Field trials were initiated during 2004 at a dryland site near Prosper, N.D., to evaluate the effects of simulated drift from glyphosate to `Russet Burbank' and `Red Lasoda' seed potato during the early senescence stage. Glyphosate was applied at rates 1/3, 1/6, 1/12, 1/24, and 1/48 the use rate for spring wheat desiccation on 10 Sept. 2004 with a CO2 pressurized sprayer operated at 280 L/ha and 276 kPa. The amount of a.m.S added to the spray solution was also reduced accordingly. Following harvest, samples from each plot were placed into cold storage until the following March. A subsample from each plot was slowly warmed to initiate sprout formation. Remaining samples were cut into 57-g pieces, dusted with a seed piece treatment, and stored at 18 °C with about 90% RH until planted. Plots consisted of two 3-m rows at 91 cm-row spacing with a border row on each side and three spacer plants between plots. The trial was arranged as a randomized complete block with four replications. Plots were desiccated on 12 and 19 Sept. and harvested 11 Oct. Tubers were hand-graded shortly after harvest. Results indicated that glyphosate at 70 g ae/ha or more inhibited tuber budbreak by 75% or more compared to untreated. In the field, injury was observed as delayed emergence and, in several instances, no plants emerged. Total yield for `Red Lasoda' was 34.8 Mg/ha for the untreated, which was significantly greater than glyphosate treatments of 280, 140, and 70 g ae/ha. `Russet Burbank' total yield was considerably less at 23.5 Mg/ha for the untreated. Both the untreated and glyphosate at 18 g ae/ha had significantly greater total yields compared with glyphosate treatments of 280, 140, and 70 g ae/ha.
Harlene M. Hatterman-Valenti, Collin P. Auwarter, and Paul G. Mayland
Mack A. Wilson and Michael T. Aide
`Norchip' and `Atlantic' potatoes grown at Blodgett and Dielstadt, Missouri on 2 sandy, well drained entisols were evaluated using four row covers. The row covers were spunbonded polyester, insolar slitted, clear slitted polyethylene and VisPore. Row covers increased the mean afternoon soil temperature from 62° to 108°. The mean plant heights were significantly different among treatments for the cultivar `Norchip' but were not different for `Atlantic'. Data for average and total plant heights were significantly different between the bare soil control and all row covers. The grade a marketable weights and numbers in Kg and nos/Ha of `Norchip' and `Atlantic' potatoes had a significant contrast at the 0.01 level of probability with cultivars.
Gerson R. de L. Fortes, Luciana B. Andrade, Janine T.C. Faria, Marisa de F. Oliveira, and Nilvane T.G. Müller
The potato cultivar Cristal recently released by the CPACT/EMBRAPA Breeding Program has high dry matter and low reduce sugars. These are desirable characteristics as industry processing is concerned. Nevertheless, this is a recalcitrant cultivar. The meristem culture is difficult to establish along with a very low multiplication rate. The aim of this work was to improve the multiplication rate for this cultivar. Two-bud microcuttings derived from apical, mid, and basal regions were inoculated in test tubes with 10 ml MS culture media and vitamins as follows; myo-inositol (100 mg·L–1); sucrose (10 g·L–1). No growth regulator was added. All treatments were placed in a growth room in a 16-hour photoperiod; 25 ± 2°C and 2000 lux. One month later, although it was observed that the final growth was more pronounced for basal microcuttings, no difference could be detected for number of shoots and multiplication rate. It was concluded that it makes no difference whatsoever kind of microcutting is used to start the micropropagation process.
Mohamed S. Al-Saikhan, Luke R. Howard, and J. Creighton Miller Jr.
