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In-situ conservationTwo types of in-situ conservation of crop genetic resources can be distinguished: farmer-driven andexternally driven. The first is subject of this thesis and refers to the persistence of potato genetic resourcesin areas where everyday practices of farmers maintain diversity on-farm. The second concerns the morerecent phenomenon of Research & Development (R&D) interventions which aim to support in-situconservation by farmers. In this study, farmer-driven in-situ conservation of the potato in the central Andesof Peru is investigated at different system levels from alleles, cultivars, and botanical species up to the levelof the landscape, as well as the interconnected seed and food systems. Dimensions of time and space areinferred upon by taking both annual and longer-term spatial patterns into account. Further, diversity islinked to selected farmer-based and external drivers.Objective and study areaThe overall objective of the study is to enhance our understanding of farmer-driven in-situ conservationand the context in which it takes place. The main field research was conducted between 2003 and 2006 ineight farmer communities following a north-south transect through the department of Huancavelica.Communities were selected on the basis of distribution and distance along the north-south transect,tradition of potato cultivation, ethnicity, and relative distance from major markets or cities. Depending onthe specific dimension of farmer-driven in-situ conservation investigated, a range of different methodsand tools were used. Chapter 1 provides a brief description of the study area and an overview of the researchmethods used.Species, cultivar and allelic diversityIn chapter 2 the species, morphological and molecular diversity of Andean potatoes in Huancavelica istreated at different scales of conservation: farmer family, community, geographically distanced, regional,in-situ and ex-situ subpopulations. The infraspecific diversity of in-situ collections w

Las nuevas variedades de papa que se ofrecen a los agricultores deben tener ventajas intrínsecas, las mismas que deben ser superiores a las variedades existentes de uso tradicional. Esta variedad fue desarrollada por la División de Mejoramiento y Utilización de Recursos Genéticos del Centro Internacional de la Papa (CIP), con la colaboración de sus diferentes socios nacionales, entre los que destacan la Universidad Nacional San Luis Gonzaga de Ica, Perú. La reciente inscripción de la variedad UNICA en el Registro Nacional de Variedades Comerciales en el Servicio Nacional de Sanidad Agraria (SENASA), Perú; pone a disposición de los agricultores material genético, a partir de los sistemas formales de producción de semillas. Entre sus principales atributos resaltan la resistencia a virus (PVY), su tolerancia al calor, su moderada resistencia al nematodo del nudo (Meloidogyne ssp.), su precocidad, su estabilidad de rendimiento en varias épocas de siembra y su leve tolerancia a sales. En los últimos años a presentado un incremento de la oferta en los mercados de papa fresca y un posicionamiento en los mismos, debido a un mayor nivel de adopción entre los agricultores peruanos.

Las nuevas variedades de papa que se ofrecen a los agricultores deben tener ventajas intrínsecas, las mismas que deben ser superiores a las variedades existentes de uso tradicional. Esta variedad fue desarrollada por la División de Mejoramiento y Utilización de Recursos Genéticos del Centro Internacional de la Papa (CIP), con la colaboración de sus diferentes socios nacionales, entre los que destacan la Universidad Nacional San Luis Gonzaga de Ica, Perú. La reciente inscripción de la variedad UNICA en el Registro Nacional de Variedades Comerciales en el Servicio Nacional de Sanidad Agraria (SENASA), Perú; pone a disposición de los agricultores material genético, a partir de los sistemas formales de producción de semillas. Entre sus principales atributos resaltan la resistencia a virus (PVY), su tolerancia al calor, su moderada resistencia al nematodo del nudo (Meloidogyne ssp.), su precocidad, su estabilidad de rendimiento en varias épocas de siembra y su leve tolerancia a sales. En los últimos años a presentado un incremento de la oferta en los mercados de papa fresca y un posicionamiento en los mismos, debido a un mayor nivel de adopción entre los agricultores peruanos.

