Evaluation of performance of introduced yam bean (Pachyrhizus spp.) in Rwanda.

Root and tubers crops are key staple crops for both rural and urban populations in Rwanda and supporting more than nine million people living in densely populated areas and sustained on agriculture with diverse range of cultivated species. Yam bean (Pachyrizhus spp) was introduced for both its immediate utilization as a high-yielding root crop with high sugar, considerable micronutrient concentrations and protein content for subtropical regions compared to common grown tropical root and tuber crops (cassava, potato, sweetpotato and yam).The yields of these species are up to 100 tons fresh weight per hectare, with dry matter contents of up to 25%. Recent introduction of different yam bean accessions in different agro-ecological zones of Rwanda produced high yield storage roots. Higher storage roots yield with strict pruning was produced by Erosus genotype 209018 (111.33 t/ha) and genotype 209019 (108.00 t/ha) followed by Ahipa genotype 209029 with 76.33 t/ha respectively. Dry matter was relatively low with a range of 20.84-19.14 % for all introduced genotypes. As a root crop with capacity of fixing atmospheric nitrogen and which does not require good-quality soil and resists pests and diseases which can fix yields abundantly and produces well even in area with scanty rain, it might be well indicated for Rwand

Effect of maize intercrop plant densities on yield and beta-carotene contents of orange-fleshed sweetpotatoes

Despite efforts to demonstrate the value of orange-fleshed sweetpotato (OFSP) (Ipomoea batatas L.) and quality protein maize (Zea mays L.) in combating vitamin A and protein malnutrition, small land holdings by rural poor farmers still limit the crops’ overall production in Africa. As such, intercropping and optimum plant density in cropping systems will help farmers to improve productivity of the crop, and hence, improve household food and nutrition security. This study determined the effect of maize plant population, in a sweetpotato-maize intercrop, on yields and β-carotene content of two popular OFSP cultivars, Ejumula and NASPOT 9 O (Kabode). Each variety was intercropped with maize variety Longe 5, at three plant densities (i.e. 41,666, 55,555 and 88,888 plants ha-1), at Ngetta Zonal Agricultural Research and Development Institute in Uganda. While 55,555 plants of each OFSP cultivar were used for both sole and intercrops, the sole maize plot was 44,444 plants ha-1. Maize and sweetpotato were harvested at 120 and 135 days after planting, respectively. β-carotene content and yield in sweetpotato roots were significantly (P<0.05) reduced by high maize density. Irrespective of maize density, NASPOT 9 O produced more root yields than Ejumula. Land Equivalent Ratios of >1.2 were obtained at maize intercrop densities of 41,666 and 55,555 plants ha-1.Keywords: Ipomoea batatas, land equivalent ratio, Zea may

Composition and functional properties of yam bean (Pachyrhizus spp.) seed flour

Open Access JournalYam bean (Pachyrhizus spp.) is legume crop that not only produces edible roots but also has a high yield of unutilized seeds. Although the yam bean seeds are rich in protein, they are not used due to a high content of toxic rotenone. In this study, yam bean seeds were detoxified and the nutritional and functional properties of their protein determined to assess the proteins’ potential for applications. Seeds of 10 accessions (2 accessions of P. erosus, 4 accessions of P. ahipa and 4 accessions of P. tuberosus) were analyzed for proximate composition, pasting and functional properties (bulk density, least gelation concentration, water absorption capacity, oil absorption capacity, emulsifying capacity, emulsion stability, foaming capacity, foam stability and protein solubility). The results showed that yam bean seeds contained: 29.2 - 32.1 g/100g proteins, 31.3 - 33.0 g/100 g carbohydrates, 24.1 - 25.6 g/100g total fat, 7.5 - 8.1 g/100g crude fiber and 3.4 - 4.1 g/100g ash. The defatted P. erosus seed flour contained 45.6 - 48.8 g/100g protein, 32.6 - 36.5 g/100g total carbohydrate, 6.7 - 7.1 g/100g crude fiber, 6.0 - 6.4 g/100g ash and 5.2/100 g crude fat. The defatted yam bean seed flour exhibited relatively high protein solubility (68.0% - 70.4%), least gelation concentration (14%), water absorption capacity (2.8% - 2.9%) and oil absorption capacity (1.5%). The defatted flour exhibited emulsifying capacity of 35.7% - 36.0%, emulsion stability of 33.2% - 33.5%, foaming capacities of 42% and foam stability of 25.1% - 25.8%. With respect to pasting properties, the defatted yam bean seed flours exhibited pasting temperature of 80.0˚C - 81.3˚C, peak viscosity of 145.5 - 146.7 RVU, trough viscosity of 95.1 - 102.0 RVU, break down of 43.5 - 51.6 RVU, set back of 252.9 - 258.1 RVU and final viscosity of 348 - 360 RVU. The results show that yam bean seed has potential for use in both food and nonfood applications

