Associating molecular markers with phenotypes in sweetpotatoes and liriopogons using multivariate statistical modeling

Two horticultural crops, the ornamental liriopogon and the sweetpotato [Ipomoea batatas (L.) Lam.], were analyzed for morphological, quantitative and molecular marker variation using Amplified Fragment Length Polymorphism (AFLP) and various multivariate statistical techniques. Ornamental cultivars in genera Liriope and Ophiopogon were analyzed for relatedness using AFLP marker data and statistical clustering methods. Marker data did not substantiate the separation of these two genera. Greater than 95 % of the total genetic variability present was attributed to within group variation (P \u3c 0.05). Trait-linked molecular markers were identified using Quantitative trait loci (QTL) analysis, logistic regression and discriminant analysis in the studies involving sweetpotato. The traits studied included dry matter content, virus disease resistance, root-knot nematode resistance, sugar content and -carotene content. Analysis of molecular variance found significant (P \u3c0.001) differences between two phenotypic groups from unrelated genotypes for dry matter data. Using 14 markers selected through discriminant analysis the phenotypic grouping was validated with a zero error rate. Eighty-seven F1 sweetpotato genotypes from a cross of ‘Tanzania’ and ‘Wagabolige’ landraces were used to generate AFLP and random amplified polymorphic DNA (RAPD) marker profiles for this study. One AFLP marker linked to sweetpotato chlorotic stunt closterovirus resistance and one RAPD marker linked to sweetpotato feathery mottle virus resistance previously identified by traditional mapping strategies were selected plus new markers. Two diverse F1 populations of sweetpotato were used to identify and select markers suitable for identification of plants possessing a resistant reaction to southern root-knot nematode race 3 [Meloidogyne incognita (Kofoid and White) Chitwood]. Results for plant nematode resistance indicated a binomial distribution among the genotypes for population 1 and a normal distribution for population 2. A comparison of the power of discriminant analysis models for southern root-knot nematode resistance class prediction achieved 88% classification efficiencies. An F1 population of 73 clones consisting of parents and half-sibs was grouped into 2 phenotypic classes based on their sugar and ß-carotene content. Logistic regression and discriminant analysis selected meaningful markers that had significant associations with each of the traits. These results validated discriminant analysis and logistic regression as meaningful trait-linked marker selection methods

Cost-benefit analysis of sustainable land and water management practices in selected highland water catchments of Kenya

Sustainable land management (SLM) strives to maintain and improve the agricultural production capacity of land. To achieve the goals of SLM, communities use various types of agronomic, vegetative, and structural practices. Despite the benefits of SLM practices, some farmers are reluctant to adopt them. An economic cost-benefit analysis of SLM practices is an important approach to demonstrate the benefits of appropriate SLM practices. This study was conducted to determine the effect of adopting of SLM practices, and also the costs and benefits associated with adopting SLM practices in Kinale-Kikuyu, Cherangani, and Wundanyi water catchments in Kenya. A multistage, probability proportional to size sampling method was used to select 388 households for a cross-sectional survey in the year 2015. The study used the World Overview of Conservation Agriculture Technologies survey tools in a mixed-methods research technique. Profitability analysis, return on investment, and sensitivity analyses were conducted. Terraces, infiltration ditches, and trash lines were popular practices adopted by farmers. The cost of establishing terraces on a hectare of land was US$445. The most expensive vegetative SLM practice, woodlot, costed US$ 534 per hectare to establish. Average yields increased by 49.8% in Kinale-Kikuyu, 60.6% in Cherangani, and 107.5% in Wundanyi due to adoption of SLM practices. Yield increases of 8.7% in fodder maize and 108% in tomatoes and potatoes were observed. The percentage increase in mean annual gross margins due to adopting SLM practices was highest in Wundanyi at 242.09%. Cost-benefit analysis showed that Kinale-Kikuyu had the highest Net Present Value of US$ 4083.73 due to adopting SLM. Positive Net Present Values were an indicator of the benefits of SLM in all the catchments. Benefits accruing from the adoption of SLM practices by the farmers exceeded the costs of establishing the SLM structures in the long run. It is recommended that a pilot Payment for Ecosystem Services (PES) project be established on hilly catchments and for linkages to be made between markets for produce and farmers willing to adopt SLM practices as an incentive to adopt them

