector multipliers sell planting materials of released varieties to projects, which distribute them free to selected households. Projects buy hundreds and occasionally thousands of sacks of vines but they distribute them to only a limited number of needy households and for only one or a few seasons. The informal system functions predominantly in areas with a long dry season, in which vines cannot survive. Its vine multipliers use the wetter lowlands to maintain mostly landraces, which they sell as small bundles of vines to many smallholders at the onset of the rains. Very few multiply released varieties. Thus, with a ready market, the system is sustainable but quantities sold are price limited. All vine multipliers supplied healthy planting material. It is proposed that the NSP should aim their trials of new varieties at informal vine multipliers and projects should supply vines to these multipliers in order to improve their access to them. This would promote the sustainable distribution of vines, including new varieties, over a greater area and to a larger number of farmers.     

不同海拔生产的烟草种子其品种经济性状效应分析

通过对不同海拔产地生产的烟草种子进行品种多年多点区域试验,发现同一品种在不同海拔产地生产的烟草种子其品种经济性状表现、适应性与稳定性均无显著差异;但不同品种在不同地点生产的烟草种子其品种经济性状表现差异显著,品种经济性状的适应性和稳定性也存在显著差异。     

Prioritising quality traits for gender-responsive breeding for boiled potato in Uganda

Using quantitative, qualitative and sensorial data collected from western (Kabale) and central (Rakai) Uganda, this paper identifies and describes gender-responsive traits preferred in varieties for the boiled potato market. These traits are aggregated into a product profile to support breeding programme design and decision-making that will increase probability of variety acceptance. An interdisciplinary and participatory methodology was used to collect data on socio-economic on trait preferences, processing and organoleptics and finally, to develop a lexicon through a sensorial panel. Characteristics that were important to both men and women, such as red skin and yellow flesh, are linked to market preferences. Women-only preferred characteristics such as big size and mealiness are linked to processing efficiency and eating quality. Besides agronomic traits, breeders must consider factors such as gender roles, social norms, and market preferences traits that guide farmers and other food chain actors in their selection of new varieties.     

Innovative and beneficial informal sweetpotato seed private enterprise in northern Uganda

Research conducted in the informal sweetpotato seed (vines) supply system in the Gulu region, northern Uganda (2013–2015) revealed a diverse set of actors using private enterprise in a range of selling and marketing channels. The different channels offer an efficient and effective marketing system, providing different services and conveniences for farmers at different prices. The actors include local vine multipliers, traders, dry season root farmers, transporters and town sellers. The local multipliers and dry season root farmers grow crops during the dry season in swampy areas and sell the vines in the following rainy season to the many farmers who lack access to such areas and therefore lack vines to plant. The presentation and discussion of this case study adds to an expanding argument in the literature for increased attention to support actors in informal food crop sectors who are providing sustainable production and marketing systems on a platform of beneficial and innovative private enterprise. Through their commercial operations, vine multipliers and other actors can effectively meet the demand of customers and at the right time and place. With suitable dissemination programmes installed, these actors could also offer access to new varieties otherwise unavailable to the majority of farmers.     

Yield effects of rust-resistant wheat varieties in Ethiopia

Breeding crops for disease resistance is a sustainable approach to reduce yield losses. While significant research on the adoption and impacts of improved crop varieties exists, most studies have analyzed yield effects in general without distinguishing between different varietal traits and characteristics. Here, panel data from wheat farmers in Ethiopia were used to compare improved varieties that are resistant to stripe rust (caused by Puccinia striiformis f. sp. tritici) with improved susceptible and traditional susceptible varieties. Production function estimates suggest that improved resistant varieties raise effective yields by 8% in comparison to local susceptible varieties. The yield difference between improved resistant and improved susceptible varieties is positive but small because rust levels were not very high in the years under study. However, under drought and other abiotic stresses, improved varieties – with and without resistance to stripe rust – performed notably worse than local varieties. The worse performance under abiotic stress may explain why many farmers have recently switched back to growing traditional varieties. Sustainable adoption needs a combination of various traits in the same varieties, including high yield potential, grain quality, disease resistance and tolerance to drought and other production stresses.     

