Dale O. Everson

Verticillium wilt of potato: a model of key factors related to disease severity and tuber yield in Southeastern Idaho

In three years (1994, 1995, and 1996), a total of 100 commercial potato fields in southeastern Idaho were surveyed for soil variables, severity of Verticillium wilt, soil inoculum density ofVerticillium dahliae andColletotrichum coccodes, colonization of stems, root, and tubers byV. dahliae andC. coccodes, and tuber yield, size, and quality. As a generalization, factors related to soil integrity (organic matter, organic nitrogen, and increased nutrient availability) were most closely related to wilt suppression and higher tuber yields, whereas factors related to loss of soil integrity (sodium and reduced nutrient availability) were related to increased wilt and lower tuber yields. In a multiple regression analysis, three independent variables, feeder-root infections byV. dahliae, sodium content in soil, and soil organic content, were significant predictors of tuber yield. With these three factors, this model accounted for 49%, 53%, and 62% of the field variability related to total yield in 1994, 1995, and 1996, respectively. Throughout this investigation,V. dahliae root infections had the most direct effect on tuber yield, which emphasizes the importance of quantifying root infections in epidemiological studies of Verticillium wilt. Based on these results, organic matter may be one factor that can be manipulated for suppression of Verticillium wilt without reducing soil populations of the pathogen.

Some Unique Benefits with Sudangrass for Improved U.S. #1 Yields and Size of Russet Burbank Potato

Three studies provided additional knowledge of beneficial effects of sudangrass for yield and quality increases of the Russet Burbank potato. Two of these studies showed significant increases of both U.S. #1 and smooth tubers > 280 g following green manures of sudangrass. These sudangrass (HS-33) effects did not differ from a sorghum-sudan hybrid (Trudan-8). When a sudangrass green manure was compared with a fallow treatment, results of the first study showed mean yield increases of 36% for U.S. #1 tubers > 280 g and yields of a second study by 34% for U.S. #1 tubers. This same sudangrass treatment outperformed green manures of either Austrian winter pea, barley, or sweet corn by increased U.S. #1 yields that ranged from 27% to 61%. By several lines of evidence, these benefits were found to extend beyond the effect of Verticillium suppression. Soil N was significantly increased following green manures of sudangrass, and these increases were in turn negatively correlated with wilt incidence and positively correlated with yields of both U.S. #1 tubers and tubers > 280 g. Additional benefits also included significant increases of tuber grade percentages for marketable tubers and of smooth tubers > 280 g. Benefits from sudangrass green manures beyond the effects of Verticillium suppression became further evident following a greenhouse study that involved field soil and sudangrass that had been grown in the same field. This study corroborated both field experiments by showing increased yields with green manures of sudangrass that approximated 5.5 t ha-1 dry wt. As with the field studies, these yield benefits also extended beyond the effects of Verticillium suppression and were closely associated with significant increases ofFusarium equiseti, F. oxysporum, andF. solani. Throughout all studies, sudangrass green manures significantly increased microbial activities with increased populations ofFusarium spp. and increased concentrations in soil of mineralizable N, organic P, K, Mn, along with the percent soil organic matter -all factors that could have contributed to significant increases of yield and quality.ResumenSe obtuvo información adicional sobre los efectos benéficos del sorgo para el incremento de rendimientos y calidad de papa Russet Burbank por medio de tres estudios. Dos de ellos mostraron un significativo incremento de U.S. #1 y tubérculos uniformes > 280g después de haber recibido sorgo como abono verde. Los efectos del sorgo (HS-33) no mostraron diferencias con el sorgo ...’brido (Tridan-8). Cuando se comparó el abono verde de sorgo con un tratamiento de barbecho, los resultados del primer estudio mostraron un promedio de incremento del rendimiento de 36% para tubérculos U.S. #1 > 280g y los del segundo estudio 34% para tubérculos U.S. #1. El mismo tratamiento de sorgo, superó a los abonos verdes de alverjilla, cebada y maíz dulce con rendimientos de U.S. #1 que variaron entre 27 y 61%. Junto con estas evidencias, los beneficios logrados fueron además un efecto de supresión de Verticillium. El N del suelo se incrementó significativamente después de un abonamiento verde con sorgo y este incremento estuvo negativamente correlacionado con la incidencia de marchitez y positivamente con el rendimiento tanto de U.S. #1 como de tubérculos > 280g. Los beneficios adicionales también incluyen un incremento significativo del porcentaje de tubérculos de grado comerciable y de tubérculos uniformes > 280g. Además de los efectos de supresión de Verticillium, los efectos del abono verde con sorgo se hicieron evidentes después de un estudio de invernadero que incluyó el uso de tierra de chacra y de sorgo que había crecido en el mismo suelo. Este estudio corroboró ambos expérimentes de campo, mostrando un incremento de rendimiento de aproximadamente 5.5 t ha-1 de peso seco con el uso de sorgo como abono verde. Como en el caso de los estudios de campo, estos beneficios en el rendimiento también se extendieron más allá de los efectos de supresión de Verticillium y estuvieron estrechamente asociados con un incremento significativo deFusarium equiseti, F. oxysporum yF. solani. A lo largo de todos los estudios, el uso de sorgo como abono verde incrementó significativamente las actividades microbianas, con un aumento en la población deFusarium spp. e incremento de las concentraciones de N mineralizable, P,K y Mn orgánicos, junto con el porcentaje de materia orgánica en el suelo, factores todos que podrían contribuir a un aumento de rendimiento y calidad.

