Sandra E. Vega

Assessing changes in the genetic diversity of potato gene banks. 2. In situ vs ex situ

Abstract An important question in the conservation of potato germ plasm is whether germ plasm in the gene bank, although stable, still represents the in situ populations from which it was collected, sometimes many decades ago. The answer would direct objective decisions regarding the value of re-collections and in situ preservation. The present study was undertaken as a project of the Association of Potato Inter-gene-bank Collaborators (APIC). It measured genetic differentiation between potato germ plasm maintained in the US gene bank for many years and current in situ populations re-collected from the same original sites in the wild. Solanum jamesii and Solanum  fendleri from the United States were used as representatives of potato germ plasm. Re-collections were carried out in 1992 at the same locations at which gene bank-conserved accessions had been collected in 1958 and 1978. RAPD markers revealed significant genetic differences between gene bank-conserved and re-collected in situ populations for all seven comparisons of S. jamesii (diploid outcrosser), and 12 of 16 comparisons within S.  fendleri (tetraploid inbreeder). The average genetic similarities were 65.2% for S.  jamesii and 80.4% for S.  fendleri. Possible explanations and consequences of these unexpectedly large differences are discussed.

Evidence for the up-regulation of stearoyl-ACP (Δ9) desaturase gene expression during cold acclimation

Our previous studies demonstrated that an increase in 18:2 (linoleate) in the purified plasma membrane fraction during cold acclimation is associated with genetic variations in cold acclimation capacity. This increase was found only in genotypes that are able to cold acclimate and was reversible on deacclimation suggesting a link between the accumulation of 18:2 and acquisition of freezing tolerance. The present study was aimed at understanding the association between the induction of stearoyl-ACP (acyl carrier protein) (Δ9) desaturase and the ability to cold acclimate. Our approach was to study the induction of Δ9 desaturase at the transcript level using potato Δ9 desaturase gene-specific primers and reverse transcription polymerase chain reaction (RT-PCR). For this purpose, total RNA fromSolanum tuberosum (cold sensitive, unable to acclimate) andSolanum commersonii (cold tolerant, able to cold acclimate) was extracted before and after cold acclimation. RT-PCR produced a single band and sequence analysis confirmed that the amplified band was Δ9 desaturase. While the cold acclimating species,Solanum commersonii, exhibited an increase in Δ9 desaturase transcript levels after cold acclimation, the cold non-acclimating species,Solanum tuberosum, exhibited no change. Our results show that the increase in Δ9 desaturase gene transcripts during cold acclimation is associated with the cold acclimation response in potato.ResumenEstudios realizados en nuestro laboratorio han demostrado que durante la acclimatación a bajas temperaturas existe un incremento del ácido linoleico (18:2) en la membrana plasmática. Dicho incremento está asociado con la variación genética observada en la capacidad de aclimatación en papa. Este incremento fue encontrado únicamente en los genotipos capaces de aclimatarse y fue reversible durante la deaclimatacion sugiriendo que existe una relacion entre acumulación de 18:2 y adquisición de resistencia a bajas temperaturas. El presente trabajo tuvo como objetivo estudiar la asociación entre la inducción de la desaturasa stearoyl-ACP (proteina portadora de acyl) (Δ9) y la habilidad de aclimatarse a bajas temperaturas. Para ello se estudió la inducción de la desaturasa Δ9 a nivel the transcripción utilizando primers especificos para el gen de desaturasa de papa mediante reacción de polimerasa en cadena de transcripción reversa (RT-PCR). Se extrajo el ARN total deSolanum tuberosum (sensible a heladas, incapaz de aclimatarse a bajas temperaturas) ySolanum commersonii (resistente a heladas, capaz de aclimatarse a bajas temperaturas) antes y después del proceso de aclimatación. RT-PCR produjo una sohl banda y el análisis de la secuencia confirmó que la banda amplificada era desaturasa Δ9. Mientras que la especie capaz de aclimatarse,Solanum commersonii, exhibió un incremento en los niveles de transcripción de la desaturasa Δ9 después de la aclimatación, la especie incapaz de aclimatarse,Solanum tuberosum, no exhibió ningún cambio. Nuestros resultados demuestran que el incremento en la transcripción del gen de desaturasa Δ9 durante la aclimatación a bajas temperaturas está asociado con la capacidad de aclimatación a bajas temperaturas en papa.