Dry and starchy orange-fleshed sweetpotato farmer varieties: Implications for fighting vitamin A defiency in East and Central Africa.

Sweetpotato is a major staple and co-staple root crop for millions of the rural people in Africa. Recently, it has been demonstrated to be of human health importance by combating vitamin A deficiency. This paper is a summary review of recent findings on the orange-fleshed sweetpotato (OFSP) farmer varieties (FV) from East Africa (EA) and their potential contribution to combat vitamin A deficiency (VAD) in Africa. Between 2000 and 2006, scientists from East and Central Africa collected several OFSP varieties from farmers' fields together with the white- and creamfleshed sweetpotato (WFSP) farmer varieties. Subsequent characterization studies using selected EA and exotic germplasm revealed critical findings for the future use of OFSP FV in Africa. Overall, molecular characterization showed that EA germplasm is distinct from non-African germplasm. It also showed that OFSP FV and WFSP FV from EA are very closely related. The two findings address suspicions that OFSP FV are of exotic origin. The OFSP FV differed from exotic OFSP on root dry matter (DM), starch and sucrose properties. Whereas the exotic OFSP are characteristically 'sweet and moist' (DM ≈ 25.0%, starch ≈50.0% and sucrose ≈ 10.3%), OFSP FV had characteristically high DM (≈33.0%), high starch (≈ 65.0%) and similar to the WFSP FV. It is these qualities that make sweetpotato a staple crop in Africa. However, root â-carotene content (BC) of some OFSP FV ['Ejumula', 240pmm; 'Carrot C', 259 ppm; 'Mayai', 264 ppm; and 'Zambezi', 233 ppm] nearly equaled that of 'Resisto' (271ppm), one of the popular OFSP cultivars in USA. These were shown to meet ≥400% of recommended daily allowance (RDA) with 250 g serving to a 5-8 year old child Other light orange-fleshed FV like 'ARA244 Shinyanga', 'K-118', 'K-134', 'K-46', 'PAL161', 'Sowola6', 'SRT52', and 'Sudan' had lower root BC than 'Resisto' and were shown to meet between 50-90% RDA of the child. In conclusion, OFSP FV from EA might show similar adaptation to sub- Sahara African environments as their sister WFSP and have a big potential to alleviate VAD. Also, breeding for acceptable high DM and high starch OFSP varieties for African consumers seems possibl

Analysis of and recommendations for scaling cassava agribusiness seed systems models in Rwanda

