Mark J. Pavek

Strain-Specific Resistance to Potato virus Y (PVY) in Potato and Its Effect on the Relative Abundance of PVY Strains in Commercial Potato Fields

Potato virus Y (PVY) is a serious threat to potato production due to effects on tuber yield and quality, in particular, due to induction of potato tuber necrotic ringspot disease (PTNRD), typically associated with recombinant strains of PVY. These recombinant strains have been spreading in the United States for the past several years, although the reasons for this continuing spread remained unclear. To document and assess this spread between 2011 and 2015, strain composition of PVY isolates circulating in the Columbia Basin potato production area was determined from hundreds of seed lots of various cultivars. The proportion of nonrecombinant PVYO isolates circulating in Columbia Basin potato dropped ninefold during this period, from 63% of all PVY-positive plants in 2011 to less than 7% in 2015. This drop in PVYO was concomitant with the rise of the recombinant PVYN-Wi strain incidence, from less than 27% of all PVY-positive plants in 2011 to 53% in 2015. The proportion of the PVYNTN recombinant strain, associated with PTNRD symptoms in susceptible cultivars, increased from 7% in 2011 to approximately 24% in 2015. To further address the shift in strain abundance, screenhouse experiments were conducted and revealed that three of the four most popular potato cultivars grown in the Columbia Basin exhibited strain-specific resistance against PVYO. Reduced levels of systemic movement of PVYO in such cultivars would favor spread of recombinant strains in the field. The negative selection against the nonrecombinant PVYO strain is likely caused by the presence of the Nytbr gene identified in potato cultivars in laboratory experiments. Presence of strain-specific resistance genes in potato cultivars may represent the driving force changing PVY strain composition to predominantly recombinant strains in potato production areas.

A survey of stand establishment and in-row spacing uniformity in Washington potato fields

Missing plants and non-uniform in-row plant spacing can result in economic loss for potato growers. In-row seedpiece and plant spacing uniformity of 70 Washington potato fields was measured, and factors contributing to missing plants investigated from 2000 through 2002. Ninety-one percent of the fields were planted with cut seedpieces, and the remaining 9% were planted with cut seedpieces, and the remaining 9% were planted with whole, uncut seed tubers. Russet-type cultivars were planted in 79% of the fields, and the remaining 21% were planted with red-skinned and yellow- and white-fleshed cultivars. Seedpiece or plant spacing deviated an average of 25% from the intended spacing mean, with a range of 7% to 43%. Coefficients of variation (CV) for grower in-row plant and seedpiece spacing ranged from 18% to 69% compared with a hand-planted check average of 13%. Based on the growers’ intentions, the average plant population of the 70 fields should have been 44,000 plants ha−1, but averaged only 40,600 plants ha−1. On average, 6% of the grower-intended stand was missing because of planter skips, while less than 1% was missing due to seedpiece failure or decay. There were 1,980 clumped seedpieces ha−1 and each clump typically contained two seedpieces. Twenty-one percent of the fields had at least 700 planter-skips ha−1 where three or more consecutive plants were missing. Despite management efforts, planters were typically unable to place seed uniformly at the intended spacing. Improved planter and seed-cutting-operation management along with new planter technology would likely improve Washington potato stands.ResumenEspacios vacíos y falta de unifomidad en el espaciamiento de plantas en el surco puede resultar en pérdidas económicas para los productores. La uniformidad en el espaciamiento de la semilla fue estudiada en 70 campos de papa de Washington y los factores que contribuyen a la presencia de espacios vacíos fueron investigados desde el 2000 al 2002. El 91% de los campos se sembró con semilla cortada y para el restante 9% se usó semilla entera. Los cultivares del tipo rojizo se sembraron en el 79% de los campos y el restante 21% se sembró con cultivares de piel roja y amarilla y pulpa blanca. El espaciamiento de semilla cortada o de plantas tuvo en promedio una desviación de 25% del promedio proyectado de espaciamiento, con un rango de 7 a 43%. Para plantas en surcos, los coeficientes de variancia (CV) de espaciamiento de la semilla estuvo entre 18 y 69% en comparación con el testigo sembrado manualmente, cuyo promedio estuvo en 13%. Basado en lo proyectado por el productor, el promedio de población de los 70 campos debería haber sido 44,000 plantas/ha−1, pero solo promedió 40,600 plantas/ha−1. Faltó el 6% de plantas proyectadas por el productor debido a escapes en la siembra, mientras que menos del 1% faltó debido a fallas de la semilla cortada o por pudrición. Hubo 1,980 pedazos agrupados de semilla cortada/ha−1 y cada grupo contenía típicamente dos pedazos de semilla. El 21% de los campos tuvo al menos 700 fallas/ha−1 debidas a la sembradora, donde faltaban tres o más plantas consecutivas. A pesar de los esfuerzos en el manejo, las sembradoras fueron incapaces de colocar la semilla uniformemente a la distancia conveniente. Sembradoras mejoradas y manejo de la operación de corte junto con una nueva tecnología de siembra parece que mejorarían los sembríos de papa en Washington.

