D. E. Halseth

Postharvest application of organic and inorganic salts for suppression of silver scurf on potato tubers

Seven organic and inorganic salts were tested for suppression of silver scurf, a postharvest disease of potato tubers caused by Helminthosporium solani. Potassium sorbate, calcium propionate, sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, and ammonium bicarbonate were added to V8 agar at concentrations of 0.06-0.2 M. Radial growth of H. solani was significantly reduced (P < 0.05) by all salts at all concentrations. All salts except sodium bicarbonate and potassium bicarbonate were fungicidal at 0.2 M. Effects of postharvest salt treatments on disease severity and sporulation of H. solani on inoculated and naturally infected potato tubers were evaluated in separate experiments. Greenhouse-grown tubers were inoculated with H. solani spore suspensions (2 × 105 spores/ml), incubated for 5 days, dipped into 0.2 M solutions of each of the salts, and incubated in a moist chamber at 22-24°C for 6 weeks. All salt treatments prevented lesion development and sporulation of H. solani and differed significantly (P < 0.05) from the control. Postharvest applications of test compounds (0.2M) also significantly (P < 0.05) reduced disease severity and H. solani sporulation on naturally infected, field-grown tubers after 15 weeks of storage at 10°C. Salt treatments did not differ in disease or pathogen suppression. These relatively nontoxic organic and inorganic salts have potential as postharvest applications for control of silver scurf.

Eva:A midseason golden nematode- and virus-resistant variety for use as tablestock or chipstock

Eva is a new potato variety being released by the New York and Pennsylvania Experiment Stations. Eva is notable for its bright clear skin and attractive round to oval shape. It produces a chip color comparable to Monona from 9 C storage and has specific gravity 014 less than that of Atlantic. It has exceptionally long tuber dormancy and has extreme resistance to PVX, PVY, and race RO1 of the golden nematode. Scab resistance is like that of Monona. It is expected that Eva will find primary acceptance as a tablestock variety.ResumenEva es una nueva variedad de papa recientemente liberadad por la Estación Experimental de Pennsylvania y Nueva York. Eva se caracteriza por su piel clara y brillante y una atractiva forma semi ovalada. Produce hojuelas de un color similar a las de Monona, se almacena desde 9°C y su gravedad específica es 014 menos que Atlantic. Los tubérculos poseen una dormancia excepcionalmente larga y tiene resistencia extrema a PVX, PVY y la raza RO1 del nematodo dorado. La textura de su cáscara es similar a la Monona. Se espera que Eva sea aceptada como una variedad favorita para la mesa.

Pike: A full season scab and golden nematode resistant chipstock variety

Pike is a chipstock variety released jointly by the Cornell and Pennsylvania Experiment Stations in March 1996. Pike has a specific gravity comparable to Atlantic and the ability to produce light-colored chips after 7 C storage. Most of the chip color data were taken in December, January, and February. It has scab resistance comparable to that of Superior and is golden nematode resistant. It is a full season variety, somewhat earlier than Snowden. In 23 trials in New York, internal necrosis and hollow heart of Pike was 5% compared to 18% for Atlantic. When grown at high temperatures, Pike is susceptible to a unique expression o f heat necrosis that is net-like in appearance which is different from the internal brown spot of Atlantic. The yield has been about 95% of the yield of Atlantic.

Elba: A late maturing, blight resistant potato variety

Elba is a high yielding cultivar which combines resistance to the golden nematode, foliar infection byPhytophthora infestans andAlternaria solani, andVerticillium wilt. Elba is a late maturing tablestock cultivar especially well adapted to organic soils. In small plots and on farmers’ fields it has demonstrated its worth in reducing the need for foliar fungicides to prevent blight.ResumenElba, es una variedad de alto rendimiento que combina la resistencia al nematodo dorado de la papa, a las infecciones foliares porPhytophthora infestans yAlternaria solani, y a la marchitez porVerticillium. Elba es una variedad importante de maduración tardía especialmente adaptada a suelos orgánicos. En parcelas pequenas, y en campos de los agricultores, ha demostrado su valor en la reduccion de la necesidad de aplicar fungicidas foliares para prevenir el tizön.

