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.     

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.     

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.     

Relationships of seed size,spacing, stem numbers to yield of Russet Burbank potatoes

Studies were conducted in 1970 and 1971 to determine the relationships among seed size, spacing, stem numbers and yield of Russet Burbank potatoes. Cut seed sizes of 0.5, 1.0, 1.5, 2.0, 2 oz whole and a treatment consisting of 14% 0.5 oz seed, 62% 1 oz and 24% 1.5 oz seed were used in combination with seed spacings of 6, 9 and 12 inches. As seed became larger the average number of stems per seed piece increased. Percent stand and plant size rating also increased with larger seed. Total yields increased with an increase of seed size. The highest U.S. No. 1 yield was obtained with 2 oz whole seed spaced 6 inches apart with cut seed of the same size yielding slightly less. Within each spacing, the greater stem numbers per plot resulted in higher yields. However, when combinations of seed size and spacings were used to obtain a given stem number per plot, the higher stem numbers did not result in higher yields. A positive correlation coefficient of +0.982 was obtained between weight of seed piece/stem and total yield.     

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 between stem number,tuber set and yield of Russet Burbank potatoes

Five storage temperatures and three planting dates were used to obtain differences in seed performance. As seed storage temperature increased, average stem number per seed piece significantly increased. Stem number also increased with later planting dates. Germination tests, conducted under controlled temperatures, resulted in a curvilinear response with the least stems per seed piece at 10°C. a maximum stem number at 16°C and a slight decline in number at 21°C. The major effect of planting date was manifested through differences in germinating temperatures which resulted in increased stem number with later plantings. Yield of U.S. No. 1 tubers (5cm or 112 gm minimum) declined significantly as stem number increased. In the first planting, the correlation coefficient between stem number per seed piece and yield was r = ?0.95. Increased stem number and declining yield were attributed to advanced physiological age resulting from exposure to higher temperatures in storage and in the field. As stem number increased with planting date, tuber number also increased. The correlation coefficient between stem and tuber number for the first planting date was r = 0.92. The relationship declined significantly on the third planting date to r = 0.46. From these results it was concluded that economic yields are influenced by stem and tuber number which in turn can be manipulated by control of seed storage temperatures and planting dates.     

Comparison of nitrogen and phosphorus requirements between PVX free and regular Russet Burbank potato seed stocks

A Potato Virus X (PVX) free seed stock resulted in higher total yield and U.S. No. 1 potatoes than regular seed stock which carried PVX. Petiole samples from PVX free seed stock were higher in 2% acetic acid extractable PO₄-P than those from regular seed at all rates of fertilizer phosphorus. A high positive correlation was found between petiole phosphate and yield at early tuber set. Increasing rates of nitrogen increased higher total and U.S. No. 1 yields of potatoes, but also slightly decreased specific gravity. The results of this study indicate that phosphorus fertilizer recommendations for growers using Russet Burbank seed low in PVX will necessarily be different from those made for growers planting ordinary seed.     

Comparison of Russet Burbank yield and quality under furrow and sprinkler irrigation

A survey of growers in the Treasure Valley of western Idaho/eastern Oregon indicated that Russet Burbank potato tends to produce better quality tubers under sprinkler irrigation than with furrow irrigation. Irrigation plot studies were carried out over 3 years on 2 sites to determine if these differences were a result of commonly-used management practices or inherent in the irrigation method. With good water management, irrigation method did not affect yields, but sprinkler irrigation produced tubers with slightly better visual quality and much lower incidence of sugar ends. The reasons for better quality with sprinkler-irrigation were projected to include: 1) less water stress since sprinklers can more uniformly apply the small, frequent irrigations that potato requires; 2) better nitrogen management since furrow applications often leach nitrogen from the root zone; and 3) lower soil temperatures due to sprinkler water evaporative cooling.     

