Interactive effects of nitrogen and phosphorus on verticillium wilt of Russet Burbank potato

A three-year field study was conducted during 1984–1986 to determine the interactive effects of nitrogen and phosphorus fertilization on Verticillium wilt, and yield and quality of continuously-cropped Russet Burbank potato. The experiment was conducted on a calcareous, silt loam soil with low initial levels of NO₃-N (0.9 mg/kg), P (3.5 mg/kg), andVerticillium dahliae (9 cfu/g of soil). The experimental design consisted of a factorial combination of three N treatments (unfertilized check, preplant N or split N) and three P treatments (0,120, or 240 kg P/ha) applied to the same plots during the three-year study. Nitrogen was applied at 0 or 300 kg N/ha in 1984 and 0 or 240 kg N/ha in 1985 and 1986. By the spring of 1986, soil P concentrations for the 0,120, and 240 kg P/ha treatments had increased to 7, 25, and 50 mg/kg and no additional P was applied. In addition to suppressing Verticillium wilt by as much as 95%, N & P treatments also reduced the rate of increase of soilborne inoculum ofV. dahliae. After one season of cropping, the N treatment providing the most efficient N fertilization (300 kg N/ha, split-application) resulted in significantly (p=0.01) lowerV. dahliae counts in soil than the other N treatments. After two seasons of continuous cropping, applying 120 to 240 kg P/ha produced lower populations ofV. dahliae in soil compared to the treatment with no added P. Generally, as N and P treatments approached the highest levels, both wilt incidence andV. dahliae colonization values were reduced. There was a progressive reduction in total yield in nearly all treatments during each year of continuous cropping. Reduction of yield and increased Verticillium wilt incidence was generally greater with N or P deficient plants than with optimally fertilized plants. The highest total and U.S. No. 1 yields and least Verticillium wilt were obtained each year by applying split N and 240 kg P/ha. Results show that optimal N and P can minimize both Verticillium wilt and yield losses that normally occur with intensive potato cropping.     

Influence of seed placement on Russet Burbank potato yield and grade

Potato seed pieces were hand planted with different spacings in the row and percentages of doubles to determine the effects on total yield and tuber size distribution. The objective was to determine acceptable performance levels for commercial potato planters. Average tuber size increased as the percentage of double seed pieces decreased or as the in-row spacing between single seed pieces increased. Yield of tubers smaller than 113 g was the most sensitive parameter and they increased as in-row spacing decreased and as the percentage of double seed pieces increased. Yield of tubers larger than 283 g increased as in-row spacing increased but only for the first year. Total yield was not affected by the change of in-row spacing or the percentage of doubles.     

Relationships of defined PVX infection levels to verticillium wilt,yield, and quality of the Russet Burbank potato

Field studies were conducted over a three-year period to investigate effects of potato virus X (PVX) on the Russet Burbank potato cultivar. Seed (PVX-free and PVX-infected) used for this three-year study originated from the same PVX-free source and was grown and stored under similar conditions. PVX-free seed was found to increase yield over PVX-infected plots by 9 to 32%. With these yield benefits, effects of PVX on either the incidence of verticillium wilt or plant nutrition were not significant. There was a trend (P = 0.10) for a reduction of mean tuber weight when the PVX infection level exceeded 19%. Because of increases of undersized potatoes, the yields of U.S. #1 potatoes were reduced as levels of PVX infection were increased. With a PVX infection level of 36%, the yield of U.S. #1 tubers was reduced by 21% when compared with plots having 0% PVX. At an 88% infection level, the yield of U.S. #l’s was reduced still further (36% lower than plots with 0% PVX). Results demonstrate the importance of the level of PVX infection to potato production.     

The economics of Russet Burbank seed size and spacing

This study is an economic analysis of Russet Burbank seed size and spacing data. Using a representative processor contract, regression analysis was used to estimate the statistical relationship between seed size and spacing and total yield, yield of U.S. No. 1’s, yield of U.S. No. 2’s, yield of 284 gm. and larger tubers, and adjusted grower returns. Depending upon seed cost, the economic optimum seed size ranges from 31 gm. to 48 gm. at 15 cm. spacing. With seed spacing at 23 cm. optimum seed size ranges from 40 gm. to 51 gm. At 31 cm., the optimum size range is 45 gm. to 53 gm. Grower returns adjusted for seed and harvest costs are estimated to be greater at the wider spacing. The results of this analysis have been used to show how grower returns are reduced by variability in seed size and seed spacing. Under normal circumstances, reduced variability in both size and spacing could increase grower returns by $100 per hectare or more.     

