F. I. Lauer

Insect resistance in potatoes: sources, evolutionary relationships, morphological and chemical defenses, and ecogeographical associations.

SummaryThe past 25 years, 1686 potato accessions, representing 100 species in the genus Solanum L., subgenus Potatoe, section Petota, were evaluated for field resistance to one or more of the following insect pests: green peach aphid, Myzus persicae (Sulzer); potato aphid, Macrosiphum euphorbiae (Thomas); Colorado potato beetle, Leptinotarsa decemlineata (Say); potato flea beetle, Epitrix cucumeris (Harris); and potato leafhopper, Empoasca fabae (Harris). Accessions highly resistant to green peach aphid were identified within 36 species, to potato aphid within 24 species, to Colorado potato beetle within 10 species, to potato flea beetle within 25 species, and to potato leafhopper within 39 species. Resistance levels were characteristic within Solanum species. Insect resistance appears to be a primitive trait in wild potatoes. Susceptibility was most common in the primitive and cultivated Tuberosa. Insect resistance was also characteristic of the most advanced species. The glycoalkaloid tomatine was associated with field resistance to Colorado potato beetle and potato leafhopper. Other glycoalkaloids were not associated with field resistance at the species level. Dense hairs were associated with resistance to green peach aphid, potato flea beetle, and potato leafhopper. Glandular trichomes were associated with field resistance to Colorado potato beetle, potato flea beetle, and potato leafhopper. Significant correlations between insect score and altitude of original collection were observed in six of thirteen species. Species from hot and arid areas were associated with resistance to Colorado potato beetle, potato flea beetle, and potato leafhopper. Species from cool or moist areas tended to be resistant to potato aphid.

Evaluation of Tuber-Bearing Solanum Species for Nitrogen Use Efficiency and Biomass Partitioning

Modern potato cultivars (Solanum tuberosum L.) require high rates of fertilizer nitrogen (N). This practice is costly and can pose a serious threat to surface and groundwater. Previous evaluation of wild potato germplasm demonstrated the existence of species capable of producing high total biomass under low N conditions, with the ability to make maximum use of added N. Therefore, a two-year field experiment was conducted in 1994 and 1995 to investigate the response of selected wild potato accessions and their hybrids with the haploid USW551 (USW) to low and high N environments. The haploid USW and cultivars Russet Burbank, Red Norland, and Russet Norkotah were also included in the study. Uniform propagules and seedlings from the variousSolanum species were transplanted to a Hubbard loamy sand (Udic Haploboroll) at Becker, Minn. and were subjected to two N treatments: 0 and 225 kg N ha-1. At harvest, total dry biomass of wild and hybrid potato germplasm was equal to or higher than that of the cultivars. However, cultivar biomass partitioning was 1% to roots, 15% to shoots, 0% to fruits, and 84% to tubers, whereas wild potato species partitioned 18% to roots plus nontuberized stolons, 52% to shoots, 23% to fruits, and only 7% to tubers. Hybrids were intermediate, allocating 9% of their biomass to roots plus nontuberized stolons, 39% to shoots, 14% to fruits, and 38% to tubers. Nitrogen use efficiencies for many of the species and crosses were comparable to that for Russet Burbank and greater than those for Red Norland and Russet Norkotah. Of the wild species tested,S. chacoense accessions had the highest biomass accumulation and N uptake efficiencies and may be the best source of germplasm for improving NUE in a potato breeding program.