AmaRosa, a Red Skinned, Red Fleshed Fingerling with High Phytonutrient Value

The diversity of traits in varieties of potato outside of its South American birthplace is a small subset of that available in the Andean center of origin. Among the traits that evoke most interest are skin and flesh pigments. Recent studies have pointed to the high antioxidant activity and potential healthful benefits from these pigments or other antioxidant compounds. The market for potatoes with unusual color patterns has been supplied largely by heirloom varieties of uncertain origin and the highly successful Yukon Gold. Interest has intensified and been transformed into a focused effort in the breeding of specialty varieties, remarkable for their unusual colors. The purpose of this paper is to describe a new potato variety in the Fingerling Class with red skin and red flesh.ResumenLa diversidad de caracteres en variedades de papa fuera de su lugar de origen en Sudamérica, es un pequeño subgrupo del que esta disponible en su centro de origen andino. Entre los caracteres que atraen más interés son los pigmentos de la piel y de la pulpa. Estudios recientes han enfatizado a la alta actividad antioxidante y a los potenciales beneficios para la salud de estos pigmentos u otros compuestos antioxidantes. El mercado de papas con patrones de color inusuales se ha surtido grandemente por variedades antiguas de origen incierto y por la altamente exitosa Yukon Gold. Se ha intensificado el interés y se ha transformado a un esfuerzo enfocado en el mejoramiento de variedades de especialidad, que sobresalen por sus colores poco comunes. El propósito de este artículo es describir una nueva variedad de papa en la clase de variedaes tipo dedo con piel y pulpa rojas.

Genetic Fingerprinting of Potato Varieties from the Northwest Potato Variety Development Program

The Northwest Potato Variety Development (NWPVD) Program has released 45 improved potato varieties since 1985. Thirty-four potato varieties, four breeding clones and two advanced selections from NWPVD Program, and six commonly-grown potato varieties were fingerprinted using 32 simple sequence repeat (SSR) markers and 12,808 single nucleotide polymorphism (SNP) markers. Of 32 SSR markers, 29 exhibited significant polymorphism across all the 46 potato clones studied. A total of 143 alleles were observed with an average of 4.6 alleles per SSR marker. These markers span all 12 chromosomes of potato, with a maximum of five markers from chromosome VIII and minimum of one marker from chromosome VI. The polymorphic information content (PIC) and expected heterozygosity (He) of the SSR markers ranges between 0.18 to 0.75 and 0.20 to 0.78, respectively. Based on PIC, He, and ease of scoring, we recommend a set of eight SSR markers: STG0016, STI0004, STI0012, STI0023, STI0030, STI0033, STM1016 and STM1104 for fingerprinting NWPVD varieties. Out of 12,808 SNPs, 88.8% resulted in reliable three cluster diploid calling of which 87.8% were polymorphic. Tetraploid calling resulted in 44.2% of SNPs of which 94.5% were polymorphic. Our study provided fingerprinting resources for the NWPVD varieties and can be used in issues related to intellectual property rights, ownership, trademark and diversity analysis.ResumenEl Programa de Desarrollo de Variedades de Papa Noroccidental (NWPVD, por sus siglas en inglés), ha liberado 45 variedades mejoradas de papa desde 1985. Se le obtuvo la huella digital molecular a 34 variedades de papa, cuatro clones para mejoramiento, y a dos selecciones avanzadas del Programa NWPVD, así como a seis variedades de papa de cultivo común, utilizando 32 marcadores de repeticiones de secuencias simples (SSR en inglés) y 12,808 marcadores de polimorfismo de nucleótidos simples (SNP). De los 32 marcadores SSR, 29 exhibieron polimorfismo significativo en todos los 46 clones de papa estudiados. Se observó un total de 143 alelos, con un promedio de 4.6 alelos por marcador SSR. Estos marcadores abarcaron los 12 cromosomas de la papa, con un máximo de cinco marcadores del cromosoma VIII y un mínimo de un marcador del cromosoma VI. El contenido de información polimórfica (PIC) y la heterocigocidad esperada (He) de los marcadores SSR fluctúa entre 0.18 a 0.75 y 0.20 a 0.78 respectivamente. Con base en el PIC, He, y las calificaciones, recomendamos un juego de ocho marcadores SSR: STG0016, STI0004, STI0012, STI0023, STI0030, STI0033, STM1016 y STM1104 para obtener la huella molecular digital de las variedades del NWPVD. De 12,808 SNPs, el 88.8% resultó en tres agrupamientos confiables de diploides identificados, de los cuales 87.8% fueron polimórficos. La identificación de tetraploides resultó en 44.2% de SNPs, de los cuales 94.5% fueron polimórficos. Nuestro estudio proporciona recursos de huellas moleculares para las variedades de NWPVD, y puede usarse en temas relacionados con derechos de propiedad intelectual, pertenencia, marcas registradas y análisis de diversidad.