Effect of simulated hail damage on yield and quality of Russet Burbank potatoes

The yield and quality response of Russet Burbank potatoes to simulated hail damage was dependent upon the amount of damage and on the growth stage at which the damage occurred. Plots of Russet Burbank potato plants were subjected to 0%, 10%, 25%, 50%, 75%, or 100% defoliation at 3, 5, 7, 9, 11, or 14 weeks after emergence. A motorized flail was used to simulate the complex damage that occurs during a natural hail storm. Early season simulated hail damage, when the plants were mainly vegetative, caused yield losses proportional to the degree of damage. Simulated hail damage during the early phases of tuber growth caused minor yield losses (< 5%) at low defoliation levels but severe losses at the higher levels with proportional loss of tuber quality. Defoliation later in the season resulted in progressively less reduction of both yield and quality. At or near maturity, late season simulated hail damage caused insignificant losses unless the stems were damaged enough to prevent nutrition and carbohydrate translocation into the tubers.     

Impact of early-season water deficits on Russet Burbank plant development,tuber yield and quality

Russet Burbank potatoes grown on Owyhee silt loam were subjected to early-season moisture stress by delaying initiation of furrow irrigation up to seven weeks after planting. A range of water stress treatments from 4 to 7 weeks after planting resulted in reduced plant size, tuber number and total tuber weight per plant 8 1/2 weeks after planting. Early-season water stress resulting from delayed irrigation onset was associated with improved tuber quality at harvest. Plants water stressed before tuber initiation had fewer tubers with dark stem-end fry colors, reduced percentage of US No. 2 potatoes, and increased percentage and size of US No. 1 potatoes. Increasing duration of soil water potential below -60 kPa early in the season was associated with declining total yield in 1985 but not in 1986. To obtain optimum yield and processing quality, the first irrigation should be no sooner than full plant emergence.     

Effect of seed piece population on the yield and processing quality of Russet Burbank potatoes

The effect of seed piece population on tuber yield, size distribution and processing quality of Russet Burbank potatoes grown under nonirrigated conditions in southern Manitoba from 1983 to 1987 was determined. Seed pieces were planted at 21.7, 26.3, 33.3 and 45.5 thousand seed pieces per hectare, and plant emergence generally exceeded 90% of the seed piece population. Marketable tuber (greater than 5 cm in diameter) yields were not affected by seed piece population. As population increased, however, the number of harvested tubers increased and average tuber size decreased, which resulted in a decreased yield of premium tubers (greater than 284 g) and an increased yield of small tubers (less than 5.0 cm in diameter). Specific gravity, the incidence of hollow heart in maingrade (5 cm in diameter to 284 g in weight) and premium tubers, and fry color were not significantly affected by seed piece population. In the one trial tested, sucrose content decreased as population increased, however, this was not reflected in improved fry color after storage.     

Yield and quality of Russet Burbank potato as influenced by interactions ofRhizoctonia,maleic hydrazide,and PCNB

Soil treatment with pentachloronitrobenzene (PCNB) at 22.4 kg/ha a.i. reduced symptoms of theRhizoctonia disease (Rhizoctonia solani Kühn) on potato (Solarium tuberosum L.) and resulted in significant increases in the numbers of stems and stolons. With disease control there was no effect on either total or U.S. #1 yield, but decreases of tuber size were evident and effects were observed on grade. Yield of malformed tubers was reduced by 35%, but this benefit was counteracted by a 41% increase of undersized tubers. Among U. S. 1’s, yield of non-size A’s (113 to 170 g) were increased by 22%, while tubers in optimum size ranges for french fries and bakers (> 284 g) were decreased by 24%. No effect was observed on carton sized tubers (170 to 369 g). Foliar sprays of maleic hydrazide (MH) applied on either of several dates (23 July, 2 Aug., 13 Aug.) at 3.4 kg/ha a.i. reduced total yield by 4.9 to 5.7%, but yields of U.S. #1 potatoes or sizes > 170 g were unaffected. Treatments with MH on either 23 July or 2 Aug. reduced yield of undersized potatoes by 23%. MH treatments did not interact with PCNB treatment to change either total yield or size, but adverse effects on U.S. #1 yields were indicated. MH treatments applied on either 2 Aug. or 13 Aug. reduced U.S. #1 yields among PCNB treated plots by 7 to 10%. MH reduced length/width ratios and, depending on date of application, increased specific gravity. PCNB did not influence tuber shape or specific gravity, but a significant reduction of standard deviations among length/width ratios indicated greater uniformity of shape with treatment.     

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.     

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.     

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.