International Maize and Wheat Improvement Center

About: International Maize and Wheat Improvement Center is a nonprofit organization based out in Texcoco, Mexico. It is known for research contribution in the topics: Population & Agriculture. The organization has 1976 authors who have published 4799 publications receiving 218390 citations.

Capturing farm diversity with hypothesis-based typologies : An innovative methodological framework for farming system typology development

Abstract: Creating typologies is a way to summarize the large heterogeneity of smallholder farming systems into a few farm types Various methods exist, commonly using statistical analysis, to create these typologies We demonstrate that the methodological decisions on data collection, variable selection, data-reduction and clustering techniques can bear a large impact on the typology results We illustrate the effects of analysing the diversity from different angles, using different typology objectives and different hypotheses, on typology creation by using an example from Zambia’s Eastern Province Five separate typologies were created with principal component analysis (PCA) and hierarchical clustering analysis (HCA), based on three different expert-informed hypotheses The greatest overlap between typologies was observed for the larger, wealthier farm types but for the remainder of the farms there were no clear overlaps between typologies Based on these results, we argue that the typology development should be guided by a hypothesis on the local agriculture features and the drivers and mechanisms of differentiation among farming systems, such as biophysical and socio-economic conditions That hypothesis is based both on the typology objective and on prior expert knowledge and theories of the farm diversity in the study area We present a methodological framework that aims to integrate participatory and statistical methods for hypothesis-based typology construction This is an iterative process whereby the results of the statistical analysis are compared with the reality of the target population as hypothesized by the local experts Using a well-defined hypothesis and the presented methodological framework, which consolidates the hypothesis through local expert knowledge for the creation of typologies, warrants development of less subjective and more contextualized quantitative farm typologies

Understanding adaptive capacity and capacity to innovate in social-ecological systems: Applying a gender lens.

Abstract: Development policy increasingly focuses on building capacities to respond to change (adaptation), and to drive change (innovation). Few studies, however, focus specifically on the social and gender differentiation of capacities to adapt and innovate. We address this gap using a qualitative study in three communities in Solomon Islands; a developing country, where rural livelihoods and well-being are tightly tied to agriculture and fisheries. We find the five dimensions of capacity to adapt and to innovate (i.e. assets, flexibility, learning, social organisation, agency) to be mutually dependant. For example, limits to education, physical mobility and agency meant that women and youth, particularly, felt it was difficult to establish relations with external agencies to access technical support or new information important for innovating or adapting. Willingness to bear risk and to challenge social norms hindered both women’s and men’s capacity to innovate, albeit to differing degrees. Our findings are of value to those aspiring for equitable improvements to well-being within dynamic and diverse social–ecological systems.

Formation of Heterotic Groups and Understanding Genetic Effects in a Provitamin A Biofortified Maize Breeding Program

Abstract: Developing biofortified maize ( Zea mays L.) cultivars is a viable approach to combating the wide spread problem of vitamin A deficiency among people for whom maize is a staple food. To enhance CIMMYT’s provitamin A maize breed ing efforts, this study: (i) evaluated whether sep aration of experimental maize lines into groups based on maximizing their molecular-markerbased genetic distances (GD) resulted in het erosis for among-group crosses, (ii) assessed genetic effects (general and specific combining ability, GCA and SCA) for grain yield and provita min A concentrations in hybrids among 21 inbred lines representing the three proposed groups, and (iii) assessed the association between grain yield and provitamin A concentrations. The lines were crossed following a partial diallel design resulting in 156 hybrids that were evaluated at four environments with two replications of onerow plots. The first plant in each plot was selfpollinated to produce grain for provitamin A analysis. Significant but small yield advantage of among- versus within-group crosses (0.47 Mg ha -1 , P < 0.05) suggested that the groups identi fied by maximizing GD could be a practical start ing point for further breeding work to develop useful heterotic groups. Furthermore, the GDproposed heterotic groups were improved by later revising some line assignments to groups using estimates of SCA effects. General com bining ability effects were significant (P < 0.01) for all traits, whereas SCA effects were weak ( P < 0.05) or not significant for provitamin A carot enoid concentrations, indicating that these were controlled primarily by additive gene action. Grain yield was not significantly correlated with provitamin A concentration, indicating that both traits could be improved simultaneously.