Potato Tuber Length-Width Ratio Assessment Using Image Analysis

Potato tuber length to width (L/W) ratio is a critical crop trait evaluated during the development and selection of new cultivars to assess the effects of environment and management on tuber size and shape. The major challenges in manual measurement of L/W ratio are that it is labor-intensive, time consuming, and sometimes inconsistent. A high-throughput, digital image-based method for estimation of L/W ratio was developed in this study. Tests were conducted using tubers from a local retail market (red, white and russet) and from a field experiment with Payette Russet cultivar specifically designed to alter tuber size and shape. An image processing algorithm was developed to process the potato tuber images and the L/W ratio data from the images were compared to manual caliper measurements. A high accuracy in tuber L/W ratio estimation was consistently observed using image-based analysis. Among the different potato cultivars, red cultivars had a lower average accuracy in L/W ratio estimation of 94%, while other cultivars exhibited 96% and higher average accuracies.ResumenLa relación largo-ancho del tubérculo de la papa (L/W, por sus siglas en inglés), es un carácter crítico del cultivo que se evalúa durante el desarrollo y selección de nuevas variedades para analizar los efectos del ambiente y de manejo en el tamaño y forma del tubérculo. Los mayores retos en las mediciones manuales de la relación L/W son la mano de obra intensiva que se requiere, el tiempo que les lleva, y algunas veces las inconsistencias. En este estudio, se desarrolló un método integral, basado en imagen digital para la estimación de la relación L/W. Se condujeron pruebas usando tubérculos de un mercado de menudeo local (roja, blanca y tipo russet) y de un experimento de campo con la variedad Payette Russet diseñado específicamente para alterar el tamaño y la forma del tubérculo. Se desarrolló un algoritmo de procesamiento de imagen del tubérculo de papa, y los datos de la relación L/W de las imágenes se compararon con mediciones manuales de un calibrador (tipo vernier, nota del traductor). Mediante el uso de análisis basado en imágenes, se observó consistentemente una alta precisión en la estimación de la relación L/W del tubérculo. Entre las diferentes variedades de papa, las rojas tuvieron un promedio más bajo de precisión en la estimación de la relación L/W de 94%, mientras que otras variedades exhibieron promedio de precisiones de 96% y mayores.

Aerial multispectral imaging for crop hail damage assessment in potato

Aerial multispectral imaging is capable to assess crop hail damage in potato crops.Vegetation indices have potential to predict crop yield losses.Imaging within 10days after hail damage assists in quantifying damage levels.Hail damage during different growth stages can affect the recovery of potato crops. Crop loss assessment after an event of hailstorm can be inaccurate, subjective, and time consuming with the conventional method. Low-altitude, high-resolution aerial imaging using an unmanned aerial vehicle can be utilized for rapid assessment of target crops in a large scale, which can potentially improve the evaluation procedure. The goal of this study was to evaluate the feasibility of rapid and accurate assessment of crop damage due to simulated hailstorms using aerial multispectral imaging. Field experiments were conducted during two seasons in two potato varieties (Russet Norkotah, Ranger Russet) with three levels of mechanical defoliation (33%, 66%, and 99%) at three growth stages (tuber initiation, early bulk, and late bulk). All defoliation treatments were compared to the non-treated control plots (0% defoliation). Aerial multispectral images were collected between 77 and 108days after planting (0-60days after damage). Vegetation indices such as green normalized difference vegetation index (GNDVI), normalized difference vegetation index, and soil-adjusted vegetation index were calculated from replicate plots of different treatments. Results from two seasons showed similar trends in GNDVI values, with maximum effect of hail damage observed in early bulk stages. The mean GNDVI value was significantly lower in crops with the severe damage (99% defoliation) than others upon hail damage at the early bulk stage, with imaging after 10days after damage. The difference in GNDVI for crops with 33-66% damage could be detected within 10days after damage, and crop regrowth after that time period removed the effects of defoliation. The 99% defoliation damage at the early bulk stage also affected the crop yield significantly. Correlation analysis between vegetation indices and yield data indicated a strong relationship (r=0.77-0.90) for damage at the early bulk stage than other stages.