Identification of Farmer Priorities in Potato Production Through Participatory Variety Selection

A substantial number of farmers in northwest Ethiopia grow potato in the dry season (“Belmehr”, March to August) when rainfall is not dependable for the growth of the crop, resulting in lower yield. Ethiopian Agricultural Research Institutes have tried to change the situation by releasing new late blight tolerant varieties that potentially could allow for production of the crop in the rainy season (“Meher”, May to October). Despite these efforts, the majority of the farmers still grow potato in the Belmehr season using older, local varieties. Cognizant of this fact, this study aimed to characterize the major potato production problems in the two seasons, to identify the traits that farmers consider most important when selecting potato varieties, and to assess the performance of widely grown local as well as newly developed varieties. The study was conducted at sites representing two major agroecological zones in northwest Ethiopia and during both production seasons using 12 varieties (9 local and 3 new) with a ‘participatory variety selection’ approach. During the Belmehr season, erratic rainfall resulted in low yield and lower average tuber weight. By contrast, in the Meher season, late blight, desiccating wind and severe precipitation, including hail, limited production. These factors were important in both agroecological zones, with varying degrees of importance. Twenty-three traits were found to influence the varieties that farmers selected, with the degree of importance of each trait differing between agroecological zones and gender groups. Some local varieties yielded as well as new varieties in both seasons. Overall, we found participatory variety selection to be an effective approach for identifying factors important for the adoption of potato varieties, including factors that may not be addressed in conventional potato breeding programs.ResumenUn número substancial de agricultores en el noroeste de Etiopía cultivan papa en la época seca (“Belmehr”, marzo a agosto) cuando no se depende de la lluvia para el crecimiento del cultivo, lo que resulta en rendimiento más bajo. Los Institutos de Investigación Agrícola de Etiopía han intentado cambiar la situación mediante la liberación de nuevas variedades tolerantes al tizón tardío que pudieran permitir potencialmente la producción del cultivo en la época de lluvias (“Meher”, mayo a octubre). A pesar de estos esfuerzos, la mayoría de los agricultores aún cultivan papa en la temporada Belmehr usando variedades más viejas, locales. En conocimiento de este hecho, este estudio tuvo como propósito la caracterización de los principales problemas en la producción de papa en las dos épocas, para identificar los rasgos que los productores consideren como los más importantes cuando estén seleccionando variedades de papa, y analizar el comportamiento de variedades locales ampliamente cultivadas, así como las recientemente desarrolladas. Se condujo el estudio en sitios que representaran dos zonas agroecológicas mayores en el noroeste de Etiopía y durante ambas temporadas de producción, usando 12 variedades (9 locales y 3 nuevas) con un enfoque de “selección participativa de variedades”. Durante el ciclo Belmehr, la lluvia errática dio como resultado bajo rendimiento y un promedio de peso de tubérculo más bajo. En contraste, en el ciclo Meher, el tizón tardío, el viento deshidratador y precipitación severa, incluyendo granizo, limitaron la producción. Estos factores fueron importantes en ambas zonas agroecológicas, con diversos niveles de importancia. Se encontraron 23 características que influenciaron las variedades que seleccionaron los productores, con el grado de importancia de cada característica difiriendo entre las zonas agroecológicas y grupos de género. Algunas variedades locales rindieron tan bien como las nuevas en ambos ciclos. En general, encontramos que la selección de variedades participativa fue un enfoque efectivo en la identificación de factores importantes para la adopción de variedades de papa, incluyendo aspectos que pudieran no estar considerados en programas convencionales de mejoramiento de papa.

