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Utilization of potato genetic resources in variety development

  • J. J. Pavek
  • D. L. Corsini
Article

Abstract

Potato varieties of Europe, widely grown prior to the late blight epidemic of the 1840s, were apparently derived mainly from ChileanSolanum tuberosum Group (Gp) Tuberosum and with contributions from Gp Andigena. A small number of these old varieties had field resistance and consequently survived the late blight. These survivors, along with a limited number of 19th and early 20th century introductions, provided the very narrow genetic base for our modern potato variety development. Beginning in the first half of the 20th century, resistance to diseases and pests from exotic species and primitive relatives was backcrossed into the existing parental stocks, with little improvement in broadening of the genebase. By the 1980s, 77% of European and somewhat fewer North American varieties had genes, derived by backcrossing, fromS. demissum (late blight resistance) and Andigena (resistance to cyst nematode). Broadening of the Tuberosum genebase was undertaken in 1959 by creating long-day adapted Neo-Tuberosum (N-T) from large populations of Andigena. This took six or more cycles of recurrent mass selection. Simmonds, in England, was the first to begin this work, followed shortly after by Plaisted, in the U.S., and Tarn, in Canada. Varieties with N-T in their pedigrees include the New York releases “Rosa”, which is 50% N-T, and “Eva”, 25% N-T. The Tuberosum genebase has also been broadened with diploid Gp Phureja resulting in the releases of “Yukon Gold,”with yellow flesh and high internal quality, and “NorValley,”a chipper with resistance to cold sweetening. Over 5000 accessions of about 150 wild species are available to breeders from the U.S. Department of Agriculture, National Research Support Project 6 (NRSP-6) genebank. Many of these accessions have been evaluated for resistance to diseases and pests as well as other important traits. Six genebanks in other countries also have many accessions for breeders. These seven collections are a great source of valuable traits for breeding, but remain under-utilized, mainly because of the time and additional resources required in eliminating the “wildness”characters associated with the desired traits. “Pre-breeding”is needed to help breeders utilize the many needed genes and alleles in the wild species. There now are two projects with pre-breeding as an objective in the U.S., one at Madison, WI, and the other at Prosser, WA. Resistance to cold sweetening (low sugar build up in cold storage) has been backcrossed from several wild species into the Tuberosum background, as has resistance to late blight, the Columbia rootknot nematode, and the potato leafroll virus (PLRV). Resistance to potato virus Y (PVY) and PLRV obtained from N-T has been incorporated into Tuberosum parental stocks. Durable resistance to late blight in Polish breeding stocks, withS. demissum andS. stoloniferum background, and in improved Bolivian and Peruvian Andigena has also been utilized by North American programs.

Additional key words

Genebanks germplasm disease/pest resistance potato breeding 

Resumen

Las variedades de papa de Europa, cuyo crecimiento se difundió antes de la epidemia del tizón tardío de 1840, en apariencia se derivaron principalmente de la papa chilena Solanum tuberosum grupo (Gp) Tuberosum con contribución del Gp Andigena. Un pequeño número de esas var-iedades antiguas tenía resistencia de campo y, en consecuencia, logró sobrevivir a la epidemia. Esas sobrevivientes, conjuntamente con un número limitado de introducciones realizado durante los siglos 19 y 20, proporcionaron la muy estrecha base genética para nuestro moderno desarrollo de variedades de papa. En la primera mitad del siglo 20 se comenzaron los retrocruzamientos para resistencia a enfermedades y plagas desde las especies exóticas y sus parientes primitivos al stock existente de progenitores, con pequeños progresos en el ensanchamiento de la base genética. Para 1980, el 77 por ciento de las papas europeas y unas pocas de Norteamérica tenían genes, derivados de retrocruzamientos, de S. demissum (con resistencia al tizón tardío) y Andigena (resistencia al nematodo del quiste). El ensanchamiento de la base genética de Tuberosum se emprendió en 1959 con la creación de una Neo-Tuberosum (N-T) adaptada a dias largos, a partir de grandes poblaciones de Andigena. Este proceso tomó seis o más ciclos de selección masiva recurrente. Simmonds, en Inglaterra, fue el primero en iniciar dichos trabajos, seguido de cerca por Plaisted, en los Estados Unidos, y Tarn en Canadá. Las variedades con N-T en sus pedigrees incluyen la liberatión de “Rose” en Nueva York, la cual contiene 50% de N-T, y Eva, con 25% de N-T. La base genética de Tuberosum también ha sido ampliada con el diploide del Gp Phureja, lo cual ha resultado en la liberación de “Yukon Gold”, con pulpa amarilla y gran calidad interna, y “Nor Valley”, para hojuelas, con resistencia al endulzamiento en frío. Alrededor de 4300 accesiones de más de 100 especies silvestres están disponibles para los mejoradores en el banco genético del Proyecto 6 Apoyo a los Investigadores Nacionales (NRSP-6) del Departamento de Agricultura de los Estados Unidos. Muchas de esas accesiones han sido evaluadadas por su resistencia a enfermedades y plagas así como por otras importantes características. Seis bancos genéticos en otros países también tienen muchas accesiones disponibles para los mejoradores. Estas siete colecciones son una gran fuente de invalorables características para fitomejoramiento, pero permanecen subutilizadas, principalmente debido al tiempo y los recursos adicionales requeridos para eliminar las caracteristicas de “rusticidad” asociadas con los caracteres deseados. El “premejo-ramiento” es necesario para ayudar a los fitomejoradores a utilizar los múltiples genes y alelos más útiles de las especies silvestres. En los Estados Unidos existai actualmente dos proyectos cuyo objetivo es el premejoramiento, uno está en Madison, WI, y el otro en Prosser, WA. La resistencia al endulzamiento en frío (formatión de poco azúcar durante al almacenamiento en frío) ha sido retro-cruzada a la base de Tuberosum a partir de diversas especies silvestres, según tengan resistencia al tizón tardío, al nematodo del nódulo de la raíz de Columbia o al virus del enrollamiento de la hoja de papa (PLRV). Las resistencia al virus Y de la papa (PVY) y a PLRV obtenida de N-T ha sido incorporada al sotck de progenies de Tuberosum. Los programas de Norteamérica también están usando resistencia duradera al tizón tardío en los stocks de selectión de Polish, con base en S. demissum y S. stoloniferum, y a una Andigena mejorada boliviana y peruana.

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Authors and Affiliations

  1. 1.USDA-ARSUniversity of Idaho R & E CtrID

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