Daniela Soleri

Morphological and phenological comparisons of two Hopi maize varieties conserved in situ and ex situ

Over the last twenty-five years, crop genetic resources (CGR) have been preserved in genebanks around the world for use by formal plant breeders. Recently conservation of folk crop varieties for direct use by the farmer-breeders of traditional agricultural communities has been suggested as another purpose for CGR conservation. While both in and ex situ CGR conservation programs have been proposed to meet the needs of formal plant breeders and farming communities, the needs and goals of the two groups are different. Formal breeders seek maximum allelic diversity while farmer-breeders are interested in both diversity and population structure that provide local adaptation. Based on the morphological and phenological data analyzed for this study of two Hopi maize varieties conserved in and ex situ, it appears that both genetic shift and genetic drift have occurred ex situ, and that populations conserved ex situ are different from those maintained in situ. These findings suggest that CGR conservation strategies must be re-evaluated in light of the specific conservation goals that are sought.RésuméDurante los pasados veinticinco años, los recursos geneticos agricolas (RGA) han sido preservados en bancos de germoplasma alrededor del mundo para su uso por fitomejadores formates. Recientamente, la conservacion de variedades crillolaspara su uso directo por agricultores-fitomejsdores de las comunidades agricolas tradicionales se ha sugerido como otro de los propositos para la conservacion de recursos geneticos. Mientras que los programas de conservacion de RGA in situ y ex situ han sido propuestos para satisfacer las necesidades de fitomejoradores formales y cominidades agricolas, las necesidades y objetivos de los dos grupos son diferentes. Los fitomejoradores formales buscan la maxima diversidad genetica, mientras que los agricultores-fitomejoradores estan interesados en diversidad y estructura poblacionalque permita mayor adaptacion local. En bas a datos morfologicos y fenologicos analizados en este estudio de dos variedades de maiz Hopi conservadas in situ y ex situ, al parecer, la conservacion ex situ ha producido seleccion natural (genetic shift) y perdida aleatoria de diversidad (genetic drift), asimismo, parece que la poblaciones conservadas ex situ difieren de las conservadas in situ. Estos resultados sugieren que las estrategias para las conservacion de RGA deben ser reevaluadas conforme a los propositos especificos de conservacion.

A biological framework for understanding farmers’ plant breeding

We present a framework for understanding farmer plant breeding (including both choice of varieties and populations and plant selection) in terms of the basic biological model of scientific plant breeding, focusing on three key components of that model: 1) genetic variation, 2) environmental variation and variation of genotype-by-environment interaction, and 3) plant selection. For each of these concepts we suggest questions for research on farmers’plant breeding (farmers’ knowledge, practice, and crop varieties and growing environments). A sample of recent research shows a range of explicit and implicit answers to these questions which are often contradictory, suggesting that generalizations based on experience with specific varieties, environments or farmers may not be valid. They also suggest that farmers’ practice reflects an understanding of their crop varieties and populations that is in many ways fundamentally similar to that of plant breeders; yet, is also different, in part because the details of their experiences are different. Further research based on this framework should be valuable for participatory or collaborative plant breeding that is currently being proposed to reunite farmer and scientific plant breeding.ResumenSe presenta un marco teórico para un mas claro entendimiento del fitomejoramiento de los agricultores (se incluye tanto la selección o identification de variedades, poblaciones, o plantas individuales) desde la óptica de un modelo biológico básico. Dicho modelo trata 1) la variatión genética 2) la variatión ambiental, la variatión de la interación genotipo-ambiente y 3) la selección de plantas. Para coda uno de los conceptos anteriormente expresados se sugieren preguntas para investigar el fitomejoramiento de los agricultures (conocimiento de los agricultures, práctica, variedades de cultiva y sus ambientes). Una muestra de la reciente investigation demostró un rango de implicitas y explicitas respuestas para las preguntas formuladas, las cuales son en ocasiones contradictorias, lo que sugiere que la generalizatión de las experiencias basada con específicas variedades, ambientes o agricultures pudieran no ser válida. Se plantea que las prácticas de los campesinos reflejan un entendimiento de sus variedades y poblaciones que tienen en parte cierta similitud con los fitomejoreadores convencionales, aunque en parte es tambien diferente ya que los detalles de las experiencias de agricultures y fitomejoradores convencionales son distintas. Otras investigations basados en este marco pudieran contribuir al fitomejoramiento colaborativo o participativo, lo cual actualmente ha sido propuesto para reunificar a los agricultures y los cientificos del fitomejoramiento de plantas.