The objective of this study was to analyze the scalability of the cassava seed agribusiness models that have been supported under the CASS project in Rwanda. Phone interviews with key-informants formed the basis for analyzing the agribusiness cases. The study presents general conclusions, bottlenecks and recommendations for further development and scaling of cassava agribusiness seed models in Rwanda. General conclusions The key-informant interviews allowed us to draw the following conclusions: 1. None of the seed agribusiness models are currently ready for scaling 2. Agribusiness models are not yet being used beyond the CASS project 3. Likelihood of continued agribusiness model development varies across models 4. There is a lack of strategies or plans that go beyond the CASS project 5. No major concerns regarding the responsible scaling of the agribusiness models are reported, but unclear how the models target different groups of cassava farmers 6. Public-private partnerships seem to be preferred modality for scaling cassava seed agribusiness models 7. The “what’s in it for me” needs to be clarified for key stakeholders Cross-cutting bottlenecks There are a number of sector-wide bottlenecks that could negatively affect the scaling of clean cassava seed agribusiness models in Rwanda: 1. Limited investment in developing the cassava sector 2. Incentives for investing in clean cassava seed are currently not strong enough 3. There exist key capacity gaps among cassava farmers, seed multipliers and cooperatives 4. There is a lack of clear stakeholder scaling role division and coordination 5. Limited understanding of the market for seed and roots 6. Limited information flow and demand creation amongst farmers for new varieties and clean seed Recommendations and next steps The following recommendations and next steps could be considered by the CASS project team: 1. Distinguish between scaling within the agribusiness cases, and scaling the agribusiness models 2. Develop long-term and/or exit strategies with the agribusiness case stakeholders 3. Continued investment in fine-tuning those models that seem promising 4. Deepen understanding of stakeholder willingness to pay/invest 5. Co-investment models with scaling partners to ensure ownership and sustainability The above conclusions, bottlenecks and recommendations are in line with the main objective of the CASS project which was to “develop, test and tailor different types of cassava agribusiness seed system models with and for different groups of farmers”. The nature of development, testing and tailoring implies by default that some models will show more 2 potential for sustainability and scaling than others. We would like to emphasize that this is normal and what should be expected when designing and piloting new seed system models. The scaling recommendations and bottlenecks identified in this report should therefore be interpreted as giving an early indication of how key-informants perceive the scalability potential of the various cases and models. Bottlenecks or risks should not necessarily stop agribusiness case or model development, but taken into account when making decisions on which case and model development to continue and how. What is very important is to see projects such as CASS as temporary interventions that can support capacity sharing, stakeholder collaboration or independent agribusiness seed model testing. Project teams and broader stakeholders should always think beyond the project to ensure that there is ownership, sustainability and continuity to ensure diverse groups of farmers have access to clean and affordable cassava seed. More detailed information on the conclusions, bottlenecks and recommendations can be found in Section 4

Sweetpotato selection releases: Lessons learnt from Uganda

The National Sweetpotato Programme of the National Agricultural Research Organisation (NARO) in Uganda released 14 sweetpotato cultivars between 1994 and 2005. Of the released cultivars, six have gained importance in local Ugandan markets and in export trade to Europe and two are being used as parental sources for high drymatter (>30%), sweetpotato virus disease (SPVD) and nematode resistance in hybridization schemes, and in the genetic mapping work in joint international collaborative research. Two orange-fleshed sweetpotato (OFSP) cultivars, namely, Ejumula, and SPK004 (Kakamega), high in beta-carotene (the precursor for vitamin A) arespreading rapidly for combating widespread vitamin A deficiency in Uganda. The major steps leading to the release of Kakemega and Ejumula are used to illustrate the experience of the Ugandan sweetpotato breeding programme sustained activities for a decade, and lessons learnt are highlighted. The sustained breeding activitieshave led to a vibrant and robust program, increased international and south to south collaboration, increased partnership and alliances; shifted research focus from production to production per se and quality (nutrition), resulting into significant and relevant agricultural research. The lesson here is that it takes a long time to develop technologies, disseminate and commercialize them. It also requires commitment by the donor, government, scientists, farmers and other stakeholders for effective commercialization of the developed technologies

