Population density studies with Russet Burbank I. Yield/stem density models

Two reciprocal polynomial models were used to quantify yield/stem density relationships in the Russet Burbank cultivar y^?θ = α + β? and y^?1 = β₀ + β₁? + β₂?² where y = yield per plant; ? = stems m^?2 and β₀, β₁, β₂ and α, β, and θ are fitted parameters. The use of a systematic design allowed characterisation of the yield/density response surface over a wide range of densities (1.8 to 20.0 plants m^?2) without involving experiments of impractical size. The effect of both seed size (30, 40, 50, 60 gm) and type (cut or whole) on the relationship was studied. Both models provided excellent statistical fits for marketable yield data, while the former model gave a similar fit for total yield data. The form of the relationship was not influenced either by seed size or type. Total yield was asymptotically related to stem density while marketable yield was parabolically related.     

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.     

Comparison of growth and yield parameters of Russet Burbank for a two-year period

The effect of three planting dates on stem, stolon, tuber number and size were compared throughout the 1979 and 1980 growing seasons. A relatively warm April and early May and a relatively cool late May and June in 1980 resulted in significantly higher stem and stolon numbers and a tuber population over double that of 1979. The highest average commercial yields ever recorded in the Columbia Basin were obtained with yields in some fields of 100 tons per ha on 48 hectare irrigation circles. On experimental plots tuber numbers increased from the latter part of May with successive sampling dates until late June and early July when a peak in number was reached after which a significant decline in number occurred. The decrease in tuber number was attributed to the phenomenon of reabsorption which was much greater with later planted potatoes. It occurred only in tubers of approximately 10 g size or smaller. Average tuber size in 1980 was one-half that of 1979 although total yield was 25 tons per ha higher because of significantly larger tuber numbers.     

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.     

Effect of rate and time of fertilization on nitrogen and yield of Russet Burbank potatoes under center pivot irrigation

Applying less N on Russet Burbank potatoes (Solanum tuberosum L.) at planting time may reduce the potential loss of N from sandy soil by wind erosion and leaching early in the season. The objective of this study was to evaluate the effect of rate and time of N fertilization on potato production. Potatoes were grown in outdoor pot cultures with N rates of 75,150 and 300 ppm and in field plots with N rates from 112 to 448 kg N/ha applied in single and split applications. The results from pot cultures harvested after one month’s growth showed that yield of tops increased and tuber yield decreased as applied N at planting increased from 75 ppm to 150 or 300 ppm. Field results showed that the yield of potatoes was as high or higher when N applications were split between planting and when plants were 15 to 20 cm tall (early tuberization) as with the same amount of N applied at planting. Generally 112 kg N/ha at planting time was sufficient when additional N was applied after emergence. Split application of N resulted in more second growth on tubers than when all of the N was applied at planting.     

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.     

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.     

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.     

The influence of physiological age,stem numbers and fertility on yield and grade of Russet Burbank potatoes

The present study was initiated to determine if increased stem numbers produced by physiologically older seed can be compensated for by increased fertilizer rate. Seed tubers held for 2 months at 16 C (physiological older seed) which averaged 3.7 main stems were compared in yield parameters to physiologically younger seed kept at 4 C (average 2.4 stems). The comparison was made at three levels of fertilizer 0, 140, and 280 kg/ha of nitrogen applied in a 16:16:16 (N-P²O⁵-K²O) formulation. Seed size and spacing were equal. Total and U.S. No. 1 yield were significantly higher for the younger seed. The greatest difference was that the younger seed at 140 kg/ha fertilizer yielded significantly more large size (over 280 g size) tubers than the older seed at equal to or double (280 kg/ha) the fertilizer rate indicating that additional fertilizer was not sufficient to overcome the effects of higher stem numbers from older seed. On the other hand, the older seed produced significantly higher yield of the undesirable small sizes.     

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.     

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.     

The effect of irrigation strategies during tuber initiation on marketable yield and development of common scab disease of potato in Russet Burbank in Tasmania

Summary Management of soil moisture deficit during tuber initiation and early development was important for the optimisation of net and marketable tuber yields of cv. Russet Burbank on the typical red ferrosol cropping soils of Northern Tasmania, Australia. An effect of reduced water input during the tuber initiation period on increasing incidence of common scab disease was noted in one trial. In subsequent trials disease inoculum levels were not sufficient to show differences between treatments despite a history of disease at the site. For optimisation of marketable yield and probable assistance in the management of common scab disease it is recommended that irrigation scheduling to known soil moisture deficits be adopted during this period of growth on this soil type.     

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.     

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.