In this study, genotype by environment (G x E) interactions and phenotypic stability of resistance to Phytophthora infestans, the cause of late blight, were analysed in Peru lot 13 potato genotypes, using additive main effects and multiplicative interaction (AMMI) analysis and Huehn's non-parametric test. The potato genotypes were tested in seven experiments over two years in the vicinity of Comas, Peru, an area used by the International potato Center to screen for resistance to late blight. Results of the two analyses generally correlated and indicated that quantitative resistance to P. infestans was stable under field conditions for all the genotypes tested. The first two principal components (PCA1 and PCA2) of the AMMI analysis explained 54%. of the G x E interaction sum of squares. A biplot of the two principal components demonstrated a strong year effect in the G x E interaction. By plotting yearly means of the relative area under the disease progress curve (rAUDPC), genotypes could be assigned to one of three resistance categories, resistant, moderately resistant or Susceptible, but the need for a more readily applicable and truly quantitative scale for resistance was noted. Based on these studies, standards can be selected for use in screening in the area where they were tested. After further testing in other locations, a standard set drawn from these genotypes Could be identified and a quantitative scale developed for evaluation of resistance under short day conditions.

In this study, genotype by environment (G x E) interactions and phenotypic stability of resistance to Phytophthora infestans, the cause of late blight, were analysed in Peru lot 13 potato genotypes, using additive main effects and multiplicative interaction (AMMI) analysis and Huehn's non-parametric test. The potato genotypes were tested in seven experiments over two years in the vicinity of Comas, Peru, an area used by the International potato Center to screen for resistance to late blight. Results of the two analyses generally correlated and indicated that quantitative resistance to P. infestans was stable under field conditions for all the genotypes tested. The first two principal components (PCA1 and PCA2) of the AMMI analysis explained 54%. of the G x E interaction sum of squares. A biplot of the two principal components demonstrated a strong year effect in the G x E interaction. By plotting yearly means of the relative area under the disease progress curve (rAUDPC), genotypes could be assigned to one of three resistance categories, resistant, moderately resistant or Susceptible, but the need for a more readily applicable and truly quantitative scale for resistance was noted. Based on these studies, standards can be selected for use in screening in the area where they were tested. After further testing in other locations, a standard set drawn from these genotypes Could be identified and a quantitative scale developed for evaluation of resistance under short day conditions.

In this study, genotype by environment (G x E) interactions and phenotypic stability of resistance to Phytophthora infestans, the cause of late blight, were analysed in Peru lot 13 potato genotypes, using additive main effects and multiplicative interaction (AMMI) analysis and Huehn's non-parametric test. The potato genotypes were tested in seven experiments over two years in the vicinity of Comas, Peru, an area used by the International potato Center to screen for resistance to late blight. Results of the two analyses generally correlated and indicated that quantitative resistance to P. infestans was stable under field conditions for all the genotypes tested. The first two principal components (PCA1 and PCA2) of the AMMI analysis explained 54%. of the G x E interaction sum of squares. A biplot of the two principal components demonstrated a strong year effect in the G x E interaction. By plotting yearly means of the relative area under the disease progress curve (rAUDPC), genotypes could be assigned to one of three resistance categories, resistant, moderately resistant or Susceptible, but the need for a more readily applicable and truly quantitative scale for resistance was noted. Based on these studies, standards can be selected for use in screening in the area where they were tested. After further testing in other locations, a standard set drawn from these genotypes Could be identified and a quantitative scale developed for evaluation of resistance under short day conditions.

In this study, genotype by environment (G x E) interactions and phenotypic stability of resistance to Phytophthora infestans, the cause of late blight, were analysed in Peru lot 13 potato genotypes, using additive main effects and multiplicative interaction (AMMI) analysis and Huehn's non-parametric test. The potato genotypes were tested in seven experiments over two years in the vicinity of Comas, Peru, an area used by the International potato Center to screen for resistance to late blight. Results of the two analyses generally correlated and indicated that quantitative resistance to P. infestans was stable under field conditions for all the genotypes tested. The first two principal components (PCA1 and PCA2) of the AMMI analysis explained 54%. of the G x E interaction sum of squares. A biplot of the two principal components demonstrated a strong year effect in the G x E interaction. By plotting yearly means of the relative area under the disease progress curve (rAUDPC), genotypes could be assigned to one of three resistance categories, resistant, moderately resistant or Susceptible, but the need for a more readily applicable and truly quantitative scale for resistance was noted. Based on these studies, standards can be selected for use in screening in the area where they were tested. After further testing in other locations, a standard set drawn from these genotypes Could be identified and a quantitative scale developed for evaluation of resistance under short day conditions.