Seed maturation and drying in sweet corn (Zea mays L.) endosperm mutants

Incorporation of high sugar endosperm mutants into sweet corn genotypes has altered the carbohydrate composition of the resultant kernels which exhibit high post-harvest sugar retention and extended shelf life. However, acceptance of these genotypes has been limited because of problems associated with reductions in seed viability and seedling vigor and increased susceptibility to soil pathogens;The objective of this study was to characterize the physiological differences in seed viability and vigor associated with drying temperature and stage of maturity, and to determine the relationships between kernel soluble sugars during maturation and subsequent seed quality in sweet corn endosperm mutants;Seed of three genotypes, Jubilee (su), Sucro (sh2), and a genotype with the se gene, was harvested over a range of moisture contents during five harvests at 4-day intervals beginning 35 days after pollination. Ears were dried at 35, 40 and 45 C to 12% moisture. Seed viability was determined by the warm germination test, while the cold germination test, shoot to root ratio, and germination test after soaking seeds were used as indicators of vigor. Leachate conductivity was measured to indicate membrane integrity. Soluble sugars of embryos and endosperms obtained from fresh kernels at successive stages of maturity and from seed leachate, were separated by high performance liquid chromatography;Sweet corn seed exhibited a protracted period of high moisture retention throughout maturation. Seed moisture was poorly correlated with seed viability (r = -0.52) and seedling vigor (r = -0.46). Seedling vigor was more a function of genotype while seed viability varied with genotype, maturity, and drying temperatures. The se-genotype exhibited superior viability and vigor as compared with Jubilee and Sucro. Kernel maturity had less effect on electrolyte leakage than did drying temperature and genotype. Sucro exhibited the greatest rate of leakage when conductivity was read at 6, 12, and 24 h after soaking seeds. High seed quality was obtained when seed was dried at 35 C;The se-genotype exhibited the highest ratio of embryo sucrose to total sucrose and ratios of maltose and raffinose to sucrose. It is suggested that these ratios may play a role in membrane integrity during maturation drying and during imbibition and subsequent germination

A crowdsensing method for water resource monitoring in smart communities

Crowdsensing aims to empower a large group of individuals to collect large amounts of data using their mobile devices, with the goal of sharing the collected data. Existing crowdsensing studies do not consider all the activities and methods of the crowdsensing process and the key success factors related to the process. Nor do they investigate the profile and behaviour of potential participants. The aim of this study was to design a crowdsensing method for water resource monitoring in smart communities. This study opted for an exploratory study using the Engaged Scholarship approach, which allows the study of complex real-world problems based on the different perspectives of key stakeholders. The proposed Crowdsensing Method considers the social, technical and programme design components. The study proposes a programme design for the Crowdsensing Methodwhich is crowdsensing ReferenceFrameworkthat includes Crowdsensing Processwith key success factors and guidelines that should be considered in each phase of the process. The method also uses the Theory of Planned Behaviour (TPB) to investigate citizens’intention to participate in crowdsensing for water resource monitoring and explores their attitudes, norms and perceived behavioural control on these intentions. Understanding the profiles of potential participants can assist with designing crowdsensing systems with appropriate incentive mechanisms to achieve adequate user participation and good service quality. A survey was conducted to validate the theoretical TB model in a real-world context. Regression and correlation analyses demonstrated that the attitudes, norms and perceived behavioural control can be used to predict participants’ intention to participate in crowdsensing for water resource monitoring. The survey results assisted with the development of an Incentive Mechanism as part of the Crowdsensing Method. This mechanism incorporates recruitment and incentive policies, as well as guidelines derived from the literature review and extant system analysis. The policies, called the OverSensepolicies, provide guidance for recruitment and rewarding of participants using the popular Stackelberg technique. The policies were evaluated using simulation experiments with a data set provided by the case study, the Nelson Mandela Bay Municipality. The results of the simulation experiments illustrated that the OverSenserecruitmentpolicycan reduce the computing resources required for the recruitment of participants and that the recruitment policy performs better than random or naïve recruitment policies. The proposed Crowdsensing Method was evaluated using an ecosystem of success factors for mobile-based interventions identified in the literature and the Crowdsensing Method adhered to a majority (90%) of the success factors. This study also contributes information systems design theory by proposing several sets of guidelines for crowdsensing projects and the development of crowdsensing systems. This study fulfils an identified need to study the applicability of crowdsensing for water resource monitoring and explores how a crowdsensing method can create a smart community

e-adaptation to climate change in Malawi

An ICT-enhanced participatory radio campaign in Malawi shows that ICTs can be easily integrated into the lives and work of smallholder family farmer