Screening the U.S. potato collection for frost hardiness

Potato is one of the most important world vegetables with respect to value of production and nutritional impact. Frost susceptibility reduces or precludes production on millions of hectares worldwide. In contrast to disease and pest problems, cultural or chemical treatments are not likely to be helpful in combating frost, so genetic improvement must be sought. Fortunately, wild relatives of the cultivated potato have been shown to exhibit frost tolerance far superior to that of cultivated species. In this research, over 2,600 accessions representing 101 species in the US potato collection at Sturgeon Bay, Wisconsin were visually screened after natural frosts in a uniform field in 1992. This provided a more comprehensive survey of germplasm accessions, further characterized species’ hardiness and intraspecific variation. The most hardy species wereSolanum acaule, S. albicans, S. commersonii, andS. demissum. An additional previously unreported extremely frost hardy species (Solanum paucissectum) was discovered. This information should expand the insights and germplasm options available to those intent on breeding desirable varieties with high levels of frost hardiness.CompendioLa papa es uno de los cultivos más importantes en el mundo con respecto a su valor productivo y de consumo. La sensibilidad a heladas reduce o afecta la producción de papa en millones de hectáreas a nivel mundial. A diferencia de otras enfermedades o pestes, las prácticas de cultivo o los tratamientos químicos no son efectivos en combatir heladas. En consecuencia, el mejoramiento genético es necesario. Afortunadamente, las especies silvestres de papa han demostrado tener mucho mayor tolerancia a heladas que las especies cultivadas. En la presente investigación, más de 2,600 accesiones representando 101 especies de la colección de papa de Estados Unidos mantenida en Sturgeon Bay — Wisconsin fueron evaluadas en el campo en 1992. Esta evaluación ofrece una información más detallada sobre un gran número de accesiones con respecto a la resistencia a heladas y la variación intra-específica que existe. Las especies más resistentes a heladas fueron Solanum acaule, S. albicans, S. commersonii, and S. demissum. Además el présente estudio identifica una especie (Solanum paucissectum) resistente a heladas que no ha sido reportada anteriormente. Esta información amplía las opciones actualmente existentes para aquellos interesados en el mejoramiento de variedades con resistencia a heladas.

Identification and Selection for Tuber Calcium, Internal Quality and Pitted Scab in Segregating ‘Atlantic’ x ‘Superior’ Reciprocal Tetraploid Populations

Developing chipping cultivars with improved tuber quality and disease resistance is a major interest for breeders and the potato industry. A popular chipping cultivar ‘Atlantic’, is desired for its high yield and gravity. However, this cultivar suffers from poor internal tuber quality and high scab susceptibility. On the contrary, cultivar ‘Superior’ is known to have excellent tuber internal quality and moderately scab resistance. In addition, this cultivar is known to have high tuber calcium as compared to ‘Atlantic’. The present study intended to generate populations that can be suitable for the genetic study of tuber calcium, internal quality, common scab, and other commercially important traits such as yield, specific gravity and chip quality at the tetraploid level. Two populations obtained by reciprocally crossing the cultivars ‘Atlantic’ and ‘Superior’ were evaluated during 2009 to 2012 at Hancock, Wisconsin. Significant genotype effects and moderately low to high broad-sense heritabilities were identified for all traits evaluated indicating that the observed phenotypic variation has an important genetic component. In addition, the parents differed significantly for all traits across trials, and most genotypes performed in between the two parents but some genotypes were more extreme than the parents. Furthermore, evidence of reciprocal effects was found for some traits. In addition to learning about the genetics of these important traits we were able to identify some genotypes that combined the commercially desired traits of the two cultivars.ResumenEs de gran interés para fitomejoradores y para la industria de la papa el desarrollar variedades de freído con calidad de tubérculo mejorada y resistencia a enfermedades. Una variedad de freído popular, “Atlantic”, es deseable por su alto rendimiento y gravedad. No obstante, esta variedad sufre de pobre calidad interna de tubérculo y de alta susceptibilidad a la roña. Por el contrario, la variedad “Superior” se sabe que tiene excelente calidad interna de tubérculo y resistencia moderada a la roña. Además, esta variedad se sabe que tiene alto contenido de calcio en el tubérculo al compararla con “Atlantic”. El presente estudio pretendió generar poblaciones que pueden ser deseables para el estudio genético de calcio en el tubérculo, calidad interna, resistencia a la roña común, y otras características económicamente importantes como el rendimiento, gravedad específica, y calidad de freído a nivel tetraploide. Durante el 2009 al 2012, se evaluaron dos poblaciones obtenidas mediante cruzas recíprocas con “Atlantic” y “Superior” en Hancock, Wisconsin. Se identificaron efectos significativos de genotipo y heredabilidades de moderadamente bajas a altas en un amplio sentido para todos los caracteres evaluados, indicando que la variación fenotípica observada tiene un componente genético importante. Además, los progenitores difirieron significativamente para todos los caracteres en todos los ensayos, y la mayoría de los genotipos se comportaron dentro de la amplitud de los dos progenitores, pero algunos genotipos estuvieron más allá de los extremos de los padres. Aún más, se encontró evidencia de efectos recíprocos para algunos caracteres. Además de aprender sobre la genética de estos caracteres importantes, fuimos capaces de identificar algunos genotipos que combinaron los caracteres deseados comerciales de las dos variedades.