Chlorogenic acid content of Russet Burbank potato in Alberta

Samples of Russet Burbank potatoes, collected from the major production areas in Alberta, were analysed for tuber chlorogenic acid content. Chlorogenic acid is known to be associated with the tendency for tuber tissue to darken after cooking. Results indicate a trend for chlorogenic acid content to decrease from Edmonton in the north to Vauxhall in the south. This may be associated with cooler temperatures and higher soil organic matter in the northerly locations     

Cell size in Russet Burbank potato tubers with various levels of nitrogen and soil moisture tensions

Russet Burbank potatoes were grown at levels of added nitrogen of 0, 135, and 270 kg/ha and soil moisture tensions (SMT) of 0.5 and 1.0 atm. With all combinations, there was a consistent gradient of larger to smaller starch-storage parenchyma cells from stem end to bud end of mature tubers. Stem and bud ends of tubers grown at a SMT of 0.5 atm with N had smaller cortical and pith (innermost medullary or water-core) cells than did ends of tubers grown without N. Perimedullary tissues of bud ends of tubers receiving N likewise contained smaller cells than did corresponding tissues of tubers grown without N. No pronounced differences in cell size were found in tissues from the midsections. In bud-end tissue of tubers grown at a SMT of 1.0 atm, there were no consistent differences in cell size with respect to N levels. However, pith, perimedullary, and cortical tissues of the midsections and stem ends of tubers receiving N had smaller cells than did corresponding tissues from tubers without N. The different patterns of cell size in tubers grown at different SMT indicate that the effects of N may be influenced by soil moisure.     

The effect of soil moisture and nitrogen on yield and quality of the Russet Burbank potato

A study was conducted to obtain more information on the effects of soil moisture and nitrogen on yield and quality of the Russet Burbank potato. Total yield of tubers increased with nitrogen rates as a result of more tubers per plant and larger tubers but the percent of malformed tubers also increased. Increased nitrogen rates decreased of dry matter of tubers and increased the total amino-nitrogen content of the tubers. Placing all of the nitrogen in bands on each side of the row produced more tubers having growth cracks, culls and reduced yield of No. 1’s when compared with broadcasting. Applying a moisture stress to potato plants during the early tuber set period increased the percentage of malformed tubers having pointed stem ends, bottlenecks and dumbbell shapes; although total yield and grade of tubers were not significantly affected. Irrigating when available soil moisture was 75 or 85 percent instead of 65 percent during the growing season did not affect total yield, grade or tuber quality at the five percent probability level.     

Petiole analysis and the nitrogen fertilization of Russet Burbank potatoes

The effect of nitrogen rates on the yield of Russet Burbank potatoes was studied in field experiments in Idaho. Petioles were sampled at the 6-to-8 leaf stage and thereafter at two week intervals until mid August. Petiole nitrate concentrations were very high early but decreased rapidly as the season progressed and declined to a very low level as the plants matured. The nitrate content of the petioles reflected the amount of N applied to both locations. Nitrogen applications increased total yield and the quantity of the larger size tubers. A highly significant correlation was found between the early season petiole nitrate concentrations and total yield. Suggested ranges of petiole nitrate concentrations were developed as a guide to efficient N fertilization of Russet Burbank potatoes in Idaho.     

Influences of the Rhizoctonia disease on production of the Russet Burbank potato

Pentachloronitrobenzene (PCNB) treatment (20 lb/A – 22.4 kg/ha) showed significant reduction ofRhizoctonia (Rhizoctonia solani Kühn) symptoms on potato. The PCNB treatment increased the number of non-girdled stolons as compared to untreated plots by 50, 34, and 30% at respective seedpiece spacings of 6, 9, and 12 in (15, 23, and 30 cm). Numbers of non-girdled stolons in PCNB-treated plots at 9- and 12-in spacing did not differ significantly from those in untreated plots at 6-in spacing. Yield differences (either total or U.S. #1) among treatments were not observed, but size differences were evident. Closer spacing or PCNB treatment or both increased the number of small U.S. #1 potatoes and decreased the number of large U.S. #1 potatoes (over 7 oz. - 199 g). Although the number of smaller potatoes was increased by 27% with PCNB treatment, the percentage of malformed tubers was reduced by 50%. Tuber size was reduced as the number of non-girdled stolons was increased (P =.001). Results suggestthat Rhizoctonia control may benefit the fresh potato packer and seedgrower by potentially reducing seed requirement/acre, by increasing capacity for single-drop seed production, and by greater control over U.S. #1 size.     