Andover: An early to midseason golden nematode resistant variety for use as chipstock or tablestock

Andover may be used as an early to midseason tablestock and chipstock variety. It has a very rapid emergence and early tuber set. The vine maturity is similar to Superior in the absence of severe stress. In New York trials harvested 90 days after planting, the yields of Andover and Superior are nearly equal, 274 cwt/A. At 120 days, over eight seasons at two Ithaca locations, Andover yielded 87% Atlantic. Andover appears to be susceptible to drought and heat stress which can cause early senescence and reduce late season yields. It has few external and internal defectS. Specific gravity is high for an early variety, being .009 less than Atlantic. Andover has excellent chip color from the field from a range of environments and from 7 C storage. It has good boiling and baking properties. The mealiness of the baked potatoes is especially good. Tuber dormancy is two weeks longer than Atlantic. The reaction to common scab is like that of Monona, which is considered to be resistant. It is also resistant to powdery scab and the golden nematode.

Allegany: a late season golden nematode resistant variety.

Allegany is a golden nematode resistant variety with potential for both tablestock and chipping. It is late in vine maturity and when allowed to grow full season, has very high yield potential. In the Northeast, the specific gravity and chip color of tubers soon after harvest and after 10°C storage are comparable to Norchip. The tubers have exceptionally long dormancy Allegany is resistant to early blight, Verticillium wilt, and scab as well as the golden nematode.

Kanona: A golden nematode resistant potato variety for the chipping industry

Kanona is a golden nematode resistant variety with chipping characteristics similar to those of Monona. The color of chips from tubers stored at 7.2°C or 10°C and chipped the day after being removed from storage has been equal to or better than Monona in the majority of trials. The specific gravity is .005 higher than Monona. The maturity is similar to Monona’s, but the vigor of the vines is greater. The yield is similar to that of Monona.

Genetic Diversity and Relationship of Ethiopian Potato Varieties to Germplasm from North America, Europe and the International Potato Center

Potato is an increasingly important crop in Ethiopia, but the origin of local cultivars grown throughout the country is unknown. To evaluate the genetic diversity of Ethiopian potato cultivars, and to assess their relationship with germplasm from North America, Europe and the International Potato Center (CIP), 8303 SNP markers were used to characterize 44 local Ethiopian cultivars, as well as 26 CIP, 22 American and 17 European potato cultivars and advanced breeding clones. The marker data revealed that most of the local cultivars were duplicates; among the 44 cultivars tested, only 15 unique genotypes were observed. Principal component and neighbor-joining dendrogram analyses showed that American, European and CIP germplasm form three distinct clusters, with older Ethiopian cultivars overlapping the European cultivars, suggesting that the oldest local cultivars are of European descent. Local cultivars overall separated into two distinct clusters, suggesting that at least two distinct introductions gave rise to current local cultivars in Ethiopia. Ethiopian germplasm harbors comparable levels of genetic diversity to American, European, and CIP germplasm and could provide the foundation for a national potato breeding program.ResumenLa papa es un cultivo con importancia en aumento en Etiopía, pero se desconoce el origen de las variedades locales cultivadas a lo largo del País. Para evaluar la diversidad genética de las variedades de papa de Etiopía, y para analizar su relación con germoplasma de Norteamérica, Europa y el Centro Internacional de la Papa (CIP), se usaron 8303 marcadores SNP para caracterizar 44 variedades locales de Etiopía, así como 26 de CIP, 22 americanas y 17 europeas y clones avanzados de mejoramiento. Los datos de los marcadores revelaron que la mayoría de las variedades locales fueron duplicadas; entre las 44 variedades probadas, se observaron solamente 15 genotipos únicos. El componente principal y el dendrograma de unión de vecinos mostraron que el germoplasma americano, europeo y del CIP de tres diferentes grupos, con variedades viejas de Etiopía, se traslapaban con los europeos, sugiriendo que las variedades viejas locales son de descendencia europea. Las variedades locales en general se separaron en dos distintos grupos, lo que sugiere que por lo menos dos introducciones distintas hicieron que surgieran las variedades locales actuales en Etiopía. El germoplasma etíope conserva niveles comparables de diversidad genética respecto al americano, europeo y del CIP, y pudiera suministrar la base para un programa nacional de mejoramiento de papa.

