R. Voss

Growth and yield response of two potato cultivars to various levels of applied water

SummaryThe effects of six levels of irrigation water supply on the growth and yield of two potato cultivars, Kennebec and White Rose, were examined in a field experiment conducted on a deep Yolo loam soil. Seasonal patterns of soil water depletion, water-use efficiency, leaf area development, and dry matter partitioning were evaluated.Total seasonal evapotranspiration (ET) ranged from 316 to 610 mm for the Kennebec cultivar and from 331 to 630 mm for White Rose. The contribution of soil water depletion to ET increased as the water supply decreased. The cultivars exhibited root activity to 150 cm below the soil surface under all treatments.The amount of applied water affected dry matter accumulation significantly. Both cultivars exhibited a high correlation between leaf area duration and final plant dry weight, suggesting that the effect of water stress on dry matter production was largely a function of effects on leaf area expansion and leaf senescence. Significant differences were not detected in partitioning of assimilates to the harvestable organs (harvest index) or on water-use efficiency during the season among different irrigation treatments and cultivars.In general, yield increased with increasing ET, but there was a slight yield depression in the wettest treatment, possibly due to poor soil aeration and nitrogen deficiency near the end of the season. White Rose had more defects in tuber shape and lower marketable yields under dry soil conditions than Kennebec. The final fresh-weight yield of marketable tubers ranged from 4.7 to 33.9 t/ha for White Rose and from 14.3 to 35.8 t/ha for Kennebec.

Lemhi Russet: A new high yielding potato variety with wide adaptation, attractive tubers, and high internal quality

Lemhi Russet, a new oblong, russet-skinned potato variety, was released by the U.S. Department of Agriculture and the Agricultural Experiment Stations of Idaho, Oregon, California, Washington, and North Dakota on September 23, 1980. The tubers of Lemhi Russet have been blockier, larger, 6% higher in solids, 50% lower in reducing sugars, and 25% higher in vitamin C than those of Russet Burbank. Lemhi Russet has averaged 34% more U.S. No. 1 tubers than Russet Burbank in 6 years of trials in five states. It was superior to Norgold Russet in yield and specific gravity in early harvest trials. In pilot plant and laboratory trials, Lemhi Russet made excellent french fries, baked well with a mealy texture, but sloughed when boiled. Lemhi Russet has a high degree of resistance to scab and net necrosis, but is susceptible to potato viruses S, X, Y, and to the leafroll virus. It is also susceptible to bruising and blackspot.ResumenUna nueva variedad, Lemhi Russet, de forma oblonga y piel tipo russet, ha sido liberada por el Departamento de Agricultura de los Estados Unidos y por las Estaciones Experimentales de Idaho, Oregon, California, Washington, y Dakota del Norte en septiembre 23 de 1980. Los tubérculos de esta nueva variedad son más grandes, 6% más alto en sólidos, 50% más bajo en azúcares reductores y 22% más alto en vitamina C que Russet Burbank. Esta variedad ha promediado 34% más de tubérculos de primera bajo los standards de Estados Unidos que Russet Burbank durante seis años de ensayos en cinco estaciones. Fue superior a Norgold Russet en rendimiento y gravedad específica en ensayos tempranos. En pruebas de laboratorio y planta piloto, Lemhi Russet demostró excelencia para papas fritas, horneado y textura harinosa, pero se deshace al hervido. Tiene gran resistencia a la sarna y necrosis en red, pero es susceptible a los virus S, X, Y y al enrrollamiento de la hoja. También es susceptible a daños mecánicos y mancha negra.

Effects of seedborne potato virus Y on Russet Norkotah performance

Research plots were established in 1996 and 1997 at Klamath Falls and Hermiston, Oregon and Tulelake, California to determine: 1) the extent of seedborne PVY spread during the growing season; 2) effects of seedborne PVY on yield and grade of Russet Norkotah; and 3) the economic consequences of varying levels of seedborne PVY infections. A series of 5 treatments evaluated initial PVY infection levels of 1 to 60% in 1996 and 1 to 98% in 1997. Virus spread occurred earlier and was more extensive at Hermiston than at Klamath Falls or Tulelake. Plants derived from PVY-free seed were nearly 100% PVY infected at early senescence at Hermiston. Comparisons of potatoes grown from PVY-free seed versus potatoes grown from seed where initial PVY infection levels were 60% in 1996 and 100% in 1997 showed seedborne PVY infection at these levels reduced U.S. No. 1 yields by an average of 40% at Hermiston, 20% at Tulelake, and 12% at Klamath Falls. Predicted total yield losses were 0.19, 0.12, and 0.08 Mg ha−1 for each percent of PVY infection at HAREC, IREC, and KES, respectively. Reductions in gross crop value were estimated at 39, 26, and 14%, respectively, based on regression analyses.