Seasonal variation of root distribution of irrigated,field-grown Russet Burbank potato

Root density of irrigated, field-grown Russet Burbank potatoes grown on Plainfield loamy sand was determined periodically from soil core samples during the 1973 growing season. Total root length and weight also were measured. Under these growing conditions, the roots essentially were restricted to the plow layer in this soil, decreasing rapidly below this depth. The root density in the plow layer generally ranged from 2 to 6 cm of roots per cm³ of soil, with lower values at greater depths. The root density exceeded 6 cm/cm³ in only a few cores, with a maximum of 11 cm/cm³ obtained on one core in the 10 to 20 cm depth adjacent to the plant. Roots with diameter less than 0.2 mm accounted for about two-thirds of the total root length. A decrease in total root length and dry-weight per plant occurred at the end of the growing season, coincident with the usual decrease in foliage dry weight. The root density beneath the furrow was not significantly different from that within the plant row during most of the growing season.     

Response of Russet Burbank potatoes to soil fumigation and nitrogen fertilizers

Two field studies were conducted to determine the effects of soil fumigation on the response of Russet Burbank potatoes (Solanum tuberosum L.) to NH₄-N or NH₄NO₃ fertilizers. In one study fumigation increased yields but N source had no effect. In the other study fumigation had no effect but NH₄-N provided higher yields than NH₄NO₃. Microbial studies indicated that although populations of nitrifying bacteria were initially altered by fumigation, nitrification rates were similar to those in non-fumigated soil. In a controlled environment study in which potatoes were grown in fumigated field soil, neither N source nor fumigation had any effect on growth or yield. These studies indicated that fumigation had no effect on the response of potatoes to NH₄-N or NH₄NO₃ fertilizers.     

Effects of sulphur dioxide and nitrogen dioxide on shoot and root growth of Kennebec and Russet Burbank potato plants

The effects of sulphur dioxide (SO₂) and nitrogen dioxide (NO₂), singly and in combination, on the shoot and root growth of two potato cultivars sensitive to these pollutant gases were determined using rooted cuttings in controlled conditions. Plants were exposed to 0.11 ppm SO₂ and/or 0.11 ppm NO₂ for 24 hours a day for 7 or 14 days. Kennebec plants had significantly lower root fresh and dry weights after 7 days in the mixture treatments and lower root fresh weight in the NO₂ treatment. Russet Burbank plants were more sensitive to SO₂ and NO₂ than Kennebec. Russet Burbank plants had significantly reduced leaf area, and leaf, stem, and root fresh and dry weights after 7 and 14 days of mixture treatment, and the leaf to root dry weight ratio was higher than in control plants. The combination treatment and SO₂ alone resulted in visible injury on leaves of both cultivars. Changes in tissue water concentration, decreased specific leaf area and decreased root growth suggested that SO₂ and NO₂ altered plant water status and interfered with partitioning of dry matter from the leaves to other plant parts.     

Field performance of transgenic Russet Burbank and Lemhi Russet potatoes

Transformed Russet Burbank and Lemhi Russet clones which contained three different transgene constructs were evaluated for performance under field conditions in Idaho. The transgenic lines were characterized over two growing seasons, using plants grown from both greenhouse produced minitubers (first year) and field grown seed (second year). Individual clones were evaluated for a variety of agronomic and quality properties. Many of the transformed clones showed reduced yield and increases in percent malformed and undersized tubers. Other characteristics, such as specific gravity and fry color, showed less variability. The variation observed in non-transgenic clones regenerated from tissue culture was less than that of the transformed lines. Out of an original population of 57 transgenic lines in tissue culture, maintenance of key agronomic and quality properties of the parental material was observed in only four clones. These results suggest that experiments designed to generate transgenic lines for the marketplace should be initiated with a large number of transgenic clones.     

Soil oxygen and moisture in relation to Russet Burbank potato yield and quality

On a Declo loam, rooting density, final yield and quality of potatoes (Solarium tuberosum cv. Russet Burbank) showed no significant differences among conventional planting, ripping along the row, or forced aeration 30 cm below the top of the row. There were significant relationships between oxygen diffusion rate (ODR) and soil moisture tension (matric potential) at the 30 and 40 cm depths, but these relationships were not significantly different among treatments. In a complementary experiment, sprinkler irrigations at negative soil water matric potentials of 30–40 (wet), 40–50 (intermediate) and 50–60 kPa (dry,i.e., 0.5–0.6 bar tension) produced no differences in total yield. However, the wet treatment gave significantly more knobby and undersized tubers < 113 g (4 oz.) and a lower percentage of U.S. #1 tubers than the intermediate and dry treatments. Premium sized tubers > 284 g (10 oz.) were significantly higher in the dry than in the wet treatment. Fertilizer N was applied periodically during the season and petiole NO₃-N levels indicated adequate levels with no differences among treatments in either experiment. So much attention has been given to the effects of drought and high temperature stress on the quality of Idaho Russet Burbank potatoes, that some growers may now over-irrigate. Results of this research indicate that attention should also be directed to the effects of excess moisture on the size and quality of tubers.     