Farmers’ genetic perceptions regarding their crop populations: An example with maize in the central valleys of Oaxaca, Mexico

Collaborative plant breeding is an approach to crop improvement that includes close attention to specific adaptation and interaction between farmers and formal plant breeders to better meet the needs of those farmers. Collegial interaction capable of making best use of the knowledge and skills of farmers and breeders will depend upon an understanding of those in terms that are relevant to each. To facilitate this interaction with the goal of making farmer selection practices more effective, the work described here sought to improve outside researchers’ understanding of farmers’ fundamental perceptions about their populations, growing environments, and expectations for response to selection. Various methods were used to accomplish this with a small sample of maize farmers in two communities in the Central Valleys of Oaxaca, Mexico. Farmers’ decisions about maize varietal type repertoires imply assessments based on genetic and environmental variation in the local context. A clear distinction was made between traits of high and low heritability and expected response to selection, however, some traits of interest to farmers such as large seed size may involve considerations other than their potential for expression in the progeny generation.ResumenEl fitomejoramiento colaborativo es una forma de mejora de las plantas, que presta especial atención, a la adaptatión especifica y la interactión entre agricultores y fitomejoradores para un mejor respuesta a las necesidades de los primeros. Lo que facilita la interaction entre agricultores y fitomejoradores, pretendiendo que la selection de los agricultores sea mas eficiente. El trabajo describe una via para el mejor entendimiento de los investigadores en relation a las percepciones fundamentals de los agricultores respecto a sus poblaciones cultivadas, sus ambientes de cultivo y sus expec-tativas en relation con la respuesta a la selection. Varios metodos fueron aplicados a una pequena muestra de agricultores en dos comunidades en los Valles Centrales de Oaxaca, Mexico, ha decision de los agricultores de escoger sus variedades esta basada en la variatón genetica y ambiental a nivel local. Una clara distinción fue hecha por los agricultores entre los caracteres de alta y baja heredabilidad así como la respuesta a la selection; pero, los resultados sugieren que algunos caracteres de interés para los agricultores como el tamaño del grano son importantes como criterio de selection, aun cuando no lo asocian con un efecto genético.

Extending Darwin's Analogy: Bridging Differences in Concepts of Selection between Farmers, Biologists, and Plant Breeders

Darwin developed his theory of evolution based on an analogy between artificial selection by breeders of his day and “natural selection.” For Darwin, selection included what biologists came to see as being composed of (1) phenotypic selection of individuals based on phenotypic differences, and, when these are based on heritable genotypic differences, (2) genetic response between generations, which can result in (3) evolution (cumulative directional genetic response over generations). The use of the term “selection” in biology and plant breeding today reflects Darwin’s assumption—phenotypic selection is only biologically significant when it results in evolution. In contrast, research shows that small-scale, traditionally-based farmers select seed as part of an integrated production and consumption system in which selection is often not part of an evolutionary process, but is still useful to farmers. Extending Darwin’s analogy to farmers can facilitate communication between farmers, biologists, and plant breeders to improve selection and crop genetic resource conservation.

Understanding farmers' knowledge as the basis for collaboration with plant breeders: methodological development and examples from ongoing research in Mexico, Syria, Cuba and Nepal.

There has been very little comparative research on farmers’ and scientists’ theoretical or conceptual knowledge, sometimes leading to reliance on untested assumptions in plant breeding projects that attempt to work with farmers. We propose an alternative approach that is inductive, based on a very basic biological model of plant–environment relationships, and on a holistic model of knowledge. The method we use was developed in Oaxaca, Mexico, and is based on scenarios involving genotype × environment interactions, heritability, and genetic response to selection. It is being modified and applied in a research project with collaborating scientists and farmers in Syria (barley), CAB International 2002. Farmers, Scientists and Plant Breeding (eds D.A. Cleveland and D. Soleri) 19

Molecular characterization of genetic diversity, structure, and differentiation in the olive (Olea europaea L.) germplasm collection of the United States Department of Agriculture