Potential for improving freezing stress tolerance of wild potato germplasm by supplemental calcium fertilization

The main objective of the present study was to investigate the influence of supplemental calcium fertilization on the levels of freezing tolerance in different wild potato species. For this purpose, the freezing tolerance of a broad spectrum of theSolatium taxa was evaluated with and without supplemental calcium fertilization. Previous studies have shown that there is a large variation in the calcium accumulation capabilities among species and among various accessions within species. While this study confirms such variation, no direct relationship between the leaf calcium content and the improvement in freezing tolerance was found. Nevertheless, overall 45% of the species accessions had significant higher leaf calcium content and 52% of the species accessions showed a significant drop in the frost score average at the p<0.05 level. In terms of this experiment, a drop in the frost scores meant an improvement to withstand cold. One third of the frost tolerant accessions and 41% of the frost sensitive accessions showed both, a significant increase in leaf calcium content and at the same time a significant lower average frost score. The different response observed among the accessions may suggest that even though most of the accessions are able to accumulate calcium, only some of them may have the ability to benefit from the supplemental calcium. Future breeding schemes may be able to use this information for selecting clones that would respond positively to calcium fertilization in terms of frost survival. Results of this study also suggest that calcium fertilization may be used as a rather inexpensive cultural practice for protecting potatoes from frost damage. The results of the present study also suggest that soil calcium levels should be taken into consideration when freezing tolerance of potato germplasm is being evaluated.CompendioEl objetivo principal de este trabajo fue investigar si la fertilization con calcio puede incrementar los niveles de tolerancia a heladas en diferentes especies silvestres de papa. Para esto, la tolerancia a heladas fue evaluada en varias especies del género Solarium con y sin calcio como suplemento. Estudios anteriores han demostrado una gran variabilidad inter e intra-especifica (diferencia entre especies y accesiones de una especie) en la capacidad de acumular calcio. Además de confirmar dicha variabilidad, nuestros resultados también demostraron que no existe una relatión directe entre la concentratión de calcio en las hojas y la resistencia a heladas. Sin embargo, 45% de las accesiones aumentaron significativamente la concentratión de calcio en las hojas y 52% de las accesiones aumentaron significativamente su tolerancia a heladas (p<0.05). Un tercio de las accesiones tolerantes a heladas y 41% de las accesiones susceptibles a heladas exhibieron un aumento significativo en el contenido de calcio en las hojas y mayor tolerancia a heladas. Esta diferencia en la respuesta al daño por heladas sugiere que a pesar que la mayoria de accesiones son capaces de acumular calcio, sólo algunas tienen la habilidad de utilizar calcio para mejorar su tolerancia a bajas temperaturas. Futuros programas de mejoramiento pueden utilizar esta informatión para la selectión de clones que respondan positivamente a la fertilizatión con calcio en términos de sobrevivencia a bajas temperaturas. Adicionalmente, nuestros resultados sugieren que la fertilizatión con calcio puede ser un factor importante y económico en la protectión del cultivo de papa contra el daño causado por heladas. Los resultados de este trabajo también sugieren la consideratión de los niveles de calcio en el suelo durante la evaluatión del germoplasma de papa con resistancia a heladas.