The influence of starch pasting properties and grain protein content on water uptake in barley

Steeping is the first operation of malting and its purpose is to increase the water content of the grain up to 43–46%; however, such a simple step encompasses several metabolic processes that affect germination and the final malt quality. The aim of this study was to evaluate the effect of initial grain protein (GP) content and starch pasting properties, measured using the Rapid Visco Analyser (RVA) on water uptake in different barley varieties. The partial least squares (PLS2) regression algorithm was used to compare the two data matrices, the independent block of variables X (RVA data and GP) and the dependent block Y (water uptake at different steeping times). The first two PLS2 loadings explained 65 and 23% of the total variation in water uptake in the barley samples. Water uptake at 1 and 2 h was poorly explained by the PLS2 models, while after 5 h the models explained more than 40% of the variability. The results from this study showed that, although a relationship between GP and water uptake exists, it is not universal for all the varieties, indicating that the relationship between GP and water uptake is varietal dependent. Copyright © 2014 The Institute of Brewing & Distilling     

Relevance of informal institutions for achieving sustainable crop intensification in Uganda

Informal institutions play an important role in the socio-cultural lives of rural communities in Uganda. However, little attention is given in research and development to understanding the influence of informal institutions in efforts to achieve Sustainable Crop Intensification (SCI). Such evidence is, however, pertinent to addressing low crop productivity by designing and implementing interventions that take into account the socio-cultural and institutional barriers and opportunities for SCI. This paper analyzes the influence of informal institutions on farmers’ access to land resources, financial resources, and farm inputs. The analysis is based on qualitative and quantitative data collected between January and May 2015 using 61 in-depth interviews, field surveys with 120 farmers and 18 gender-segregated focus group discussions in Eastern and Southwestern Uganda. Results indicate that informal institutions play a central role in enhancing farmers’ investment in SCI interventions by facilitating access to land through inheritance, land rentals, and labor sharing arrangements, although they are biased against non-clan members and female members of the communities. Informal institutions also enable access to financial resources by farmers at lower transaction cost compared to formal financial institutions. Yet, the informal institutions face challenges related to poor rule enforcement and limited financial reserves. The contribution of informal institutions in improving farmers’ access to (i) external farm inputs, (ii) serving as forums for knowledge sharing and (iii) regulating quality of farm inputs is minimal. Findings imply that development interventions could benefit from using informal institutions as entry points for investment in SCI and building on institutions’ strengths in influencing access to land and financial resources. Policies and programs that promote the SCI approach need to recognize the role of informal institutions for increased implementation and impact.     

Optimizing agbelima production: varietal and fermentation effect on product quality

The variety of cassava used for processing has been shown to influence the physico-chemical, functional and other quality characteristics of some cassava products. Thus, the effects of varietal differences and fermentation time on some quality indices of agbelima, a fermented cassava product, was investigated with the objective of optimizing production. Three improved cassava varieties, TMS 4(2)1425, TMS 50395, TMS 30572 and two local varieties, Bosomensia and Biafra were investigated at fermentation times of 0, 24, 48 and 72 h. Quality parameters assessed included total titratable acidity, pH, textural properties and colour characteristics. All the parameters were significantly (P 0.01) affected by both varietal differences and fermentation time. The interaction between varietal difference and fermentation time were also highly significant (P 0.01) for all the parameters assessed. The results of this study show that the selection of cassava varieties for processing and the duration for fermentation are critical to the quality of the final agbelima product.     

Resurgence of minority and autochthonous grapevine varieties in South America: a review of their oenological potential

In contrast with the general trend of producing wine from the most famous grapevine varieties, associated with the French paradigm, such as Cabernet-Sauvignon, Merlot, Pinot Noir, Syrah, Sauvignon Blanc, and Chardonnay, there is a tendency to revalorize and preserve minority or autochthonous grapevine varieties worldwide. The South American wine region, where most of the varieties derived from varieties brought after European colonization, is not exempt from this. This has allowed new wines to be provided with distinctive identities that are markedly different from the current homogeneous wine production. Moreover, varietal homogenization increases vineyard genetic vulnerability in relation to the emergence of grapevine diseases, to which the commonly cultivated varieties are not resistant. This review summarizes the oenological potential of minority or autochthonous grapevine varieties cultivated within the South American wine region, focusing on Argentina, Chile, and Bolivia. © 2019 Society of Chemical Industry     

Development of a food product profile for boiled and steamed sweetpotato in Uganda for effective breeding

This study sought to understand user preferences of raw, boiled and steamed sweetpotato, a staple food in Uganda. A sequential methodology involving state of knowledge review, gendered food mapping, processing diagnosis and consumer testing was used in Lira and Kamwenge districts. Preferred raw sweetpotato characteristics were large roots (≥ 3 cm diameter) with a sweet taste, smooth skin and hard texture, while mealiness, sweet taste and good sweetpotato smell were important attributes for boiled sweetpotato. Processors, mostly women, highlighted ease of peeling and sappiness of raw roots. There were gender differences in quality characteristic preferences and perceived importance. The released variety, NASPOT 8, had the highest overall liking in Kamwenge and was well liked in Lira. Penalty analysis of consumer data showed that sweetness and firmness were key drivers of overall liking. The results will support breeding programmes in meeting specific end-user product profiles, selection criteria and uptake of new varieties.     