Two varieties of yellow flesh (Granola and Yukon Gold) and two white flesh (Viking and Russet Norkotah) potatoes were grown near Springlake, Texas in the summer of 1992. Varieties were investigated for their antioxidant activity and total phenolic content. Varieties were significantly different in antioxidant activity and total phenolic content (P = 0.0001). Granola had the highest antioxidant activity and Russet Norkotah the highest total phenolic content, while Yukon Gold had the lowest antioxidant activity and total phenolic content. Further study was conducted on tuber parts (distal end, center, and stem end) and among sections within each tuber part. Differences were slight among tuber parts in antioxidant activity, but significant in total phenolic content. Moreover, the differences were slight among the three sections for antioxidant activity and total phenolic content, while the fourth section containing the skin (epidermal tissue) had the highest antioxidant activity and total phenolic content.
Gerson R. de L. Fortes, Rosilene França, and Adriana C. M. Dantas
This work was carried out in the Tissue Culture Laboratory of Embrapa Temperate Climate aiming to maximize the protocol for in vitro culture of potato cv. Baronesa. The treatments consisted of multiplication of microcuttings with one, two, or three buds with/without leaves and originated from different regions of the shoot: apical, middle, or basal. Each treatment was repeated five times with each replication composed of five explants that were inoculated in 250-ml flasks with 40 ml of the medium containing MS salts and vitamins added to: sucrose (30 g·L-1), myo-inositol (100 mg·L-1), agar (6 g·L-1). The pH was adjusted to 5.6 before autoclaving. After inoculation, the flasks remained in a growth room at 25 ± 2 °C, 16-h photoperiod, and 19 μmol·m-2·s-1 light intensity provided by cool-white fluorescents lamps. Observations were done every 5 days. Final evaluation was performed after 30 days. It was observed that basal microcuttings provided longer shoots and that microcuttings with leaves bore the best ones. This kind of explant also favored a higher number of shoots, axilary buds, and better multiplication rate. The presence of leaves in the microcutting is important when basal explants are used once it can improve the number of axillary buds and the rate of multiplication. The higher the number of buds in the microcutting the lower the rate of multiplication. The in vitro multiplication of potato could be improved by using one-leaf bud basal microcutting.
Tyann Blessington*, Anna L. Hale, Douglas C. Scheuring, and J. Creighton Miller Jr.
We have demonstrated that potatoes contain significant levels of antioxidants important to human health; however, since potatoes are not consumed raw, it is important to determine the effects of cooking/processing on these levels. Therefore, the changes in phenolic and carotenoid content and total antioxidant activity in potatoes were investigated using combinations of storage and cooking methods. Fresh and stored tubers (110 days at 4 °C) of 17 potato cultivars, both raw and cooked (microwaved, boiled, baked, fried), were analyzed for antioxidant activity using the DPPH method. In addition, carotenoid levels were determined for each treatment based on the absorbance of the methanol extraction (oxygenated phenolics and carotenoids) at 445 nm and the hexane extraction (non-oxygenated carotenoids) at 450 nm. Total antioxidant activity as well as carotenoid levels were significantly affected by both genotype and cooking method. Across extraction methods, the microwave and fry cooking treatments were generally highest in antioxidant activity, while boiling was the lowest. Oxygenated carotenoids were significantly affected by storage, while the non-oxygenated carotenoids were unaffected.
Lavanya Reddivari and J. Creighton Miller Jr.
Antioxidants have been widely reported to play an important role in disease prevention. In addition to preventing cancer, stroke, heart diseases, and inflammation, they are also involved in immune surveillance. Since the per capita consumption of potatoes in the U.S. is about 137 lb, even moderate levels of antioxidants in this most important vegetable crop probably have an important human health benefit. About 75% to 80% of antioxidant activity in specialty potatoes is due to phenolics and carotenoids. The objectives of this investigation were to evaluate antioxidant activity and total phenolic and carotenoid content of specialty potato selections from the Texas Potato Variety Development Program, and to identify candidate compounds for cancer cell culture investigations. Potato tubers were also used to identify and quantify individual phenolics and carotenoids. Some 320 specialty selections were screened for antioxidant activity (AA), total phenolic content (TP) and carotenoid content (CC) using DPPH (2,2-Diphenyl-1-picrylhydrazyl), FCR (Folin-Ciocalteu Reagent) and colorimetric assays, respectively. After the initial screening, the top 10% were used for analysis of individual phenolics and carotenoids using HPLC. Wide variability for antioxidant activity, phenolic content, and carotenoid content was found among specialty potato selections, providing evidence for genetic control of theses traits. The specialty selection CO112F2-2P/P (purple flesh, purple skin) had the highest AA (832 μg trolox equivalents/g fw), TP (1553 μg chlorogenic acid equivalents/g fw) and CC (590 μg lutein equivalents/100 g fw). Chlorogenic acid (55% to 60%), caffeic acid (≈5%), gallic acid (18% to 20%), and catechin (18% to 20%) were found to be the most prevalent phenolic acids, and lutein and zeaxanthin were the most prominent carotenoids contributing to antioxidant activity. Gallic acid was identified as the candidate compound for use in cancer cell culture investigations.