Gibberellin-deficient dwarfs in potato vary in exogenous GA3 response when thega 1 allele is in different genetic backgrounds

Gibberellins (GAs) are involved in internode elongation and other important processes such as seed germination, flowering, maturation, tuberization, and tuber dormancy. The discovery of GA-deficient mutants enabled further study of the role of these hormones in many plant processes. GA-deficient mutants lack the ability to produce adequate amounts of gibberellin for normal growth, resulting in a rosette type growth and short internodes. Thega1 mutant allele was introduced into various genetic backgrounds including differentSolanum species and ploidies. Diploid GA-deficient genotypes were obtained by crossing haploidSolanum tuberosum ssp.andigena withSolanum chacoense. The progeny was then bulked and intermated to produce F2 individuals. Tetraploid GA-deficient genotypes were obtained by crossingS. tuberosum ssp.andigena withSolanum sucrense and withSolanum gourlayi. The two resulting progenies were then bulked and intermated. Diploid and tetraploid GA-deficient genotypes were grown on MS media containing different levels of gibberellin (GA3). Plant height and visual observations were made as a way to assess the response of these genotypes to GA3. Concentration of 0.1 µM GA3 and lower failed to restore normal plant height in both diploid and tetraploid genotypes. Normal plant height was restored in most of the GA-deficient genotypes when concentrations between 0.8 and 1.2 µM GA3 were used. We found some important differences between these genotypes: (1) the level of GA3 to restore normal plant height varies among the GA-deficient genotypes, some needed more GA3 than others to grow normally; (2) the time to respond to the presence of GA3 in the media differs between the GA-deficient genotypes, (3) tetraploid genotypes exhibited normal growth and internode length in response to GA3, while diploid genotypes tended to show a rosette-type growth at the apical end. These results suggest thatga1 mutants can be affected by a series of modifier genes and/or iso-alleles. The importance of variable response to GA among dwarf individuals is two fold: (1) experiments measuring GA response should choose and clonally multiply one genotype to ensure uniform optimal response to GA application; and (2) variation betweenga1 mutant phenotypes could be used to characterize GA-response modifier genes.ResumenLas giberelinas (GAs) están involucradas en el crecimiento internodal y en otros procesos importantes como germinación de semillas, florecimiento, maduración, tuberización y dormancia del tubérculo. El descubrimiento de mutantes deficientes en GA ha permitido estudiar el rol de estas hormonas en muchos procesos en la planta. Los mutantes deficientes en GA carecen de la habilidad de producir cantidades adecuadas de giberelina para tener un crecimiento normal, resultando en un crecimiento tipo roseta y espacio internodal corto. El alelo mutantega1 fue introducido en varios materiales genéticos, incluyendo diferentes especies deSolanum y diferentes ploidías. Genotipos diploides deficientes en GA fueron obtenidos cruzando haploides deS. tuberosum ssp.andigena conS. chacoense. La progenie fue después combinada y entrecruzada para producer individuos F2. Genotipos tetraploides deficientes en GA fueron obtenidos cruzandoS. tuberosum ssp.andigena conS. sucrense y conS. gourlayi. Las dos progenies resultantes fueron combinadas y entrecruzadas. Los genotipos diploides y tetraploides deficientes en GA fueron cultivadosin vitro en medio de cultivo MS conteniendo diferentes niveles de giberelina (GA3). La altura de la planta y observaciones visuales fueron utilizadas como parámetros para evaluar la respuesta de los genotipos a GA3. Concentraciones de 0.1 µM GA3 y menores no restauraron la altura normal de la planta en los dos tipos de genotipos, diploide y tetraploide. La altura normal de la planta fue restaurada en la mayoría de los genotipos deficientes en GA cuando las concentraciones utilizadas fueron entre 0.8 y 1.2 µM GA3. Este estudio encontró diferencias importantes entre estos genotipos: (1) el nivel de GA3 necesario para restaurar la altura normal de la planta varía entre los diferentes genotipos deficientes en GA, algunos necesitan más GA3 que otros para crecer normalmente; (2) el tiempo en el cual la planta responde a la presencia de GA3 en el medio es diferente entre los genotipos deficientes de GA; (3) los genotipos tetraploides exhibieron crecimiento y espacio inter-nodal normal en respuesta al GA3 presente en el medio de cultivo, mientras que los diploides tendieron a mostrar un crecimiento tipo roseta en el extremo apical de la planta. Estos resultados sugieren que los mutantesga1 pueden estar afectados por una serie de modificadores genéticos y/o iso-alelos. La importancia de la presencia de modificadores y/o isoalelos son dos: (1) experimentos que miden la respuesta a GA deben elegir y multiplicar clonalmente un solo genotipo para asegurar una respuesta óptima y uniforme a la aplicación de GA; y (2) la variación fenotípica entre los mutantesga1 puede ser utilizada para caracterizar los modificadores genéticos que pueden estar involucrados en la respuesta a GA.