Breeding behavior of yield components and hollow heart in tetraploid-diploid vs. conventionally derived potato hybrids

SummaryA factorial mating design with six 4x cultivars as stylar parents mated to three groups of pollen parents (4x cultivars, 4x high protein selections, and 2x S. phureja) was used to study breeding behavior of yield, tuber set, marketable yield and hollow heart in potatoes. Mean yield for the 4x-2x hybrids was equivalent to that of their cultivar parents although yield components, tuber set and average tuber size, were greater and less, respectively, than the cultivar parents. High estimates of general combining ability were found in both pollen and stylar parents for yield, tuber set, marketable yield, number of marketable tubers and hollow heart in all three hybrid populations. Specific combining ability estimates were significant only for yield and hollow heart. Frequency of white-fleshed 4x-2x progeny of five heterozygous yellow-fleshed 2x phureja genotypes was used to confirm cytological identification of a first division restitution mechanism operative in the 2x parents. Although three of these phureja genotypes generated high-yielding progeny, two others produced 4x-2x progeny with mean yield similar to that of hybrids among 4x cultivars.

A possible genetic source for chipping potatoes from 40 F storage

An interspecific hybrid ofS. phureja x USW1, a haploid of Katahdin, produced acceptable potato chips when processed directly from 40 F (4.5 C) storage during 3 years of testing. It was crossed with 11 interspecific hybrids. Tubers from these progenies were stored for 5 weeks at 40 F and then chipped immediately for 55 seconds in vegetable oil maintained at 375 F (190 C). Of 645 seedlings tested, chip color was acceptable in 17 and variable in 18. A group of 600 seedlings fromS. tuberosum parents treated comparably produced black-colored chips without exception.ResumenUn hibrido interspecifico deS. phureja x USW1 (haploide de la variedad Katahdin) produjo papas astilladas aceptables.Estas papas fueron procesadas directamente de un almacen cuya temperatura fue mantenida a 4.5 C. Las pruebas fueron hechas durante tres años.Este híbrido fue cruzado con once hybridos interespecificos. Tuberculos de estas progenies fueron almacenadas durante cinco semanas a 4.5 C y luego procesadas durante 55 segundos en aceite vegetal mantenido a 190 C. En una prueba de 645 plantas provenientes de estos cruces, se encontró que el color de las papas astilladas era aceptable en 17 clones y variable en 18 clones. Un grupo de plantas procesadas del mismo modo, pero proveninetes deT. tuberosum sin exepción produjeron papas astilladas de color negro.

First clonal generation potato progeny performance at two Minnesota locations

In a majority of potato breeding programs in the United States, first clonal generation progenies are propagated from tubers of seedlings grown in greenhouses or screenhouses. Initial selections for horticultural characters are made among first clonal generation plants. Since such plants are propagated from seed tubers considerably smaller than those used in subsequent propagations, the performance of these selections may (lifter in later clonal generations. Krantz et al. (2. 3) observed a delay in maturity of first clonal generation plants, associated with reduced seed tuber size. They further noted that these effects could be carried over into the second clonal generation due to smaller tubers produced in the first clonal generation. Evaluation of potato progeny performance at several locations has been conducted primarily with second clonal generation or older material. Sanford (4) in comparing progeny performance for yield at three locations obtained high estimates of progeny by location interaction. Gates (1) compared the effectiveness of selection at a single location with subsequent performance at several locations. When selection was made at a single location, similar advance in subsequent performance was reported at all locations. Substantial advances by selection were obtained for total yield, U. S. No. 1 yield and tuber length. In the Minnesota potato breeding program, initial selections in first clonal generation progenies have been made at Castle Danger in the northeastern part of the state. The major commercial productmn area, however, is the Red River Valley in the northwestern part of the state. To obtain information on association of progeny and clonal performance in the two areas, the performance of unselected first clonal generation progenies was compared at Castle Danger (Northeast Minnesota) and Crookston (Northwest Minnesota). Concurrent studies were also made on the association of seed tuber size and subsequent field performance, and tuber set in the greenhouse and field.

