H. De Jong

Yield potential and genotype-environment interactions of tetraploid-diploid (4x-2x) potato hybrids

Six advanced selections of a population of 4x-2x hybrids were tested and compared with six well-adapted Group Tuberosum cultivars under field conditions at four locations in Canada over two years.Three 4x-2x hybrids produced a total and a marketable yield which was equal to or higher than that of most cultivars over eight environments. For marketable yield considerable differences existed between genotypes in the amount of variation occurring over the eight environments. Both groups of genotypes contained clones with low and high variation for marketable yield.Analysis of genotype-environment (GE) interactions for marketable yield indicated that all genotypes differed from each other in their responses to the environmental effects. However, there was no clear distinction between the group of 4x-2x hybrids and the group of cultivars for the GE interaction patterns. It appears that the heterosis of the 4x-2x hybrids is the result of a broadening of the genetic base of Group Tuberosum breeding stocks by the incorporation of germ plasm from the primitive diploid South American cultivars. Development of improved diploid parents is necessary in order to achieve the full potential of the 4x-2x hybridization method.ResumenSeis selecciones avanzadas de una población de híbridos 4x - 2x se evaluaron y compararon con seis cultivares del Gp. Tuberosum adaptados bajo condiciones de campo durante dos años en cuatro localidades de Canadá.Tres hibridos 4x - 2x dieron rendimientos totales y comerciales iguales o mayores que la mayoría de los cultivares sobre los ochos ambientes. Se encontraron diferencias genotípicas marcadas para el rendimiento comercial con respecto a la variación ambiental. Ambos grupos de genotipos tuvieron clones con alta y baja variación con respecto a su rendimiento comercial.El análisis sobre interacción genotipo-ambiente (GE) para el rendimiento comercial indicó que todos los genotipos tienen respuesta diferencial a los efectos ambientales. Sin embargo, no hubo clara distinción entre los híbridos del grupo 4x -2x el grupo de cultivares con respecto a su interacción con el ambiente (GE). Es de esperar que la heterosis de los híbridos 4x -2x sea el resultado de la amplicación de la base genética del Grupo Tuberosum debido a la incorporación de germoplasma proveniente de cultivares primitivos diploides de Sudamérica. Es necesario el mejoramiento de los progenitores diploides para alcanzar el máximo potencial del método de hibridación 4x - 2x.

The germplasm release of F87084, a fertile, adapted clone with multiple disease resistances

F87084 is a germplasm release that has been developed by conventional breeding methods and can be traced back to very diverse germplasm sources. This clone has excellent female fertility, round-oval tubers and is well adapted to Eastern Canada. The vine maturity is slightly later than that of Kennebec, and the mean marketable yield is 78% of Kennebec. The specific gravity, boil, bake and chip scores are somewhat lower than Kennebec. F87084 is resistant to late blight,Verticillium dahliae, early blight, and the pathotypes of wart occurring in Newfoundland. F87084 has extreme resistance to PVYo and PVX. It is also resistant to the potato cyst nematode pathotype Ro1. Progeny analyses indicate that F87084 is duplex for the genes controlling extreme resistance to PVX as well as resistance to the potato cyst nematode (Ro1).ResumenF87084 es un germoplasma liberado, que ha sido desarrollado con métodos convencionales de mejoramiento y que puede ser referido a muy diversas fuentes de germoplasma. Este clon tiene excelente fertilidad femenina, tubérculos redondo-ovalados y está bien adaptado a la zona este de Canada. La madurez del follaje es ligeramente más tardía que la de Kennebec. Asimismo, su rendimiento comercial más bajo es 78% superior al de Kennebec. Los valores de su gravedad específica, cocción, horneado y fritura en hojuelas son un poco más bajos que Kennebec. El clon F87084 es resistente al tizón tardío,Verticillium dahliae, tizón temprano y a los patotipos de verruga encontrados en Newfoundland. F87084 posee resistencia extrema a PVY y PVX. También es resistente al patotipo Ro 1 del nematodo del quiste de la papa. El análisis de la progenie indica que el clon F87084 posee alelos en conditión duplex para los genes que controlan la resistencia extrema a PVX así como la resistencia al nematodo del quiste de la papa (Ro1).

Development and characterization of an adapted form ofdroopy, a diploid potato mutant deficient in abscisic acid

A cultivated diploid potato breeding population has been selected for adaptation to growing, tuberizing (under relatively long days), and storing (including long dormancy) under New Brunswick conditions. In this population, a mutant was discovered that appeared similar to the earlier describeddroopy mutant, which is deficient in abscisic acid and is unable to regulate water loss from its leaves. The physiology and genetics of the newly discovered mutant were studied and compared in detail with the description ofdroopy. This mutant has a longer tuber dormancy than the originaldroopy. In families segregating fordroopy and normal, similar dormancies and endogenous abscisic acid levels in tubers were observed betweendroopy and normal genotypes. The effect of the mutant gene appears to be tissue specific, affecting aboveground plant parts only. A test for allelism indicated that this mutant is allelic todroopy. Classical linkage analyses confirmed previously reported close linkage between theDr (droopy) and theS (incompatibility) loci. TheDr locus has been mapped in this study to the top of chromosome I. Several test crosses indicated reciprocal differences in the segregation ratios betweendroopy and normal In keeping with thedroopy (drdr) genotype, drought-stressed leaves of the mutant were incapable of increasing abscisic acid production compared to the normal. This mutant, with its apparent developmentally restricted expression, may be useful in elucidating the genetic and physiological processes associated with such major events as tuberization, response to drought stress and tuber dormancy.

