Victor Mares

An integrated agro-ecosystem and livelihood systems approach for the poor and vulnerable in dry areas

More than 400 million people in the developing world depend on dryland agriculture for their livelihoods. Dryland agriculture involves a complex combination of productive components: staple crops, vegetables, livestock, trees and fish interacting principally with rangeland, cultivated areas and watercourses. Managing risk and enhancing productivity through diversification and sustainable intensification is critical to securing and improving rural livelihoods. The main biophysical constraints are natural resource limitations and degradation, particularly water scarcity and encroaching desertification. Social and economic limitations, such as poor access to markets and inputs, weak governance and lack of information about alternative production technologies also limit the options available to farmers. Past efforts to address these constraints by focusing on individual components have either not been successful or are now facing a declining rate of impact, indicating the need for new integrated approaches to research for development of dryland systems. This article outlines the characteristics of such an approach, integrating agro-ecosystem and livelihoods approaches and presents a range of empirical examples of its application in dryland contexts. The authors draw attention to new insights about the design of research required to accelerate impact by integrating across disciplines and scales.

Improving potato drought tolerance through the induction of long-term water stress memory

Knowledge of drought tolerance in potato is limited and very little is known about stress memory in this crop. In the present study, long-term stress memory was tested on tuber yield and drought tolerance related traits in three potato varieties (Unica, Désirée and Sarnav) with contrasted yields under water restriction. Seed tubers produced by plants grown under non-restricted (non-primed tubers) and restricted (primed tubers) water conditions were sown and exposed to similar watering treatments. Tuber yield and leaf greenness of plants from primed and non-primed seeds as well as tuber carbon isotope discrimination (Δ(13)C) and antioxidant activity (AA) responses to watering treatments were compared. Higher tuber yield, both under non-restricted and restricted water regimes, was produced by primed Sarnav plants. The decrease of tuber yield and Δ(13)C with water restriction was lower in primed Unica plants. Long-term stress memory consequently appears to be highly genotype-dependent in potato. Its expression in plants originated from primed tubers and facing water restriction seems to be positively associated to the degree of inherent capability of the cultivar to yield under water restriction. However, other effects of priming appear to be genotype-independent as priming enhanced the tuber AA in response to water restriction in the three varieties.

Detection of bacterial wilt infection caused by Ralstonia solanacearum in potato (Solanum tuberosum L.) through multifractal analysis applied to remotely sensed data

Potato bacterial wilt, caused by the bacterium Ralstonia solanacearum race 3 biovar 2 (R3bv2), affects potato production in several regions in the world. The disease becomes visually detectable when extensive damage to the crop has already occurred. Two greenhouse experiments were conducted to test the capability of a remote sensing diagnostic method supported by multispectral and multifractal analyses of the light reflectance signal, to detect physiological and morphological changes in plants caused by the infection. The analysis was carried out using the Wavelet Transform Modulus Maxima (WTMM) combined with the Multifractal (MF) analysis to assess the variability of high-resolution temporal and spatial signals and the conservative properties of the processes across temporal and spatial scales. The multispectral signal, enhanced by multifractal analysis, detected both symptomatic and latently infected plants, matching the results of ELISA laboratory assessment in 100 and 82%, respectively. Although the multispectral method provided no earlier detection than the visual assessment on symptomatic plants, the former was able to detect asymptomatic latent infection, showing a great potential as a monitoring tool for the control of bacterial wilt in potato crops. Applied to precision agriculture, this capability of the remote sensing diagnostic methodology would provide a more efficient control of the disease through an early and full spatial assessment of the health status of the crop and the prevention of spreading the disease.

Pursuing the Millennium Development Goals in the Andean Altiplano: Building on CIP Project Experience with Poverty Alleviation and Sustainable Development

Abstract The International Potato Center (CIP) has had an evolving research-for-development agenda that includes potatoes, sweet potatoes, Andean roots and tubers, and sustainable use of natural resources in mountains. In 2003, CIP completed a participatory Vision Exercise that led to prioritization of 7 development challenges that reflect 8 of the UN Millennium Development Goals (MDGs). In summary, these challenges include: reducing poverty and hunger; improving human health; developing sustainable rural and urban systems; and improving the availability of new technologies. A strategy was developed to help accomplish the selected MDGs. The first step towards implementation of this vision was a realignment of CIPs research program. Then, using different tools such as GIS and available national, regional, and world statistics, poverty targeting was carried out in order to prioritize the countries and regions where CIP will focus its resources and its research and development efforts. Targets were identified by overlaying poverty, hunger, and vulnerability with the areas where CIPs commodities are produced. Within this framework, the Center is implementing a new project in the Central Andes Altiplano, which is supported by the Government of Canada as well as other donors. The project is called ALTAGRO (Andean Agriculture in the Altiplano).