Relative resistance of the potato cultivar krantz to common scab caused byStreptomyces scabies as determined by cluster analysis

Twenty potato breeding selections and five potato cultivars (25 clones) were evaluated in replicated field plots for their resistance to common scab caused byStreptomyces scabies, at Presque Isle, ME and Cranesville, WV in 1993. At harvest, all tubers in each plot were individually scored for the surface area covered (0=0% to 5>75%) and for lesion type (0=no lesions to 5=pitted lesions). The individual tuber scores for either surface area covered or lesion type for each plot were totaled and divided by five times the number of tubers to create an index of surface area covered (SAI) or lesion type (LI), respectively. Clonal mean SAI ranged from 0.05 to 0.96 in Maine and 0.21 to 0.89 in West Virginia. Clonal mean LI ranged from 0.06 to 1.0 in Maine and 0.48 to 1.0 in West Virginia. There were significant differences among clones for SAI and LI. Clones were clustered on mean SAI and LI in ME and WV. The clones clustered into four groups. The resistance of Krantz and two breeding selections, B0348-2 and B0339-1, was similar to Ontario.CompendioVeinte selecciones de mejoramiento de papa y cinco cultivares (25 clones) fueron evaluados, en 1993, en parcelas de campo con repeticiones, para su resistencia a la sarna común causada por Streptomyces scabies, en Presque Isle, ME y Cranesville, WV. Al momento de la cosecha, todos los tubérculos en cada parcela fueron calificados individualmente por el área de superficie cubierta (0=0 % a 5>75 %) y por el tipo de lesión (0=sin lesiones a 5=lesiones profundas). Las calificaciones individuates por tubérculo, tanto por área de superficie cubierta como por el tipo de lesiones, para cada parcela, fue totalizada y dividida por cinco veces el número de tubérculos, para crear un indice de área de superficie cubierta (SAI) o de tipo de lesión (LI), respectivamente. El promedio clonal del SAI varió de 0.05 a 0.96 en Maine, y de 0.21 a 0.89 en West Virginia. El promedio clonal del LI varió de 0.06 a 1.0 en Maine, y de 0.48 a 1.0 en West Virginia. Hubo diferencias significativas entre los clones, para SAI y LI. Los clones fueron agrupados de acuerdo al promedio de SAI y LI en ME y WV. Los clones se agruparon en cuatro grupos. La resistencia de Krantz y dos selecciones de mejoramiento, B0348-2 y B0339-1, fue similar a la de Ontario.