SOME BARLEY GRAIN AND GREEN MALT PROPERTIES AND THEIR INFLUENCE ON MALT HOT-WATER EXTRACT: II. PROTEIN,PROTEINASE AND MOISTURE

This paper continues the study of variation between varieties in some properties of barley and malt and examines protein-related characters and moisture uptake. Initial rate of moisture uptake was more closely related to enzyme activities than maximum moisture content. Significant varietal variation was found in all characters and this variation was greater than environmental variation with the exception of grain nitrogen concentration. In the endosperm endopeptidase activity was the character most highly correlated with malt hot water extract (HWE). The combined influence of protein- and β-glucan-related characters was investigated and the relative influence of each group of characters on HWE varied in different sections of the grain. In the endosperm the protein- and β-glucan-related characters accounted for 30% and 60% of the variation in HWE respectively.     

The implication of kernel phenology in convening resistance to storage weevil and varietal development in sorghum

Storage weevil is a major biotic insect pest attacking sorghum during late harvest or in storage condition. In developing countries, the infestation can be up to 83% within first six months, and may cause grain loss of 15–77% within the period. Kernel phenotypic characteristics such as pericarp thickness, testa, hardness and kernel size contributes to host plant resistance; through provision of physical barrier for insect penetration and space for oviposition. These traits have connections with several biochemicals associated with antibiosis and antixenosis effects to storage weevils including phenolic compounds. On contrary, little has been reviewed regarding the potential of these traits in varietal development. The insufficient collated information makes weevil management difficult. Both conventional and genomics approaches could be useful in transferring source of resistance to preferred sorghum cultivars for better management of weevils.     

The effectiveness of extension strategies for increasing the adoption of biofortified crops: the case of quality protein maize in East Africa

Biofortified crops can be promoted with extension strategies based on their agronomic qualities, nutritional qualities, or both, but the effectiveness of these different strategies has so far not been studied. Since 2003, quality protein maize (QPM) has been disseminated using both approaches in East Africa. This study therefore analyzes the effectiveness of promoting biofortified crops based on their agronomic and their nutritional qualities, using the adoption of QPM cultivars in East Africa as an example. A random sample survey was conducted in Ethiopia, Kenya, Tanzania, and Uganda, with 423 households from QPM extension areas and 539 households from similar areas outside the extension zone. Propensity score matching and regression analysis were used to assess determinants of QPM adoption, including farmers’ awareness of QPM, understanding of its nutritional benefits, and evaluation of agronomic performance to evaluate the agronomic and nutritional extension strategies. Results showed high familiarity with QPM, but low understanding of nutritional benefits. Farmers evaluated QPM varieties as equal or superior to conventional maize for post-harvest traits, but not always for agronomic traits (in particular yield in Ethiopia and Tanzania). Adoption in extension areas varied from 73 % in Uganda and 25 % in Tanzania to none in Kenya. Key factors that increased adoption were farmers’ participation in extension, having heard of QPM, higher overall evaluation ratings of QPM vs. conventional maize varieties, and understanding of QPM’s nutritional benefits. Agronomic performance was found to be more important than an understanding of nutritional benefits. For biofortified crops to be adopted and have a nutritional impact on target populations, they should, first and foremost, be agronomically equal or superior to conventional varieties. If farmers are convinced of the agronomic performance of biofortified crops, additional gains in adoption can be achieved by focusing extension efforts on imparting to farmers knowledge of the benefits of biofortified crops for human nutrition.     

我国食用植物油市场的挑战及机遇

我国食用油产业发展迅速,但仍然面临各种挑战。通过对我国食用油市场的发展现状、加工过程中危害物质深度分析欠缺、小品种油料资源的全面化市场调研欠深入、植物油营养评价和特殊人群的专用食用调和油研究开发不足等方面进行分析,提出我国食用植物油市场面临机遇与前景展望,推广油脂精准适度加工新模式,系统开发我国油料资源,研究食用油营养学价值,开发特殊人群的专用食用调和油,为推动油脂加工业的高质量发展提供参考建议。     

Tannin content of pulses: Varietal differences and effects of germination and cooking

The tannin content of different varieties of pigeonpea, chickpea, blackgram and greengram were estimated. Significant varietal differences were observed in the tannin content of the four pulses. Decortication of the pulse resulted in 83–97% loss of tannin. As a result of overnight soaking in water, 50% of tannin was lost in pigeonpea and chickpea while in blackgram and greengram the loss was 25%. When germination was continued for 48 h, a further 10% loss of tannin was observed in pigeonpea and chickpea varieties and 25% loss in blackgram and greengram varieties. Cooking of raw pulse brought about a 70% decrease in their tannin content. Loss of tannin during germination may be due to enzymatic degradation. Thus traditional methods employed for pulse processing are able to remove a major part of the tannin present in the pulse.     