Ac brador: a new late-maturing cultivar with a high degree of field resistance to late blight

AC Brador is a late maturing yellow-fleshed cultivar. The vine maturity is slightly later than Russet Burbank. The oblong tubers have a specific gravity which is slightly higher than Kennebec. The boil and bake quality of AC Brador is similar to Kennebec. The mean French fry quality of AC Brador is below that of Russet Burbank but still in the acceptable range. This cultivar has extremely high field resistance to late blight resistance to verticillium wilt and early blight, a relatively high resistance to PLRV, and a moderate resistance to PVYand rhizoctonia.CompendioAC Brador es un cultivar tardío de came amarilla. La maduración del follaje es ligeramente más tardía que la de Russet Burbank. Los tubérculos son oblongos y tienen una gravedad específica ligeramente superior ala de Kennebec. La calidad a la cocción y al horneo es similar a la de Kennebec. La calidad promedio de fritura a la francesa está por debajo de la de Russet Burbank, pero aún en el rango aceptable. Este cultivar tiene una resistencia de campo extremadamente alta al tizón tardío, resistencia a la marchitez por verticilhium y al tizõn temprano, resistencia relativamente alta al PLRV, y una resistencia moderada al PVY, y a ha rhizoctoniasis.

Ac novachip: a new potato cultivar with excellent chip quality after long storage and reconditioning

AC Novachip is a smooth, white-skinned potato cultivar with oval to oblong tubers and a maturity similar to Kennebec. It has excellent chip quality, especially after long storage and reconditioning. The boil and bake quality is similar to Kennebec; the specific gravity is higher than Kennebec but lower than Atlantic. AC Novachip has moderate resistance to common scab and PVY.CompendioAC Novachip es un cultivar de papa suave, de piel blanca, con tubérculos ovales a oblongos y con una maduración semejante a la de Kennebec. Tiene excelente calidad de fritura a la francesa, especialmente después de un almacenamiento y reacondicionamiento prolongado. La calidad a la cocción y al horneado es similar a la de Kennebec; Ia gravedad específica es más alta que la de Kennebec, pero más baja que la de Atlantic. AC Novachip tiene resistencia moderada a la sarna común y al PVY.

Ac chaleur: a new early-maturing cultivar with excellent table quality

AC Chaleur is adapted as a second early cultivar in Eastern Canada. It has smooth, bright round-oval tubers with excellent table quality. When harvested at 70-80 days from planting, AC Chaleur tends to outyield Superior. This yield advantage decreases at later harvest times. AC Chaleur has resistance to PVYand moderate resistance to common scab.CompendioAC Chaleur está adaptada como segundo cultivar precoz en el este de Canadá. Tiene tubérculos suaves, redondos a ovales, y brillantes de excelente calidad para Ia mesa. Cuando son cosechados a los 70-80 días del sembrío, el AC Chaleur tiende a sobrepasar el rendimiento de Superior. Esta ventaja en el redimiento disminuye cuando La cosecha se lleva a cabo más tarde. AC Chaleur tiene resistencia al PVY, y resistencia moderada a la sarna común.

Ac belmont: a new early-maturing potato cultivar with short dormancy

AC Belmont is adapted as a second early cultivar in Eastern Canada. It has a short dormancy. The white-skinned round oval tubers size and bulk early, but more similar to Superior than to Jemseg. The specific gravity of AC Belmont is lower than Superior. When boiled, the tubers of AC Belmont have a good, somewhat moist texture; when baked the texture of AC Belmont is relatively dry. AC Belmont is highly resistant toVerticillium albo-atrum, moderately resistant to PVY,Fusarium coeruleum, F. sambucinum f.6. andRhizoctonia solani.CompendioAC Belmont está adaptada como un segundo cultivar precoz al este del Canada. Tiene un periodo de reposo corto. Los tubérculos redondos ovales de piel blanca, crecen y cargan precozmente, pero más similarmente a Superior que ajemseg. La gravedad específica de AC Belmont es menor que la de Superior. Cuando se les sancocha, los tubérculos de AC Belmont tienen una buena textura, algo húmeda; cuando se le hornea, la textura de AC Belmont es relativamente seca. AC Belmont es altamente resistente a Verticillium albo-alrum, moderadamente resistente al PVY, aFusarium coeruleum,F sambucinum f.6., y aRhizoctonia solani.

Donna: A yellow-fleshed potato cultivar with potential in export seed markets

Donna is a smooth, yellow-skinned, yellow-fleshed potato cultivar of Kennebec maturity. It has significant levels of resistance to Verticillium wilt, PVX, PVY and to the North American pathotype of the potato cyst nematode. Adaptation trials conducted in several countries indicate Donna may have potential in the export seed market.CompendioDonna es un cultivar de papa de piel suave y amarilla, con carne amarilla de maduración semejante a la del cultivar Kennebec. Tiene niveles significativos de resistencia a la marchitez porVerticilium, al PVX y PVY, y al patotipo norteamericano del nematodo del quiste. Los ensayos de adaptación conducidos en varios países indican que Donna puede tener potencial en el mercado de semilla de exportación.