Fifteen microsatellite loci were used to genotype 108 accessions of cultivated olive, Olea europaea L. ssp. europaea var. europaea, and eight of O. europaea L. ssp. cuspidata (Wall. ex G. Don) Ciferri, from the germplasm collection of the United States Department of Agriculture in Davis, California. Number of alleles per locus ranged from 3, for locus IAS-pOe12_A, to 16, for locus ssrOeUA-DCA11, with an overall mean of 9.93. Observed heterozygosity ranged from 0.175, for locus UDO99–019, to 0.937, for locus GAPU89, with a mean of 0.640. The cluster analysis using the Unweighted Pair Group Method using Arithmetic mean (UPGMA) method displayed thirteen clusters within seven main groups that can be partially described by common geographic origin or fruit use, though overlap among these groups was common. The locus-wise total gene diversity (HT) ranged from 0.319, at UDO99–019, to 0.847, at ssrOeUA-DCA3, with an overall mean of 0.696. Most of the gene diversity was partitioned within clusters, with proportions (HS/HT) ranging from 0.633, at IAS-pOe12_B, to 0.848 at GAPU89 per locus, with a mean of 0.759. The principal components analysis explained 24.8% of the total variation along the first two components. Projection of accessions onto the first two principal components produced affinities generally in agreement with the results of the UPGMA cluster analysis. The California cultivar ‘Mission’ clustered closely with Iberian cultivars and may represent clonal selections adapted to local growing conditions. The results show significant diversity but low levels of differentiation among olive cultivars within the collection.

Rethinking the Risk Management Process for Genetically Engineered Crop Varieties in Small-scale, Traditionally Based Agriculture

Proponents of genetically engineered (GE) crops often assume that the risk management used in the industrial world is appropriate for small-scale, traditionally based agriculture in the Third World. Opponents of GE crops often assume that risk management is inappropriate for the Third World, because it is inherently biased in favor of the industrial world. We examine both of these assumptions, by rethinking risk management for GE crops and transgenes, using the example of maize transgene flow from the U.S. to Mexico. Risk management for the Third World is a necessary first step of a broader benefit–cost analysis of GE crops, which would include comparisons with existing varieties and with alternative varieties such as transgenic farmer varieties and organic varieties. Our goal is to use existing information on GE crops and on the social and biological characteristics of Third World agriculture to identify key processes that need to be considered in risk management, and the additional research required to adequately understand them. The four main steps in risk management are hazard identification, risk analysis (exposure x harm), risk evaluation, and risk treatment. We use informal event trees to identify possible exposure to GE crops and transgenes, and resulting biological and social harm; give examples of farmers’ ability to evaluate social harm; and discuss the possibilities for risk treatment. We conclude that risk management is relevant for Third World agriculture, but needs to be based on the unique biological and social characteristics of small-scale, traditionally based agriculture, including the knowledge and values of Third World farmers and consumers.

Scenarios as a Tool for Eliciting and Understanding Farmers’ Biological Knowledge

Modern scientific knowledge and indigenous or traditionally based knowledge are often assumed to be fundamentally different and incomparable. Testing this assumption is important theoretically and for supporting scientist-farmer collaboration to improve farmers’ well-being in their own terms. We illustrate the use of scenarios based on a basic biological model to understand farmers’ theoretical biological knowledge. Scenarios depict aspects of the model in terms comprehensible to farmers and relevant to collaboration with scientific plant breeders. Results suggest that scenarios are useful for eliciting traditionally based biological knowledge and that farmers’ theoretical biological knowledge is based on the same model as that of scientists.

Collaborative Plant Breeding as an Incentive for On-Farm Conservation of Genetic Resources: Economic Issues from Studies in Mexico

One characteristic of classical crop improvement and genetic resource conservation programs is their physical and temporal distance from one another as well as from the farmers who are their clients. Genetic resources in breeders’ working collections or conserved ex situ in gene banks are used in crosses, and selection in segregating populations is carried out under experimental conditions. The resulting varieties or advanced lines are eventually tested in a range of sites, but often testing does not include the fields of farmers, especially small-scale farmers in environments beset by biotic and abiotic stresses. The finished products are released after years of research and intended for use over extensive geographical areas.

