Defender: A High-Yielding, Processing Potato Cultivar with Foliar and Tuber Resistance to Late Blight

American Journal of Potato Research, Jan/Feb 2006 by Novy, R G, Love, S L, Corsini, D L, Pavek, J J, Et al

ABSTRACT

The potato cultivar Defender is high-yielding, white-skinned, and notable for having foliar and tuber resistance to late blight infection caused by Phytophthora infestans (Mont.) de Bary, It was released in 2004 by the USDA-ARS and the agricultural experiment stations of Idaho, Oregon, and Washington. Defender is suitable for processing into french fries and other frozen potato products directly from the field or from storage. Defender also may be used for fresh markets in regions such as California, where cultivars with long tubers and white skin are traditionally grown. Resistances to late blight and other potato diseases make Defender an ideal candidate for organic potato production. Defender consistently produced greater total and U.S. No. 1 yields than 'Russet Burbank' in Idaho trials. In early harvest trials conducted in the western U.S., average total yields of Defender were 17% and 23% greater than yields for 'Ranger Russet' and 'Shepody', respectively. In full-season trials conducted in the western U.S., Defender averaged 10% and 15% higher yields than Ranger Russet and Russet Burbank, respectively. Specific gravity of Defender is consistently high, with values comparable to those of Ranger Russet; tuber ascorbic acid (Vitamin C) levels are also high. In addition to late blight, Defender also is resistant to tuber early blight (Alternaria solani, (Ellis & G. Martin), L.R. Jones & Grout), potato virus X, and net necrosis; it has moderate levels of resistance to Verticillium wilt (Verticillium dahliae, Kleb), pink rot, foliar early blight, corky ringspot, and Erwinia soft rot. Defender is susceptible to scab (common and powdery) and potato leafroll virus; it has moderate susceptibility to dry rot (Fusarium spp.) and potato virus Y. Susceptibilities to internal necrosis, tuber greening, and blackspot bruise also have been noted, but may be minimized through cultural and harvest practices.

RESUMEN

Defender es un cultivar de papa de alto rendimiento, piel blanca y excelente por su resistencia al tizoói tardío causado por Phytophthora infestans (Mont.) de Bary, tanto a la infección foliar como a la de los tubércules. Ha sido liberada el 2004 por USDA-ARS y las Estaciones Experimentales Agrícolas de Idaho, Oregon y Washington. Defender es apropiado para el procesamiento de papa frita y otros productos congelados de papa, directamente del campo o del almacén. Defender puede también ser usado en regiones como California, donde se cultivan tradicionalmente variedades de tubércules alargados y piel blanca. La resistencia al tizón tardío y otras enfermedades de la papa hace de Defender un candidato ideal para la producción orgánica. Defender tuvo consistentemente un mayor rendimiento de tubérculos de grado "US No. 1" que Russet Burbank en pruebas en Idaho. En ensayos de cosecha temprana realizados en el oeste de EUA, el promedio de rendimiento total de Defender fue de 17 y 23% mayor que el de las variedades Ranger Russet y Shepody respectivamente. En ensayos de ciclo completo realizadas en el oeste, Defender tuvo rendimientos 10 y 15% mayores que Ranger Russet y Russet Burbank respectivamente. El peso específico de Defender es consistentemente alto, con valores comparables a los de Ranger Russet y los niveles de ácido ascórbico (Vitamina C) son también altos. Además de ser resistente al tizón tardío, Defender es también resistente al tizón temprano (Alternaria solani (Ellis & G. Martín) L. R. Jones & Grout), Virus X de la papa y necrosis en red. Tiene niveles moderados de resistencia a marchitez por Verticillium (Verticillium dahliae Kleb.), pudrición rosada, tizón foliar temprano, mancha corchosa en anillo y pudrición blanda causada por Erwinia. Defender es susceptible a la sarna (común y polvorienta) y al virus del enrollamiento; tiene moderada susceptibilidad a la pudrición seca (Fusarium spp.) y al virus Y de la papa. También se ha notado susceptibilidad a necrosis interna, verdeamiento del tubérculo y mancha negra, pero estas pueden minimizarse a través de prácticas culturales.

Accepted for publication 15 June 2005.

ADDITIONAL KEY WORDS: Solanum tuberosum, variety, breeding, vitamin C, organic production

INTRODUCTION

Defender was first grown and selected in the field at Aberdeen, ID, in 1993 where it was given the clonal designation A90586-11. It originated from a hybridization by J. J. Pavek in 1990 between breeding clone KSA195-90 and Ranger Russet. KSA195-90 was a selection made at Aberdeen, ID, from true potato seed received from the Polish Plant Breeding and Acclimatization Institute, Radzikow, Poland. KSA195-90 initially was used in the Aberdeen Potato Breeding Program as a source of resistances to potato viruses S, X, Y and potato leafroll virus (PLRV). Subsequently, it and other selections with Polish germplasm in the ancestry were identified as sources of resistance to the aggressive, metalaxyl-resistant genotypes of Phytophthora infestans that were identified in the USA in the early 1990s (Corsini et al. 1999). The original source of late blight resistance found in KSA195-90 is unclear in that a diverse number of Mexican and South American wild and cultivated species are in its background. Corsini et al. (1999) speculated that this diversity may contribute to durable resistance, although R-genes from Solanum demissum are likely present as well. Potato cultivars in the pedigree of Defender (Figure 1) include the North American cultivars Butte (Pavek et al. 1978), and Norgold Russet (Johansen 1965), as well as the European cultivars Duet, Malchow St., Swit, and Hochprozentige.