Century russet : A high-yielding fresh market cultivar with verticillium resistance

Century Russet, a high-yielding, late-maturing variety suitable for fresh tablestock use, was jointly released in 1995 by Agricultural Experiment Stations in Oregon, Idaho, Washington, Colorado, California, and Texas and the USDA Agricultural Research Service. Extremely high yields have been observed for Century Russet in variety trials conducted in Oregon and throughout the western United States under a wide range of soil and climatic conditions. Century Russet produced 40 percent higher marketable yields than Russet Burbank and 67 percent higher marketable yields than Russet Norkotah in 11 regional trials conducted over a three-year period in sevenwestern states. Uniform tuber shape, high yields of count carton sizes, and attractive tuber appearance make Century Russet well suited for the fresh market industry. It is not recommended for chipping or processing into frozen products because of low solids and dark fry color. Century Russet is highly resistant toVerticillium wilt and consistently develops less hollow heart, brown center, and other internal defects than Russet Burbank. It requires more time between vine kill and harvest than Russet Burbank for adequate tuber maturity and skin set. Bruised Century Russet tubers are susceptible to early blight andFusarium infection.

Modoc: A potato variety with bright red skin and early maturity for fresh market

Modoc is an early maturing, red-skinned, whitefleshed potato cultivar for fresh market use. The Agricultural Experiment Stations of Oregon, North Dakota, California, Idaho, and Washington jointly released Modoc in 2003. Modoc was derived from a 1989 cross of ND1196-2R and ND2225-1R performed at North Dakota State University. Modoc retains bright skin color in storage and is suited for marketing directly from the field or storage. It produces slightly lower total yield than Red LaSoda or Dark Red Norland, but higher marketable yield and more desirable tuber size and shape. Modoc tubers seldom exhibit growth cracks, secondary growth, hollow heart or other external or internal defects. Dry matter content of Modoc tubers is similar to Dark Red Norland and Red LaSoda (18.9% compared to 18.8% and 17.7%, respectively). Culinary quality of Modoc was rated equal to Dark Red Norland and Red LaSoda for boiling and microwaving preparation methods. Modoc tubers are similar to standard varieties in sugar, vitamin C, and glycoalkaloid (4.5 mg/100 g) concentration. Modoc foliage clearly expresses PVY symptoms and has not demonstrated high susceptibility to viral or fungal diseases during a decade of seed production and evaluation.ResumenModoc es un cultivar de papa de madurez precoz, piel roja y de uso en fresco. Las Estaciónes Experimentales de Oregon, North Dakota, California, Idaho y Washington han liberado conjuntamente el cultivar Modoc en el 2003. Modoc deriva de un cruzamiento de ND1196-2R y ND2225-1R realizado en la Universidad del Estado de North Dakota en 1989. Modoc retiene el color rojo brillante de la piel en almacenamiento y es apropiada para su comercialización directa a partir del campo o del almacén. Tiene rendimientos totales ligeramente menores que la Red LaSoda o la Dark Red Norland, pero mayor cantidad de tubérculos comercializables y de forma y tamaño preferidos. Los tubérculos de Modoc raramente exhiben rajaduras de crecimiento, crecimiento secundario, corazón vacío u otros defectos internos y externos. El contenido de materia seca de Modoc es similar al de Dark Red Norland y Red LaSoda (18.9 comparado con 18.8 y 17.7 por ciento, respectivamente). Las cualidades culinarias de Modoc son iguales a las de Dark Red Norland y Red LaSoda para hervido y métodos de preparación en microondas. Los tubérculos de Modoc son similares a los de las variedades estándar en la concentración de azúcares, vitamina C y glicoalcaloides (4.5 mg/100 g). El follaje de Modoc muestra claramente síntomas de PVY pero no ha demostrado alta susceptibilidad a enfermedades virales o fungosas durante la década de producción y evaluación de semilla.