Understanding Genetic Control of Freezing Resistance Using Potato Species as a Model System

Freezing stress resistance is generally regarded as a complex trait with multigenic inheritance (Marshall, 1982; Stushnoff et al., 1984; Blum, 1988). However, there is no consensus on the mode of gene action. For example the gene action for freezing tolerance has been reported to vary from recessive (Puchkov and Zhirov, 1978) to partially dominant (Parodi et al., 1983; Gullord et al., 1975) to both additive and non-additive (Sutka, 1994) in winter wheat, largely additive (Daday and Greenham, 1960) to dominant (Perry et al., 1987) in Alfalfa. The lack of consensus is, in part, due to heavy reliance on field test for assessing winter survival. Each winter is different in terms of the early fall frost episodes, lowest temperature, snow cover, mid-winter thaw periods followed by cold temperatures. Thus field selection has many inherent problems. Ideally one hopes for a “test frost episode” or a “test winter” that is severe enough to kill the most sensitive genotypes, cause various degrees of injury to intermediate genotypes, and cause no injury to most resistant genotypes. However such test frost episodes or test winters are rare. Thus when evaluating under field conditions one may not get the same results every winter or every frost episode. For example it has been shown that severity of winter or the stress level can determine whether the control of freezing tolerance was recessive or dominant (Muehlbauer et al., 1970). Furthermore, rank order of wheat cultivars for hardiness has been found to depend on the hardening technique used (Roberts, 1986).

Solanum commersonii cytoplasm does not improve freezing tolerance in substitution backcross hybrids with frost-sensitive potato species

Solanum commersonii Dun. (cmm) is the most frost hardy wild potato species known, being able to tolerate an acute freezing episode to about -5 C and further acclimate to tolerate −10 C after being exposed to chilling temperatures for several days. Breeding with this species to incorporate its frost-hardiness traits can be accomplished by standard sexual hybridization or protoplast fusion. These methods can result in hybrids that vary in contribution of the cmm plastome. To test the effect of cmm cytoplasm, cytoplasmic substitution backcross hybrids were made with three very frost-sensitive species,S. brachistotrichum, S. cardiophyllum, andS. pinnatisectum, by usingS. commersonii as the female to make an F1, then performing repeated backcross (BC) using the sensitive species as males. Relative freezing tolerance (RFT) of all genotypes was assessed by measurement of ion leakage of excised terminal leaflets subjected to a controlled ice nucleation and simulated freeze-thaw stress. Even against the background of these very sensitive species’ genomes, the cmm cytoplasm of substitution hybrids promoted insignificant improvement in frost hardiness or ability to acclimate. We conclude that either (1) cmm cytoplasm does not contribute to frost hardiness, or (2) if cmm cytoplasmic frost hardiness genes do exist, they must be epistatic to (depend on the presence of) nuclear hardiness genes for expression.

Marker-assisted genetic analysis of non-acclimated freezing tolerance and cold acclimation capacity in a backcrossSolarium population