Critical reflection on knowledge and narratives of conservation agriculture

In the context of contemporary concerns about climate change and food security, Conservation Agriculture (CA) has emerged as a well-supported and central component of the agricultural sector development strategy across sub-Saharan Africa, including in Zambia, which is the focus of this paper. A variety of narratives about the benefits of CA over conventional agricultural systems underpin endeavours towards ‘scaling up’ CA and increasing rates of adoption amongst smallholder farmers nationwide. However, there is a knowledge politics underlying the translation of a weak evidence base around CA into persuasive narratives and financial and political support. In this paper, we trace the evolution of five narratives around CA in Zambia in relation to changing political agendas and the involvement of new public and private sector actors, and review the development of evidence bases and knowledge that support and challenge each of these narratives. We discuss the potential to open up space within this knowledge politics to alternative narratives and the contestation of the pervasive CA scaling up agenda. Critical reflection is essential to ensure that national and local evidence is more effectively used to guide national climate and agricultural policy developments and international donor initiatives

Farmer experiences of Tiyeni’s ‘deep-bed farming’ conservation agriculture system in Malawi

In the context of increasing NGO interest in the capacity of conservation agriculture methods to support sustainable agriculture across sub-Saharan Africa, this paper explores the experiences of farmers (n = 111) adopting the Tiyeni NGO’s deep-bed farming (DBF) system in northern Malawi. The results of a field survey suggest that whilst DBF delivers significant livelihood benefits for farmers relative to traditional techniques (a factor arguably driving its rapid spontaneous adoption throughout the area), some asset-poor farmers are unable to sustain DBF due to its labor demands. We argue that to widen its beneficial impacts in a manner that can be sustained, there is a need for Tiyeni’s DBF to be less prescriptive and more adaptive to specific social-ecological contexts

Seed maturation and drying in sweet corn (Zea mays L.) endosperm mutants

Incorporation of high sugar endosperm mutants into sweet corn genotypes has altered the carbohydrate composition of the resultant kernels which exhibit high post-harvest sugar retention and extended shelf life. However, acceptance of these genotypes has been limited because of problems associated with reductions in seed viability and seedling vigor and increased susceptibility to soil pathogens;The objective of this study was to characterize the physiological differences in seed viability and vigor associated with drying temperature and stage of maturity, and to determine the relationships between kernel soluble sugars during maturation and subsequent seed quality in sweet corn endosperm mutants;Seed of three genotypes, Jubilee (su), Sucro (sh2), and a genotype with the se gene, was harvested over a range of moisture contents during five harvests at 4-day intervals beginning 35 days after pollination. Ears were dried at 35, 40 and 45 C to 12% moisture. Seed viability was determined by the warm germination test, while the cold germination test, shoot to root ratio, and germination test after soaking seeds were used as indicators of vigor. Leachate conductivity was measured to indicate membrane integrity. Soluble sugars of embryos and endosperms obtained from fresh kernels at successive stages of maturity and from seed leachate, were separated by high performance liquid chromatography;Sweet corn seed exhibited a protracted period of high moisture retention throughout maturation. Seed moisture was poorly correlated with seed viability (r = -0.52) and seedling vigor (r = -0.46). Seedling vigor was more a function of genotype while seed viability varied with genotype, maturity, and drying temperatures. The se-genotype exhibited superior viability and vigor as compared with Jubilee and Sucro. Kernel maturity had less effect on electrolyte leakage than did drying temperature and genotype. Sucro exhibited the greatest rate of leakage when conductivity was read at 6, 12, and 24 h after soaking seeds. High seed quality was obtained when seed was dried at 35 C;The se-genotype exhibited the highest ratio of embryo sucrose to total sucrose and ratios of maltose and raffinose to sucrose. It is suggested that these ratios may play a role in membrane integrity during maturation drying and during imbibition and subsequent germination.</p