Mack A. Wilson and Michael Aide
Potatoes (Solantum tuberosum) were grown on a Lilbourn sandy loam entisol in Charleston, Missouri, with varying rates of potassium fertilizer. Four rates of murate of potash (KCl) were used; 0, 196, 392 and 582 Kg-K/HA. Potassium was measured in tuber and soil by atomic absorption spectrophotometry. The amount of soil potassium was apparently high. Although potassium content in the two cultivars of potatoes, `Norchip' and `Atlantis' was slightly higher (2.3-3.7) as compared to another researcher's data (2%). Obviously, the need for potassium fertilizer for vegetable crops is related to the supplying ability of the soil. Tuber yields (Kg/HA) were higher with added rates of potassium fertilizer than the control, and the results were significant. Yields (Kg/HA) of `Atlantis' were significantly higher than `Norchip.'
Gerson R. de L. Fortes, Luciana B. Andrade, Marisa de F. Oliveira, Nilvane T.G. Müller, and Janine T. C. Faria
The potato cultivar Cristal has recently been released by the CPACT/EMBRAPA Breeding Program. Such cultivar was selected for having high dry matter and low sugar content, which makes it desirable for the chip industry. However, this is a recalcitrant cultivar as far as in vitro multiplication is concerned. The aim of this work was to improve the rate of multiplication for this cultivar when it was submitted to different MS salt and sucrose concentrations in the culture media. Two-bud microcuttings were inoculated in test tubes (20 × 150) mm with 10 ml MS media at 3/4-, 1/2-, and full-strength and MS vitamins added to: myo-inositol (100 mg·L–1), agar (7.0 g·L–1) and sucrose as follows: 10, 20 and 30 g·L-1. Each treatment was repeated eight times and each replicate had eight explants. After inoculation the whole material was kept in a growth room at 25 ± 2°C, 16-hr photoperiod and 2000 lux. The evaluation was done 35 days later. It was found and increase in the number of buds as the sucrose concentration in the media decreased. As far as MS salts are concerned no difference in bud number was observed. The rate of multiplication was slightly higher for MS media at full strength and sucrose at low concentration (10 g·L–1). This treatment could be recommended for this cultivar.
Ibis Quintero, Maritza Ojeda, Yolanda Pérez, Judith Zambrano, and Juan Mazano
In tubers `Kennebec' and `Russet' were applied acetylene, carbide and ethylene to promote sprouting, subsequently the tubers were stored at temperatures of 10 and 15 C. The experiment was a completely randomized, factorial design. The evaluations were done weekly. `Kennebec' sprouted from the second week of applied the treatments to 10 and 15 C while `Russet' sprouted only to 15 C. In the fourth evaluations the effect of promoters was not significantly different to the control. `Kennebec' at 10 C showed greater percentage of sprouting and number of sprout/tuber with respect to `Russet', but at 15 C were not detecte significant differences between the cultivars for these parameters. Number of sprout/tuber in `Kennebec' was not affected by the promoters but `Russet' treated with acetylene and carbide at 10 C showed the largest number of sprout/tuber. The greater sprout length was presented by `Kennebec' in both temperatures.