Endocrine and thermal responses to GnRH treatment and prediction of sperm output and viability in Holstein-Friesian Breeding Bulls

A study was conducted to determine changes in serum LH and testosterone concentrations and in scrotal surface temperature (SST; measured with infrared thermography) following GnRH treatment and to predict the number of spermatozoa collected and the proportion that were viable. Holstein-Friesian breeding bulls (n = 22, average age, 24.3 m.o.; range, 15 to 41 m.o.) were examined twice 30 d apart. Concurrently, semen was collected twice weekly with an artificial vagina. Treatment with GnRH (100 micrograms, i.m.) increased (P < 0.0001) serum LH and testosterone concentrations and increased (P < 0.0001) SST (range 0.6 to 1.1 degrees C; P < 0.05) at the top and bottom of the scrotum. In regression models to predict the total number of spermatozoa, significant independent variables included ultrasonic echotexture of the testes (negative slope), scrotal width (positive slope) and SST at the bottom of the scrotum 45 min after GnRH treatment (positive slope). In regression models to predict the percentage of live spermatozoa, ultrasonic echotexture was a significant independent variable (negative slope). Measurement of testicular ultrasonic echotexture and SST after GnRH treatment augmented measurement of testicular size for predicting the number and percentage of live spermatozoa.

Restricted dietary protein in pregnant beef cows: I. The effect on length of gestation and calfhood mortality☆

Beef cows fed 0.37 Kg crude protein/day during the last four months of pregnancy had significantly shortened gestation (274 days vs. 282 days) and decreased weight gain (25 Kg vs. 66 Kg) compared to control cows fed 0.96 Kg crude protein/day. Calf mortality in the low protein group was associated with either dystocia (3 calves) or prematurity (2 calves). There were no deaths among control calves. It is suggested that protein malnutrition in late pregnancy may be a contributing factor to neonatal mortality among beef calves.

Restricted dietary protein in pregnant beef cows: II. Effect on the immune response.

Cows fed 0.37 Kg crude protein per day for four months before calving showed no decrease in colostral IgG, IgA, or IgM from cows fed a normal ration. Similarly, no difference in serum immunoglobulin concentration was detected in their calves. Cows in the low protein group developed significantly lower (P < 0.01) titers to Salmonella pullorum antigen than did the normal group. The data show significant positive linear regressions of calf agglutination titer to S. pullorum on the dams colostral titers. Serum levels of IgG measured at 24 hours were significantly lower in calves from second-calf heifers than from these of other age groups. The IgA levels of serums from calves from the six-year-old cows were significantly higher than the serum levels of calves from younger dams (P < 0.01).

Delayed-type skin hypersensitivity and in vitro lymphocyte immunostimulation responses of swine following inoculation with Mycobacterium avium cell walls and a mycobacterial immunopotentiating glycolipid.

Miniature swine (n = 5 per group) were inoculated intradermally with mineral oil-in-water emulsions containing either 150 micrograms of mycobacterial immunopotentiating glycolipid P3 (EP3), 150 micrograms of lyophilized Mycobacterium avium (serotype 8) cell walls (E-MaCW), or 150 micrograms P3 and 150 micrograms M. avium cell walls (EP3-MaCW). Swine vaccinated with E-MaCW and EP3-MaCW developed antigen-sensitive lymphocytes detectable with delayed-type hypersensitivity (DTH) skin tests and lymphocyte transformation assays. Swine injected with EP3 were not sensitized. In general EP3-MaCW evoked a more pronounced in vivo DTH tuberculin skin test and in vitro lymphocyte transformation responses than E-MaCW. Time-course studies indicated a more persistent response in swine injected with EP3-MaCW than in those given E-MaCW. Commercial type Yorkshire swine (n = 5) inoculated intradermally with EP3-MaCW developed cell-mediated immune (CMI) responses to avian tuberculin detectable in vivo with delayed-type skin hypersensitivity and in vitro with lymphocyte immunostimulation responses.

Potassium hydroxide for peeling potatoes

Evolutionary operations (EVOP) were used to obtain conditions for optimum peeling of potatoes with KOH. With peeling at temperatures near 93 C, 20.6% KOH with an immersion time of 1 min 40 sec resulted in good peeling. Peeling at temperatures near 68 C required a KOH concentration of 25% and immersion times near 6 min. The higher immersion temperatures and higher KOH concentrations allowed shorter immersion times while obtaining adequate peeling of the potatoes.Potatoes peeled with KOH and NaOH were made into French fries andd mashed potatoes. Taste panels using the triangle difference test could detect no flavor differences between NaOH and KOH peeled potatoes at the 5% significance level.ResumenOperaciones evolucionarias (EVOP) fueron usados para obtener las condiciones para el Óptimo pelado de papas con KOH. El pelado a temperaturas cercanas a 93 C y 20.6% KOH con un tiempo de inmersión de 1 min 40 sec resultó en un buen pelado. El pelado a temperaturas cercanas a 68 C requirió una concentration de KOH de 25% y de un tiempo de inmersión de cerca de 6 minutos. La temperatura mas alta de inmersión y las mas altas concentraciones de KOH permitieron tiempos mas cortos de inmersión manteniéndose un pelado adecuado de las papas. Las papas peladas con KOH y NaOH fueron fritas a la francesca y preparados en puré. Paneles de degustación que usaron la prueba del triángulo diferencial no pudieron detectar diferencias en el sabor entre las papas peladas con NaOH y KOH al nivel de 5% de signification.