EFFECT OF MAIZE INTERCROP PLANT DENSITIES ON YIELD AND \u3b2-CAROTENE CONTENTS OF ORANGE-FLESHED SWEETPOTATOES

Despite efforts to demonstrate the value of orange-fleshed sweetpotato (OFSP) ( Ipomoea batatas L.) and quality protein maize ( Zea mays L.) in combating vitamin A and protein malnutrition, small land holdings by rural poor farmers still limit the crops\u2019 overall production in Africa. As such, intercropping and optimum plant density in cropping systems will help farmers to improve productivity of the crop, and hence, improve household food and nutrition security. This study determined the effect of maize plant population, in a sweetpotato-maize intercrop, on yields and \u3b2-carotene content of two popular OFSP cultivars, Ejumula and NASPOT 9 O (Kabode). Each variety was intercropped with maize variety Longe 5, at three plant densities (i.e. 41,666, 55,555 and 88,888 plants ha-1), at Ngetta Zonal Agricultural Research and Development Institute in Uganda. While 55,555 plants of each OFSP cultivar were used for both sole and intercrops, the sole maize plot was 44,444 plants ha-1. Maize and sweetpotato were harvested at 120 and 135 days after planting, respectively. \u3b2-carotene content and yield in sweetpotato roots were significantly (P<0.05) reduced by high maize density. Irrespective of maize density, NASPOT 9 O produced more root yields than Ejumula. Land Equivalent Ratios of >1.2 were obtained at maize intercrop densities of 41,666 and 55,555 plants ha-1.Malgr\ue9 les efforts visant \ue0 d\ue9montrer la valeur nutritionnelle en combinaison de la patate douce \ue0 chaire orange (OFSP) ( Ipomoea batatas L.) et du ma\uefs \ue0 grande valeur proteique ( Zea mays L.) dans la lutte contre la malnutrition li\ue9e au manque de la vitamine A et de proteine, les petits producteurs Africains continuent de limiter les rendements de leur cultures. A cet effet, l\u2019association des cultures doubl\ue9e d\u2019une densit\ue9 optimale des plants dans les systems de cultures, aiderait les producteurs \ue0 am\ue9liorer les rendements de leurs cultures et par consequent am\ue9liorer la qualit\ue9 de vie dans les m\ue9nages et assurer la s\ue9curit\ue9 alimentaire. La pr\ue9sente \ue9tude a d\ue9t\ue9rmin\ue9 l\u2019effet de la densit\ue9 des plants de ma\uefs, dans une culture associ\ue9e avec la patate douce sur le rendements et la teneur en \u3b2-carotene de deux vari\ue9t\ue9s populaires de patate douce OFSP, Ejumula et NASPOT 9 O (Kabode). Chaque vari\ue9t\ue9 a \ue9t\ue9 plant\ue9e en association avec la vari\ue9t\ue9 de ma\uefs Longe 5, \ue0 trois diff\ue9rentes densit\ue9s (i.e. 41,666, 55,555 et 88,888 plants ha-1), et ceci \ue0 l\u2019Institut Zonale de Developpement et de Recherche en Agriculture de Ngetta en Ouganda. Pendant que la densit\ue9 55,555 plants de chaque vari\ue9t\ue9 de OFSP a \ue9t\ue9 utilis\ue9 dans la culture solitaire et en association, la culture solitaire de ma\uefs \ue9tait \ue0 44,444 plants ha-1. Ma\uefs et patate douce ont \ue9t\ue9 r\ue9colt\ue9s respectivement \ue0 120 et 135 jours apr\ue8s. La teneur en \u3b2-carotene et le rendement en tubercules de patate douce ont \ue9t\ue9 r\ue9duits de fa\ue7on significative (P<0.05) par une densit\ue9 forte de ma\uefs. Quelle que soit la densit\ue9 de ma\uefs, NASPOT 9 O a produit plus de tubercules qu\u2019Ejumula. Le ratio \ue9quivalent \ue9tait >1.2 pour une densit\ue9 de ma\uefs de 41,666 et 55,555 plants ha-1, en culture d\u2019association

Evaluation of the American yam bean (Pachyrhizus spp.) for storage root yield across varying eco-geographic conditions in Uganda

Open Access Article; Published online: 15 June 2019The American yam bean (Pachyrhizus spp.) is a legume crop that is exclusively used for its storage roots. The seeds are inedible due to presence of toxic rotenone. It produces high storage root yields comparable of major root crops like cassava or sweetpotato. And flower pruning more than doubles its root yield performance. Using twenty five yam bean accessions, the current study aimed to determine root yield stability and adaptability, and presence of yam bean production mega environments in Uganda. Trials were planted at three stations, Namulonge, Serere, and Kachwekano during two consecutive seasons of 2011. Fresh storage root yields were significantly different (p < 0.05) across locations with the ideal location being Namulonge (fresh storage root yield of 10.1 t ha-1), followed by Serere (8.0 t ha-1), and Kachwekano (3.1 t ha-1). Results of AMMI analysis indicated the presence of genotype-by-environment interaction for fresh storage root yield. Through AMMI estimates and GGE visual assessment, genotype 209017 was the highest yielding with mean yield of 20.7 t ha-1. Genotype 209018 with mean yield of 15.5 t ha-1 was the most stable and adapted accession in the entire discriminating environment in Uganda. From the environmental focusing plot, the six environments were grouped into two putative mega environments for yam bean production