Improving potato cultivation using siphons for partial root-zone drying irrigation: a case study in the Blue Nile river basin, Ethiopia.

Abstract Partial root-zone drying (PRD) is an irrigation technique which consists of alternating the water supply from one furrow to another, and keeping the other one dry during the weekly alternation period. Studies assessing PRD in potato have reported a 30-50% of water savings with no tuber yield reductions and an increase of antioxidant concentrations and marketable tubers. In this study, we adapted the PRD technique to rural Ethiopian conditions and compared it against the customary (C) irrigation practiced by local farmers. Two PRD alternatives were evaluated; with (PRDs) and without (PRDw) locally made flexible-hose siphons. Only PRDs showed no significant differences in total (35.8±1.6 t ha-1) and marketable (34.2±1.6 t ha-1) tuber yield when compared with customary irrigation (39.4±1.3 and 37.6±1.2 t ha-1 corresponding to total and marketable yield, respectively). The PRDw was more water restricted, showing significantly lower total (29.7±1.1 t ha-1) and marketable (27.6±1.2 t ha-1) yields. PRDs had the benefit of a better control of applied water allowing a saving of 50% of the irrigation water without negatively affecting yield. The use of the siphons PRD technique provides options for saving scarce water and reaching out to many smallholder farmers who are in serious need of irrigation water in the Blue Nile river basin.

The Historical, Social, and Economic Importance of the Potato Crop

The potato has a fascinating history, from its origin and domestication in the Andean Region, where it was essential for feeding a growing population, for example, the Inca Empire, to its introduction into farming and food systems in Europe and elsewhere in the world. This crop has been the key factor in terms of food security, nutrition, population growth and urbanization in many regions. In recent decades, the potato has become a dominant crop in countries such as China and India, and its cropping area and production have increased more than those of any other food crop in Africa. Besides the social and economic importance of potato, extensively discussed in several published articles and briefly mentioned in this chapter, we discuss two relevant issues that are intimately related to potato genomics and breeding and which make potato a crop that has a lot to offer for the future. Those issues are the potato’s contribution to food and nutrition security, and the cultural and genetic importance of biodiversity conservation in the Andes; these issues are strongly related to gender, since women in traditional societies have contributed—and still contribute—to an enormous wealth of knowledge in relation to biodiversity conservation and utilization. The adaptability shown by the potato crop over thousands of years indicates the potential role of the potato as a climate-smart crop, particularly based on its short vegetative period, water utilization efficiency, and productive capacity per unit of input.

Impact of climate change on the potato crop and biodiversity in its center of origin

Abstract The Andean region is the most important center of potato diversity in the world. The global warming trend which has taken place since the 1950s, that is 2-3 times the reported global warming and the continuous presence of extreme events makes this region a live laboratory to study the impact of climate change. In this review, we first present the current knowledge on climate change in the Andes, as compared to changes in other mountain areas, and the globe in general. Then, the review describes the ecophysiological strategies to cope and adapt to changes in atmospheric CO2 levels, temperature and soil water availability. As climate change also has a significant effect on the magnitude and frequency of the incidence of pests and diseases, the current knowledge of the dynamics of vectors in the Andean region is discussed. The use of modeling techniques to describe changes in the range expansion and number of insect pest generations per year as affected by increases in temperature is also presented. Finally, the review deals with the use of crop modeling to analyze the likely impact of projected climate scenarios on potato yield and tuber initiation.

How big is the potato (Solanum tuberosum L.) yield gap in Sub-Saharan Africa and why? A participatory approach

Abstract According to potato experts from ten Sub-Saharan Africa (SSA) countries working together in a community of practice (CoP) over a 3-years period, potato farmers across SSA can increase their current annual production of 10.8 million metric tons by 140% if they had access to high quality seed along with improved management practices. This paper describes this innovative new methodology tested on potato for the first time, combining modelling and a comprehensive online survey through a CoP. The intent was to overcome the paucity of experimental information required for crop modelling. Researchers, whose data contributed to estimating model parameters, participated in the study using Solanum, a crop model developed by the International Potato Center (CIP). The first finding was that model parameters estimated through participatory modelling using experts’ knowledge were good approximations of those obtained experimentally. The estimated yield gap was 58 Mg ha-1, of which 35 corresponded to a research gap (potential yield minus research yield) and 24 to farmers’ gap (research yield minus farmer’s yield). Over a 6-month period, SurveyMonkey, a Web-based platform was used to assess yield gap drivers. The survey revealed that poor quality seed and bacterial wilt were the main yield gap drivers as perceived by survey respondents.