Monticello: A mid-season variety with good tuber appearance and chipping potential from mid-to long-term storage

Monticello (NY102), a new medium-maturing, roundwhite chipping variety was released in 2003 by the University of Maine and Cornell University. It is primarily intended for use in the chipping industry, especially from mid-to long-term storage. Its ability to chip from relatively long-term storage, low storage weight loss, and relatively long tuber dormancy should be particularly valuable. Tubers have shown a good ability to recondition and regain good chip color after periods of stress in storage. Monticello’s specific gravity typically averages only a few points lower than Atlantic, a variety that is widely used for out-of-field chipping in the eastern U.S. Chip color of Monticello has been very good from short-, mid-, and long-term storage. It has been grown successfully in commercial-scale tests in Maine since 1999 with combined seed and chipping production of more than 37 and 60 ha during 2001 and 2002, respectively. Research and commercial-scale trials in Maine have generally produced favorable yield and quality results relative to other storage chippers like Snowden. The tubers are bright and attractive with relatively few external defects. Tuber size tends to be fairly small and is ideal for chipping. Sensory panel tests have also shown that Monticello is good for boiling and baking. Although ideally suited for chipping, the fresh market may serve as a secondary market for this variety because of its typically good external appearance and cooking quality scores. Monticello has moderate to good common scab resistance and is resistant to golden nematode. It is moderately susceptible to blackspot bruise, powdery scab, and typical foliar diseases of potato. Although tubers can develop hollow heart and internal heat necrosis, Monticello is typically much less susceptible than Atlantic.ResumenLa nueva variedad de papa para hojuelas Monticello (NY 102), de madurez media, redonda y blanca ha sido liberada en el 2003 por las Universidades de Maine y de Cornell para su uso en la industria de hojuelas, especialmente para almacenamiento del tubérculo medio o prolongado. La habilidad del tubérculo de servir para hojuelas después de un período prolongado de almacenaje, baja pérdida de peso y período de latencia relativamente largo son particularmente valiosos. Los tubérculos han mostrado buena capacidad de recuperación del color de hojuelas después de ser reacondicionados y después de períodos de estrés en el almacén. La gravedad específica promedio de Monticello está a sólo unos pocos puntos por debajo de Atlantic, variedad ampliamente utilizada para su proceso inmediato en hojuelas en el este de EUA. El color de hojuelas de Monticello fue muy bueno después de almacenaje en períodos cortos, medianos o largos. Se ha cultivado con éxito en pruebas a escala comercial en Maine desde 1999 con semilla combinada y producción de hojuelas en más de 37 y 60 hectáreas durante 2001 y 2002 respectivamente. Las pruebas de investigación y a escala comercial en Maine han dado como resultado rendimientos y calidad favorable en relacion con otras variedades usadas en la producción de hojuelas como la variedad Snowden. Los tubérculos son brillantes y atractivos con relativamente pocos defectos externos. El tamaño del tubérculo tiende a ser relativamente pequeño y es ideal para hojuelas. Las pruebas de panel sensorial han demostrado también que Monticello es bueno para cocción y horneado. Aunque idealmente satisfactorio para hojuelas, el mercado para el producto fresco puede ser como una option secundaria para esta variedad por su buena apariencia externa y calidad de cocción. Monticello tiene una moderada a buena resistencia a la sarna común y es resistente al nematodo dorado. Es moderadamente resistente a la mancha negra, rona y enfermedades foliares tipicas de la papa. Aunque los tubérculos pueden desarrollar corazén vacío y necrosis interna, Monticello es típicamente menos susceptible que Atlantic.