Screening of exotic potato germplasm for nitrogen uptake and biomass production

Exotic potato germplasm may contain useful traits for improving nitrogen (N) use efficiency in cultivated potatoes (Solanum tuberosum L.). The objective of this study was to evaluate a “mini” core collection of wild germplasm for biomass production, N uptake, and N use efficiency. A field study was conducted during the 1993 growing season on a loamy sand soil at Becker, Minnesota. Uniform transplants for 39 wild accessions and 3 varieties were grown under greenhouse conditions, and after 40 days, they were transplanted to the field. Plants were subjected to two N treatments, 0 and 225 kg N ha1, replicated three times in a split-plot design. Plant parts were collected separately 111 days after transplanting, dried, weighed, and analyzed for N concentration. Nitrogen rate and potato species had significant effects on total dry weight, N content, and tissue N concentration. The regression coefficient of N concentration on total dry weight was very low (r=0.22, NS), whereas the regression coefficient of total N content on total dry weight was high (r=0.94, P>0.001). At both low and high N environments, Russet Burbank had greater dry weight than all the accessions. Several wild accessions, especiallyS. chacoense, S. commersonii, S. kurtzianum, S. microdontum, andS.phureja, had equal to or greater dry weights than Russet Norkotah or Red Norland. For N uptake efficiency, 2,7, and 20 accessions were ranked better than Russet Burbank, Russet Norkotah, and Red Norland, respectively. Recovery of soil applied N by the varieties ranged from 16 to 36%; the top seven wild accessions recovered between 27 and 49%. Based on plant growth without added N fertilizer and relative response to N fertilizer, the species were categorized into four relative N use efficiency groups: good foragers with good response to N, poor foragers with good response to N, good foragers with poor response to N, and poor foragers with poor response to N.ResumenEl germoplasma exótica de la papa podría contener caracteres útiles para mejorar la eficiencia del uso del nitrógeno en papas cultivadas(Solanum tuberosum L.). El objetivo de este estudio fue evaluar una “muestra” de la coleccion del germoplasma silvestre para analizar la produccion de biomasa, absorción de nitrógeno y eficiencia del uso del N. Durante la estación de crecimiento de 1993 se llevó a cabo un estudio de campo en un suelo franco-arenoso en Becker, Minnesota. Plantulas uniformes de 39 entradas silvestres y 3 variedades se desarrollaron bajo condiciones de invernadero y, después de 40 días, fueron trasplantadas al campo. Las plantas fueron sometidas a dos tratamientos de N, 0 y 225 kg N ha1, en un diseno de parcela dividida con tres replicaciones. Diferentes partes de las plantas se cosecharon en forma separada 111 días después de haber sido trasplantadas, secadas, pesadas y analizadas por su concentración de N. La tasa de nitrógeno y la especie de papa tuvieron efectos significativos sobre el peso seco total, contenido de N y concentración de N en el tejido. El coeficiente de regresión de la concentración de N sobre el peso seco total fue muy bajo (r=0.22, NS), mientras que el coeficiente de regresión del contenido total de N sobre el peso seco total fue alto (r=0.94, P>0.001). En ambos tratamientos, de bajo y alto contenido de N, Russet Burbank tuvo en mayor peso seco que todas las entradas. Varias entradas silvestres, especialmenteS. chacoense, S. commersonnii, S. kurtzianum, S. microdontum yS. phureja tuvieron un peso seco igual o mayor que Russet Norkotah o Red Norland. En el análisis de la eficiencia de la absorción del N, 2, 7 y 20 entradas fueron clasificadas mejor que Russet Burbank, Russet Norkotah y Red Norland, respectivamente. La recuperación del N aplicado al suelo por las variedades varié de 16% a 36%; las 7 entradas silvestres más altas recuperaron entre 27% y 49%. Basándose en el crecimiento de la planta sin añadir fertilizante de N y la respuesta relativa al fertilizante de N, las especies fueron clasificadas en cuatro grupos relativos para la eficiencia del uso del N: buena producción de follaje con buena respuesta al N, pobre producción de follaje con buena respuesta al N, buena producción de follaje con pobre respuesta al N y pobre producción de follaje con pobre respuesta de N.

Early detection of Verticillium wilt resistance in a potato breeding program

Nine potato clones/cultivars selected for varying degrees of Verticillium wilt (VW) resistance based on degree of vascular colonization, were intercrossed and outcrossed to 13 uncharacterized clones. Based on growth characteristics of 3,535 seedling transplants and an assay quantifyingV. dahliae in potato vascular tissue, 404 clones were selected for further tests. The average number ofVerticillium dahliae colony forming units (CFU) expressed as Log10(CFU + l)/0.1 ml of plant sap for the 404 clones was 2.3, and 1.3 and 3.7 for resistant Reddale and susceptible Kennebec checks, respectively. Thirty-five clones (8.66%) had CFU values equal to or less than Reddale suggesting that VW resistance is a readily transmitted trait.CompendioNueve clones/cvs de papa, seleccionados por sus diversos grados de resistencia a la marchitez porVerticillium (VW) basados en el grado de colonizacion vascular, fueron retrocruzados y entrecruzados (menor parentezco) a 13 clones. Basándose en las características del crecimiento de 3 535 plántulas trasplantadas y en un ensayo cuantificativo deV. dahliae en el tejido vascular de la papa, se seleccionaron 404 clones para pruebas adicionales. El número promedio de unidades formando colonias deVerticillium dahliae (CFU), expresado como Log10(CFU + l)/0.1 cm3 de savia vegetal, para los 404 clones fue 2.3,y 1.3 y 3.7 para los testigos Reddale (resistente) y Kennebec (susceptible), respectivamente. Treinta y cinco clones (8.66%) tuvieron valores de CFU iguales o menores que Reddale sugiriendo que la resistencia a VW es un atributo transmitido rápidamente.