Farmers’ Varietal Identification in a Reference Sample of Local Phaseolus Species in the Sierra Juárez, Oaxaca, Mexico

Farmers’ Varietal Identification in a Reference Sample of LocalPhaseolusSpecies in the Sierra Juárez, Oaxaca, Mexico. Farmer-named varieties are often the basis of in situ diversity assessment, collections for ex situ conservation, and on-farm improvement programs. Such varieties play an important role in sustainable agriculture because of their adaptation to local environmental conditions and consumer tastes. The importance of these varieties has stimulated interest in understanding farmers’ varietal classifications. We investigated the empirical basis of, and agreement among, farmers’ bean variety classification in a community in the Sierra Juárez, Oaxaca, Mexico. A reference sample of 300 local seeds of three Phaseolus species was sorted by nine farmers into named varieties. Nuclear and chloroplast microsatellite markers and seed morphology data were used to a) establish species identities; and test the hypotheses that b) farmer varieties reflect morphological and genetic structures; and c) there is agreement among farmers in variety classification. Because all farmers sorted the same set of seeds the variation in individual farmers’ classifications could be documented and compared. Our results indicate an empirical basis for farmer varieties, but without stringent classification rules. Varietal names underestimated diversity present at the community level because of the intravarietal variation present in farmer classifications. There was low classification agreement among farmers, although broad morphological and genetic patterns were present. The variation in farmers’ classifications of this Phaseolus diversity resulted in both synonymy and homonymy across classifications. The goal of farmers may not be to maintain the same variety across households, but to form a version of a broad type that best fits their own needs and circumstances at one point in space and time. Thus, in both work with farmers and collections of their Phaseolus varieties for ex situ conservation it should not be assumed that same-named seed lots are redundant units of diversity. Morphological and/or molecular data should, therefore, supplement farmer varietal names in assessments of in situ crop diversity, while ex situ collections would benefit from the inclusion of multiple accessions of the same variety from different farmers, repeated over time.Identificación campesina de variedades en una muestra de referencia de especies locales de Phaseolusen la Sierra Juárez, Oaxaca, México. Los nombres locales de las variedades ofrecidos por los agricultores son, a menudo, la base para la determinación de diversidad in situ, las colecciones para la conservación ex situ, y para los programas de mejoramiento participativo. Tales variedades juegan un papel importante en la agricultura sostenible debido a su adaptación a las condiciones ambientales locales y los gustos de los consumidores. La importancia de estas variedades ha estimulado el interés en comprender los principios clasificatorios de los agricultores. Nosotros investigamos los principios empíricos y el grado de acuerdo sobre la clasificación de frijoles entre los agricultores de la Sierra Juárez, Oaxaca, México. Una muestra de referencia de 300 semillas locales de tres especies de Phaseolus fue clasificada por nueve agricultores en variedades con nombres locales. Morfología de las semillas y marcadores moleculares del núcleo y de lo cloroplasto fueron utilizados para: a) establecer las identidades de las especies; y para probar las hipótesis: b) que variedades identificadas por los campesinos reflejan estructuras morfológicas y genéticas; y c) que existe concordancia entre los agricultores en cuanto a la identificación de las variedades. Debido a que los agricultores clasificaron el mismo conjunto de semillas, la variación entre las clasificaciones de los agricultores como individuos pudo ser documentada y comparada. Nuestros resultados indican que hay una base empírica de la identificación campesina de las variedades, pero sin reglas clasificatorias estrictas. Los nombres de las variedades subestiman la diversidad existente en la comunidad debido a la inconsistencia presente entre las clasificaciones de los agricultores. Hubo un bajo grado de concordancia entre los agricultores, aunque pautas morfológicas y genéticas generales fueron presentes. La variación entre las clasificaciones campesinas de esta diversidad de Phaseolus resultó tanto en la sinonimia como homonimia entre las clasificaciones. Es posible que la meta de los agricultores no sea mantener la misma variedad de fijol entre granja y granja, sino de un tipo general formar una version que mejor responda a sus propios intereses y circunstancias en el espacio y el tiempo. Así, tanto en el trabajo con los agricultores y en la colección de sus variedades de Phaseolus para conservación ex situ, no debe asumirse que los lotes con el mismo nombre sean unidades redundantes de diversidad. Los datos morfológicos y/o moleculares deben, por consiguiente, complementar los nombres que proporcionan los agricultores en la determinación de la diversidad in situ, mientras que las colecciones ex situ podrían beneficiarse de la inclusión de accesiones múltiples de la misma variedad, pero de distintos agricultores, repetidas a lo largo del tiempo.