The potato: botany, production and uses.

1. History & Origin of Cultivated Potato Species 2. Potato Uses and Markets 3. Taxonomy 4. Tuber Development 5. Plant Growth and Development 6. Commercial Production and Cultural Management 7. Potato Water Use and Irrigation 8. Seed Production 9. Insect Pests 10. Nematodes 11. Weed Management 12. Fungal and Bacterial Pathogens 13. Potato Viruses 14. Physiological Disorders 15. Post Harvest Storage and Physiology 16. Traditional Breeding and Variety Development 17. Molecular Breeding 18. Biotechnology 19. Nutritional Value 20. Flavor

Huckleberry Gold: A Specialty Market Potato Cultivar with Purple-Skin, Yellow-Flesh, High Tuber Antioxidants, and Resistance to Potato Cyst Nematode (H1) and Potato virus X (Nb and Rx1)

Huckleberry Gold is a purple-skin, yellow-flesh fresh market cultivar with similar culinary qualities to the market standard Yukon Gold. It has lower specific gravity, sucrose and vitamin C content, but a significantly higher level of tuber antioxidants than Yukon Gold. Notable disease resistant characteristics are Potato virus X resistance based on the presence of molecular markers for the PVX resistance genes, Nb and Rx1. In addition it also has the H1 gene present which confers resistance to the potato cyst nematode, Globodera rostochiensis, which has been confirmed by bioassay to pathotype Ro1. The size profile of Huckleberry Gold is smaller than Yukon Gold, allowing a better fit into specialty markets that are geared to smaller size for fresh use. Huckleberry Gold represents the first purple-skin, yellow-flesh cultivar to come from the Northwest (Tri-State) Potato Variety Development program.ResumenHuckleberry Gold es una variedad de piel morada, pulpa amarilla para mercado fresco, con cualidades culinarias similares a las comunes de mercado de Yukon Gold. Tiene un contenido más bajo de gravedad específica, sacarosa y vitamina C, pero un nivel significativamente más alto de antioxidantes de tubérculo que Yukon Gold. Características notables de resistencia a enfermedades son la resistencia al virus X de la papa, con base en la presencia de marcadores moleculares para los genes de resistencia al PVX, Nb y Rx1. Además, también tiene el gen H1, que le confiere resistencia al nematodo de quiste de la papa, Globodera rostochiensis, que ha sido confirmado con un bioensayo al patotipo Ro1. El perfil del tamaño de Huckleberry Gold es más pequeño que el de Yukon Gold, permitiendo un mejor ajuste en los mercados de especialidad que están diseñados a tamaños más chicos para uso en fresco. Huckleberry Gold representa la primera variedad de piel morada, pulpa amarilla, proveniente del Programa Triestatal de Desarrollo de Variedades de Papa de la Región del Pacífico Noroccidental.

Classic Russet: A Potato Cultivar with Excellent Fresh Market Characteristics and High Yields of U.S. No. 1 Tubers Suitable for Early Harvest or Full-Season Production