Application of the TOA-MD model to assess adoption potential of improved sweet potato technologies by rural poor farm households under climate change: the case of Kabale district in Uganda

Sweet potato technologies that increase productivity, such as drought resistant varieties and virus free planting material are being promoted in order to reduce the vulnerability of poor farm households to climate change. In this paper, the Trade-off Analysis, Minimum Data Model Approach (TOA-MD) was used to assess the adoption potential of these technologies by resource poor farmers under climate change in Uganda. The model was calibrated and validated using household survey data collected in 2009 from Kabale district. To simulate adoption potential, the base system data was generated from household data and adjusted to reflect impact of climate change on crop yields and prices by 2050. The percentage increase in yields resulting from the use of climate resilient sweet potato technologies were used to estimate yields for alternative systems based on the results from sweet potato trials by the National Agricultural Research Organization (NARO), Uganda. Adoption potential of sweet potato technologies varied across altitudes. Compared with the high and lower altitudes, adoption potential is lowest at moderate altitude despite higher yields and lower costs of production. Paying farmers to adopt new sweet potato technologies is economically rational at the higher and moderate altitudes but not at the lower altitudes. The provision of free planting material (subsidy) for the evaluated technologies resulted in a modest increase of 2 % in adoption potential. Therefore, providing this as a way of increasing adoption of sweet potato technologies to reduce vulnerability of poor farm households to climate change will have a very small impact. Instead, climate change adaptation policy should focus on creating enabling environments for farmers to market their produce so as to raise returns and reduce the opportunity costs of climate change adaptation strategies.     

Relative quantification of <Emphasis Type="Italic">Vitis vinifera</Emphasis> L. varieties in musts by microsatellite DNA analysis

Varietal wines are defined as made primarily from a single variety of grape, which is identified on the label. However the inclusion of other varieties in their production is permitted under defined percentages. The fact that different grape varieties/varietal wines present far different economical values can attract fraudulent practices. Thus the development of methods, which allow the quantification of those varieties, is of crucial importance. The first approach to the method for the relative quantification of must containing two varieties based on microsatellite DNA analysis is presented. Quantification was achieved by densitometry measurements of the amplification products of the pooled varieties, obtained with loci VVMD6 and VVMD7, after their separation and staining on polyacrilamide gels. We have found that a good correlation between the proportion of each variety in must and the signal intensity of the alleles are dependent on the variety (varietal effect) and the microsatellite locus used. The relative quantification of musts can be accomplished by the presented method depending on the presence of overlapping alleles, and the composition of the varieties and their relative amounts.     

Amino acid composition of two Italian durum wheat varieties and their semolina

Two Italian durum wheat varieties and their semolina were analysed for protein content and amino acid composition. There was a difference in protein content between the two varieties. The concentration (in protein) of lysine, methionine and phenyl alanine was equal in both varieties. A large difference was found in glutamic acid and valine. A slight difference was found in other amino acids. There was a difference in the concentration of amino acids between wheat and its semolina. The biological value was equal in both varieties. The difference in results is attributed to the varietal difference.     

Varietal identification of single seeds of barley by analysis of hordein polypeptides

Methods for the extraction and separation of hordein fractions from single or half-seeds of barley have been evaluated. Sodium dodecylsulphate-polyacrylamide gel electrophoresis at pH 8.9 gave rapid and reproducible separations of reduced and alkylated hordein, and this system was used to analyse hordein fractions from 88 barley varieties. On the basis of this character the varieties can be divided into 29 groups, each containing between one and 25 varieties. The largest group can be further divided into four subgroups on the basis of minor hordein polypeptide differences revealed by a second electrophoretic system, urea polyacrylamide gel electrophoresis at pH 4.6. Of the samples of the varieties studied, all except five contained seed homogeneous with respect to hordein polypeptide pattern. It is concluded that analysis of hordein polypeptide patterns from single seeds is of great potential value, both for the commercial identification of grain samples and as an aid to existing techniques for the establishment of varietal distinctness.