Winema: An Early Maturing, Red- Skinned Cultivar for Fresh Market

Winema, an early maturing, red-skinned cultivar for fresh market use, was jointly released in 2000 by the Agricultural Experiment Stations of Oregon, North Dakota, California, Idaho, and Washington. Winema was evaluated in irrigated trials in Oregon and California from 1990 to 2000 and in the Western Regional Trial in 1995,1997, and 1998. Winema has produced lower total yields than Dark Red Norland and Red LaSoda at most locations, but similar or higher marketable yields and significantly fewer culls. In 20 location-years of replicated Oregon and California trials, Winema produced 108% and 99% of marketable yields of tubers under 280 g compared with Red LaSoda and Dark Red Norland, respectively. Similarly, in 23 location-years of The Western Regional Trial in 6 western states, Winema produced 109% and 92% of marketable yields of tubers under 280 g compared with Red LaSoda and Dark Red Norland, respectively. Winema tubers are smooth-skinned with shallow eyes. Winema’s bright red color does not fade appreciably in storage. Winema is susceptible to potato virus Y (PVY). Foliar symptoms of PVY are difficult to detect visually.

Mazama : An early maturing, bright red-skinned cultivar for fresh market

Mazama, an early maturing red-skinned cultivar for fresh market use, was jointly released in 2000 by the Agricultural Experiment Stations of Oregon, North Dakota, California, Idaho, and Washington. Mazama was tested in irrigated trials in Oregon from 1990 to 2000 and in the Western Regional Trial in 1994, 1995, and 1997. Mazama produces lower total yields than Dark Red Norland and Red LaSoda, but similar marketable yields with a high percentage of small, high-value tubers and significantly fewer culls. In 22 location-years of replicated Oregon and California trials, Mazama produced 40% and 26% higher marketable yields of U.S. #1s under 280 g than Red LaSoda and Dark Red Norland, respectively. In three years of replicated trials in six western states, Mazama produced 115% and 102% of marketable yields of U.S. #1s under 280 g compared with Red LaSoda and Dark Red Norland, respectively. Mazama tubers are smooth skinned and shallow eyed. Mazama’s bright red color does not fade in storage. Mazama is less susceptible to potato virus Y than Dark Red Norland or Red LaSoda.

The Potato Association of America 75th Annual Meeting Spokane, Washington, U.S.A.

NOTE: These minutes make references to several reports. Complete versions of most of these reports can be found elsewhere in this issue of APJ. President Latter called the meeting to order and welcomed all to Spokane. He then called for any additions to the agenda. There were none. However, Murphy asked those assembled to sign a card of condolence to Geddes Simpson whose wife had recently died. Geddes Simpson was the long time editor of APJ. President Lauer then asked for any additions or corrections to the minutes of the 1990 Executive Committee meeting as published in APJ 67:875-822. There were none.

The application of an excised root assay for the determination of susceptibility or resistance to root-knot nematodes (Meloidogyne spp. Goeldi) in potatoes (Solanum spp. L.)

Excised roots of six potato selections were challenged with egg inoculum of fourMeloidogyne species:M. chitwoodi, M. javanica, M. incognita, andM. hapla. The dual cultures were established under aseptic conditions in 60 × 15 mm petri plates on a defined agar medium. Egg hatch occurred within one week and galling within four weeks at incubation temperature of 24°C. All six potato selections, Russet Burbank, White Rose, PAS 3065,S. sparsipilum 365343.A19-12,S. sparsipilum ×S. phureja 856D68-1, and NDTX8731-1R supported reproduction of all fourMdoidogyne species. Corresponding greenhouse tests were run with eachin vitro experiment to establish the efficacy of this screening technique compared to greenhouse methods. Results from the greenhouse assays had less variation within cultivar treatment than did the results from thein vitro assays. Thein vitro assay, however, may be conducted with less labor, time, and greenhouse facility management.CompendioSe expusieron raíces cortadas de seis selecciones de papa al inóculo (huevos) de cuatro especies deMeloidogyne: M. chitwoodi, M. javanica, M. incognita yM. hapla. Cultivos duales fueron establecidos bajo condiciones asépticas en platos de petri de 60 × 15 mm con un medio definido de agar. La eclosión de los huevos se produjo en una semana y la formación de agallas en cuatro semanas a una temperatura de incubación de 24°C. Las seis selecciones de papa, Russet Burbank, White Rose, PAS 3065,S. sparsipilum 365343.A19-12,S. sparsipilum ×S. phureja 856D68-1 y NDTX8731-1R permitieron la reproduction de las cuatro especies deMeloidogyne. Las pruebas correspondientes de invernadero fueron llevadas a cabo con cada experimentoin vitro para establecer la eficacia de esta técnica de evaluation y selectión en comparación con los métodos de invernadero. Los resultados de las pruebas en el invernadero variaron menos dentro del tratamiento de cultivares que los resultados obtenidos de las pruebasin vitro. Sin embargo, la pruebain vitro puede conducirse con menos trabajo, tiempo y manejo de las instalaciones de invernadero.