Classic Russet is a medium maturing potato cultivar with rapid tuber bulking making it suitable for early harvest, as well as full-season production. Classic Russet is notable for its attractive tubers with medium russet skin and excellent culinary characteristics. It resulted from a 1995 cross between Blazer Russet and Summit Russet and was released in 2009 by the USDA-ARS and the Agricultural Experiment Stations of Idaho, Oregon and Washington and is a product of the Northwest Potato Variety (Tri-State) Development Program. Classic Russet also shows potential as an early season processing cultivar, with fry color comparable to Russet Burbank and Ranger Russet. Classic Russet total yields were comparable to Russet Norkotah and Ranger Russet in early harvest trials and comparable to Ranger Russet and Russet Burbank in full season trials. When averaged across sites in early harvest or full season trials, U.S. No. 1 yields of Classic Russet were generally greater than those of Russet Norkotah, Ranger Russet, and Russet Burbank. Protein content for Classic Russet is relatively high, averaging 22% higher than Ranger Russet, 32% higher than Russet Burbank and 24% higher than Russet Norkotah. Specific gravity of Classic Russet in early harvest trials was comparable to Russet Norkotah but lower than Ranger Russet and was similar to Russet Burbank in full season trials. The incidence of hollow heart in Classic Russet is low, similar to that of Ranger Russet. It is less susceptible to blackspot bruise than Russet Burbank, Ranger Russet and Russet Norkotah but shatter bruise can be a concern if not matured properly prior to harvest. Classic Russet is moderately resistant to common scab and dry rot and is moderately susceptible to foliar and tuber infections of early blight and symptoms of corky ringspot. It is susceptible to Verticillium wilt, soft rot, foliar and tuber late blight, PLRV and PLRV net necrosis, and the common strain of potato virus Y (PVY°).ResumenClassic Russet es una variedad de papa de madurez media con llenado rápido de tubérculo, haciéndola deseable para cosecha temprana, así como para producción de ciclo completo. Classic Russet es notable por sus tubérculos atractivos con piel corchosa intermedia y de características culinarias excelentes. Fue el resultado de una cruza de 1995 entre Blazer Russet y Summit Russet y se liberó en el 2009 por el USDA-ARS y las estaciones agrícolas experimentales de Idaho, Oregon y Washington y es un producto del Programa de Desarrollo de Variedades de Papa del Noroeste (Tri-State). Classic Russet también presenta potencial de una variedad temprana para proceso, con el color del freído comparable a Russet Burbank y Ranger Russet. Los rendimientos totales de Classic Russet fueron comparables a los de Russet Norkotah y Ranger Russet en ensayos de cosecha temprana y comparable a Ranger Russet y Russet Burbank en ensayos de ciclo completo. Cuando se promedió transversalmente en los sitios de los ensayos de ciclos corto y completo, los rendimientos de U.S. No. 1 de Classic Russet fueron generalmente mayores que los de Russet Norkotah, Ranger Russet, y Russet Burbank. El contenido protéico de Classic Russet es relativamente alto, promediando 22% mayor que Ranger Russet, 32% más alto que Russet Burbank y 24% más que Russet Norkotah. La gravedad específica de Classic Russet en los ensayos de cosecha temprana fue comparable a la de Russet Norkotah pero más baja que Ranger Russet y similar a la de Russet Burbank en ensayos de temporada completa. La incidencia de corazón hueco en Classic Russet es baja, similar a la de Ranger Russet. Es menos susceptible al oscurecimiento por daño mecánico que Russet Burbank, Ranger Russet y Russet Norkotah, pero la desintegración por golpes puede ser de cuidado si no se ha madurado apropiadamente antes de la cosecha. Classic Russet es moderadamente resistente a la roña común y a la pudrición seca y es moderadamente susceptible a las infecciones foliares y de tubérculo de tizón temprano y a los síntomas de la mancha anular corchosa. Es susceptible al marchitamiento por Verticillium, a la pudrición blanda, al tizón tardío en el follaje y en el tubérculo, PLRV y a la necrosis neta por PLRV, y a la variante común de virus Y (PVY°).

Agronomic and economic impact of missing and irregularly spaced potato plants

Missing and irregularly spaced potato plants compromise grower revenue. A recent survey of 70 commercial fields in Washington State, USA, indicated that in-row seedpiece and plant spacing was irregular due to multiple planter skips and clumped seedpieces. Seven percent (2950 missing plants ha−1) of the intended stand was missing: 6% from planter skips and 1% from nonviable seedpieces. To estimate economic loss to Washington potato growers, two potato (Solanum tuberosum) cultivars, Russet Burbank and Russet Norkotah, were grown in small-plot experiments designed to mimic spacing errors commonly found in Washington fields. Yield and economic values of uniform (optimum) spacing were compared to values coming from treatments that simulated planter skips/missing plants and seed clumps (doubles) in 2001 and 2002. The planter-skip treatments produced the lowest total, market, and U.S. No. 1 yields for both cultivars. In-row plants on both sides of a skip collectively compensated for 56% to 67% of the missing plant’s economic value. Plants in adjacent rows failed to compensate for their missing neighbor. Doubles reduced average tuber size for both cultivars compared with optimum spacing. Using processing market values, 2950 missing Russet Burbank plants ha−1 reduced seed-cost-adjusted gross income 2.9% or