Spatiotemporally variable area: Mass relationship of Russet Burbank potato leaflets: Implications to potato production models

The relationship between area and mass of fresh Russet Burbank potato leaflets was monitored in two fields throughout two growing seasons in southern Manitoba. A simple ratio was adequate to describe the relationship between leaflet area and mass. The ratio changed non-linearly over the growing season in each field; this time trend differed among fields. During the middle of the growing season, the ratios differed significantly among all trials. In one season, Colorado potato beetles completely defoliated plants in one field; from shortly after plant emergence until no leaves remained, the area:mass ratio in this field was significantly lower than in all other fields. When the area:mass ratio is assumed to be constant or to change linearly over time, estimated leaf area per plant is consistently erroneous. Where models make either assumption, such bias may contribute to site-specificity, or to the inability to accurately simulate the effects of insect attack.     

Dynamic mechanical properties of the Russet Burbank potato as related to temperature and bruise susceptibility

An electro-mechanical vibration exciter and a dropped weight impact device were utilized to determine changes in dynamic mechanical properties of the Russet Burbank potato as influenced by temperature. The vibration exciter was utilized to study the compressive stress-strain relationship for core samples of tuberin the frequency range of 50 to 300 Hz and for temperatures from 35 to 85°F (2 to 30°C) Complex dynamic modulus, storage modulus, and phase angle were found to be independent of temperature but increased with frequency in the interval 50 to 300 Hz. Significant differences in the dynamic mechanical properties of tuber flesh were found according to location along the tuber where the samples were selected. In this study, the complex dynamic modulus was lower for the stem end than for the bud end of the tuber as was the bruise susceptibility Susceptibility of the tubers to bruise damage was evaluated by impacting the tubers with a dropped weight. Depth of bruise was found to be equivalent to length, width, area, or volume of bruise for determining bruise susceptibility. When the velocity of approach of the weight was considered, the ability to predict changes in bruise susceptibility was doubled over that of using temperature alone. This is an improtant finding because it may account for some of the unexplained variations in results of some previous studies where the impact device has been used The response of the Russet Burbank potato to impact was determined by placing a piezoelectric accelerometer in a falling weight. The acceleration-time history of the impact was recorded on a storage oscilloscope. Impact parameters were highly dependent on height of drop. Results of numerical integration of the acceleration-time curves are presented. Peak deformation was found to occur after the point of peak acceleration. Discontinuities in the acceleration-time traces were good indicators of severe damage     

Response of Russet Burbank and Shepody potatoes to nitrogen fertilizer in two cropping systems

Russet Burbank and Shepody potatoes were grown with at-planting N fertilizer rates ranging from 0 to 270 kg ha^?1 during 1986 through 1989. Experiments were conducted each year following small grains and red clover. Total yields and tuber size were strongly increased by N on most sites where potatoes followed small grains. Specific gravities declined with increasing N rate. Total yields of Russet Burbank and Shepody were optimized at an average of 196 and 211 kg ha^?1 of N, respectively, following small grains. The effect of N fertilizer on yields was much less dramatic following red clover. Total yields averaged 88% of maximum with only 45 kg ha^?1 of N applied, compared to 77% of maximum for this N rate following small grains. Total yields for the two varieties were optimized at 126 and 136 kg ha^?1, respectively. U.S. #1 yields were generally not increased at N rates above 45 to 90 kg ha^?1 following red clover and tuber size was not increased at rates above 90 to 135 kg ha^?1. Based on these studies, the N fertilizer credit for red clover grown prior to potatoes can be up to 75 kg ha^?1. Maintenance of tuber quality necessitates conservative use of N fertilizer when potatoes are grown following legumes. The highest N rates tested suppressed total yields of Russet Burbank, a late-season, indeterminate variety, by approximately 9% averaged over cropping systems.     

Freeing Russet Burbank potato plants from ring rot by stem cutting and tuber propagation

Apical stem cuttings removed from potato plants (cv. Russet Burbank) infected withCorynebacterium sepedonicum and expressing mild symptoms of bacterial ring rot were demonstrated to be free from the pathogen. This material remained free of ring rot through two additional stem cutting generations and when grown in the field for four successive tuber generations.