Breeding value of 2n pollen diploid from hybrids and Phureja in 4x-2x crosses in potatoes

Breeding value of 2n pollen from Phureja — haploid Group Tuberosum diploid hybrids (DHs) and Phureja was compared in crosses with tetraploid cultivars. Mean total yield for Phureja — derived (PT) hybrids significantly exceeded that for DH — derived (DHT) hybrids, and did not differ from that for cultivar parents. PT hybrids had the largest range for total yield, with 13% of the population between 4200 and 5750 gm/plant (0.8 and 4.6% for DHT hybrids and cultivars, respectively). Moreover, the tail of the frequency distribution of total yield for PT hybrids extended 920 gm/plant above that for cultivars. Mean marketable yield for PT hybrids significantly exceeded that for DHT hybrids, but was significantly below that for cultivars. However, the tail of the distribution of marketable yields for PT hybrids exceeded that of the cultivars by 820 gm/plant. Significant general combining ability among 2x and 4x parents for total and marketable yield indicates that the potential of specific crosses can be predicted by average performance of parents in test-crosses. Predictability of parental breeding value and exceptional yield potential of hybrids make 4x-2x breeding an attractive alternative to conventional approaches.ResumenEl valor reproductivo de polen 2n, de híbridos provenientes de Phureja —Tuberosum haploides (GHs) y de clones del Gp. Phureja (P), se comparó en cruzamientos con cultivares tetraploides. El rendimiento promedio de los híbridos derivados de Phureja × Tuberosum (PT), excedieron significativamente aquellos derivados de DHs × Tuberosum (DHT); asimismo no difirieron de aquellos cultivares parentales. Los híbridos PT tuvieron el más amplio rango para rendimiento total, con el 13% de la población entre 4200 y 5750 gms/planta (0.8 y 4.6% para híbridos DHT y cultivares, respectivamente). Del mismo modo, la cola de la distribución de frecuencias de rendimiento total para los híbridos PT se extendió 920 sobre aquellos de los cultivares. El rendimiento promedio comercializable para híbridos PT superaron significativamente a aquellos para hibridos DHT; pero fue significativamente inferior que para los cultivares. Sin embargo, la cola de distribución de rendimiento comercializable para híbridos PT fue superior que aquellos de los cultivares en 820 gms/planta. La habilidad combinatoria general significativa entre padres 2x y 4x para el rendimiento comercializable total indicaron que el potencial de cruzamientos especificos pueden ser predichos en base al comportamiento de los padres en pruebas de cruzamiento. La predicción del valor reproductivo parental y el potencial de rendimiento de los hibridos, hacen del métido de mejoramiento 4x-2x una alternativa atractiva a los métodos comerciales.

Tubers from leaf-bud cuttings: A tool for potato seed certification and breeding programs

The use of leaf-bud cuttings as a tool for rapid clonal increase was studied in 6 cultivars. Small tubers were obtained directly from leaf-bud cuttings maintained for 7 weeks in sand-filled pots or benches. The tubers ranged in size up to 1 1/4 inches (3cm) in diameter. The number of leaf-bud cuttings ranged from 37 to 288, depending on size of mother plant. They averaged 114 cuttings. Almost all of the leaf-bud cuttings produced tubers. The procedure is fast, simple, and provides for rapid increase of selected stocks.ResumenSe estudió el uso de cortes de hoja-yemas en 6 cultivares como una herramienta para el incremento clonal rápido. Se obtuvieron tubérculos directamente de cortes de hoja-yemas mantenidos por 7 semanas en mesas o macetas llenados con arena. Los tubérculos variaron en tamano hasta 11/4 pulgadas (3cm) en diámetro. El número de cortes de hoja-yemas varió entre 37 a 288, dependiendo en el tamaño de la planta madre. El promedio fue 114 cortes. Casi todos los cortes de hoja-yemas produjeron tubérculos. El procedimiento es rápido, simple y sirve para incrementar rápidamente clones selectos.