Random amplified polymorphic DNA (RAPD) and simple sequence repeat (SSR) markers were used to construct a partial genetic linkage map in a potato backcross population. The population, derived from two diploid wildSolatium species (frost tolerant, able to cold acclimateS. commersonii; frost sensitive, unable to cold acclimateS. cardiophyllum), was used to map quantitative trait loci (QTL) of non-acclimated relative freezing tolerance (NARFT) and cold acclimation capacity (CAC). Precise assessment of these traits allowed distinction of small but significant differences among 35 backcross genotypes. NARFT and CAC were not correlated in the segregating population, suggesting independent genetic control for these two major components of freezing tolerance. The linkage map spanned 479.4 cM and included 77 RAPD markers and two SSR markers, with 38 RAPD and 10 SSR unassigned markers. Two QTLs for NARFT were detected in two different linkage groups, accounting for 44.0% of the phenotypic variation for this trait. Two QTLs for CAC were detected, accounting for 24.9% of the phenotypic variation for this trait. QTLs for NARFT and CAC were detected at separate genomic regions, in support of the independent genetic control of these two traits. QTLs for NARFT and CAC were detected in a linkage group identified as part of chromosome V, suggesting that such chromosome constitutes a prime candidate for fine-mapping. Due to the relatively small progeny size evaluated in this study, additional QTLs for NARFT and CAC could have been involved but not identified. Therefore, the conclusions derived from this study should be considered preliminary.ResumenMarcadores de DNA polimórfico amplificado al azar (RAPD) y de secuencias simples repetidas (SSR) fueron utilizadas para construir un mapa parcial de ligamiento genético en una población de retro-cruza de papa. Esta población fue derivada de dos especies silvestres diploides,S. commersonii (resistente a heladas, capaz de acclimatarse a bajas temperaturas) yS. cardiophyllum (sensible a heladas, incapaz de aclimatarse a bajas temperaturas), y se utilizó para mapear loci de carácteres cuantitativos (QTL) para la tolerancia relativa a heladas sin aclimatación a bajas temperaturas (NARFT) y la capacidad de aclimatarse a bajas temperaturas (CAC). La determinacién precisa de estos dos caracteres permitió encontrar diferencias pequeñas pero significativas entre los 35 genotipos de la retro-cruza. La correlación entre NARFT y CAC no fue significativa en la población segregante, sugieriendo que existe un control genético independiente para cada uno de estos dos componentes mayores de la tolerancia a heladas. El tamaño del mapa fue de 479.4cM e incluyó 77 marcadores RAPD y dos marcadores SSR; con 38 marcadores RAPD y 10 marcadores SSR sin asignar. Para NARFT, dos QTLs fueron detectados en dos diferentes grupos de ligamiento representando 44.0% de la variación fenotípica observada en este carácter. Para CAC, dos QTLs fueron detectados, los cuales representaron 24.9% de la variación fenotípica observada en este carácter. Los QTLs para NARFT y CAC fueron detectados en diferentes regiones genomicas, confirmando el control genético independiente de estos dos caracteres. Los QTLs para NARFT y CAC fueron detectados en un grupo de ligamiento identificado como parte del cromosoma V, sugiriendo que dicho cromosoma podria ser un candidato principal para mapeo fino. Debido a que el tamano de la población evaluada en este estudio fue relativamente pequeño, QTLs adicionales para NARFT y CAC podrían existir. En consecuencia, las conclusiones derivadas de este estudio deben ser consideradas como preliminares.

Genetic diversity of wild potato of the USA.

Genetic gains cannot be easily fixed in potato due to obligatory outbreeding. The wild diploid species have biodiversity for economic traits that the potato breeders can use to produce new varieties. Using the dominant self-incompatibility inhib-itor Sli gene from M6 we are modifying self-incompatible diploid species hybrids to a self-compatible population that will be used to create diploid inbred lines. We are developing a recurrent selection population for photoperiod adaptability, self-compatibility and cultivated tuber traits. The germplasm is composed of a mixture of five species (Solanum berthaultii, S. chacoence, S. microdontum, S. tuberosum Grp. Phureja and S. tarijense). The foundation lines and recurrent selection cycles have been SNP genotyped to fingerprint the germplasm and evaluate the recurrent selection process. Secondly, we have phenotyped an S2 population for self-compatibility for mapping purposes and also to continue to develop a recombi-nant inbred line (RIL) population for future trait mapping studies and to characterize inbreeding effects in the population as it progresses towards homozygosity. Micronutrient malnutrition is among the most widespread public health problems in the developing world. Lack of iron (Fe) and zinc (Zn) in the diet are among the leading causes of this malnutrition. Women of fertile age and children are most vulnerable to micronutrient malnutrition. More nutritious and safe food crops are vital to minimize malnutrition and promote healthier lives. As part of a food-based approach to help reduce micronutri-ent malnutrition, Potato biofortification breeding at international potato center (CIP) has resulted in new generations of biofortified potatoes with up to 35 mg/kg DW Fe and 36 mg/kg DW Zn from the baselines of 19 and 17 mg/kg DW of Fe and Zn, respectively. CIPs biofortification breeding has been carried out in a recurrent selection scheme using diploid Andean landrace potatoes having relatively high Fe and Zn and diverse shape, color and culinary attributes. The resulting population from this breeding process has been introduced to the East African highlands to assess their adaptation outside of the Andes. More than 1000 recurrent selection cycle III genotypes were propagated in Ethiopia from 16 true seed families from crosses involving parents from cycle-II biofortified populations developed at CIP Lima, Peru. These genotypes were introduced to Rwanda and are currently under field evaluation and selection both in Ethiopia and Rwanda. Preliminary results of field performance of these selections revealed that diploid potatoes adapt fairly well to East African highlands. Fe and Zn content of more …