Root-yield performance of pre-release sweet potato genotypes in Kenya

Objective: The focus of this study was to evaluate the yield and stability of superior sweet potato cultivars for release in Kenya. This is the first attempt to document experimental results that have led to the first and so far only sweet potato variety release in Kenya. Methodology: Ten national performance trials laid out as randomized complete block designs were performed on 14 sweet potato (Ipomoea batatas (L.) Lam.) genotypes in two geographical locations of Kenya. The trials were conducted to select local and introduced genotypes that were high yielding, stable, and tasty. Four experiments involving all the 14 genotypes were carried out in Nairobi while six experiments involving nine of the genotypes were carried out at three sites in Western Kenya. The stability of root yield and palatability test ranking were determined using appropriate statistical tools. Results: Significant (P = 0.05) differences in root yield between genotypes were observed for both locations. Mean root yield was higher in Nairobi (16,760 kg ha-1) than in Western Kenya (15,150 kg ha-1). The proportion of marketable roots was higher in Nairobi than in Western Kenya. Dry matter content was also higher in Nairobi (29.63%) than in Western Kenya (26.58%). Genotype x environment (G×E) interactions were significant (P = 0.05) in both locations. Conclusion and applications: Recommendations on the suitable varieties for official release are given. KEMB 10 and Mugande were the best performers in both environments. These two varieties contribute to enhancing food security among small scale household farmers in rural Kenya. Since its release in 2000, SPK 004 has contributed to enhancing the availability of the beta carotene micronutrient. Key Words: Environment, Genotype, Stability J. Appl. Biosci. 201

Master of Science in Rangeland Ecosystem Management Curriculum

The combination of inadequate understanding of the dynamics in rangeland ecosystems and local livelihood systems are to blame for the inappropriate policy actions, unabated rangeland degradation trends, impoverishment of communities living in the rangelands, and their increased vulnerability to various shocks including climate change. The root cause of these problems is mainly linked to lack of inadequate skilled human resources, trained in rangeland ecosystem management at the postgraduate level, to tackle the complex biodiversity interactions in the rangeland ecosystems. The philosophy of this degree programme is, therefore, anchored in the paradigm that rangelands are socio-ecological systems with complex biophysical, socio-cultural and economic interactions, which call for specialized managers and decision makers. This programme therefore, aims to produce a critical mass of rangeland ecosystem management experts equipped with requisite skills, technologies and innovations to further research, apply appropriate practices and influence policies in favour of resilient rangeland ecosystems and livelihoods. Trained skilled manpower is expected to act as a catalyst for enhancing the productivity and sustainability of rangeland ecosystems and livelihoods through practice, policies and research

Master of Science in Climate-Smart Agriculture Curriculum

Food production faces interlinked challenges with increasing uncertainties from the increasing impacts of climate change and variability. The underlying philosophy of CSA is the development and promotion of an integrative approach that results in landscape management for productive croplands, livestock, forests, and fisheries. It aims for improved food and nutrition security and equitable livelihoods. The program seeks to support the achievement of three outcomes i.e. increased productivity (producing more food to improve food, nutrition, and income security and livelihood of the world’s resource-poor farmers in rural areas); enhanced resilience (contributing to training for reduced vulnerability to drought, pests, disease, and other shocks); reduced emissions (reducing emissions from production systems to protect the environment while increasing productivity); and improved capacity to adapt (increasing productivity in the face of extreme climatic weather patterns). The program anchors on existing knowledge, technologies, and principles of sustainable agriculture. The need to increase carbon sinks and reduce GHGs emissions is a priority consideration, especially during training for a sustainable agro-ecosystem. Its design explicitly focuses on addressing productivity and climate change mitigation and adaptation with consideration of the interactions and tradeoffs existing between them. Finally, the CSA program aims to support funding opportunities for innovation and technology development for extension through research investment

Bachelor of Science in Rangeland Ecosystem Management Curriculum

The School of Agriculture, Earth and Environmental Sciences strongly believes in supporting advances in various aspects of rangeland science and community development practices in the rangeland ecosystem. There is increasing need to have well trained personnel with expertise in sustainable rangeland management, to provide leadership and stewardship for a sustainable framework for managing rangelands. This paradigm underlies the philosophy of linking the programme delivery with hands-on training, support to applied research and policy support ability to effectively contribute to sustainable rangeland ecosystem development and management. Universities have a key role in providing technical support in theory and practice by being proactive in training, research and innovation for sustainable rangeland resource management. This degree programme will contribute to the goal of improving the rangeland ecosystem health, while supporting sustainable livelihood options of communities and biodiversity in these ecosystems