Abstracts of papers presented at the Forty-First annual meeting     

Jay L. Haddock  Ray D. Jackson  W. O. Harrington  R. L. Olson  W. J. Weston  Mary L. Belote  W. J. Hooker  A. P. Benson  R. W. Hougas  S. J. Poloquin  R. W. Ross  G. V. C. Houghland  Wm. G. Hoyman  D. R. Isleib  N. R. Thompson  T. Miyamoto  E. J. Wheeler  S. T. Dexter  Hugh J. Murphy  Michael Goven  Alvah L. Perry  G. H. Rieman  D. B. Robinson  R. H. Larson  J. G. Walker  R. L. Sawyer  Lawrence A. Schaal  Clark H. Livingston  Ora Smith  W. L. Smith  Vilhelm Umaerus  L. M. Ware  W. A. Johnson  R. E. Webb  E. S. Schultz  Donald A. Young  L. C. Young 《American Journal of Potato Research》1958,35(3):441-449

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Ventilation of chipping potatoes during the conditioning period     

T. Miyamoto  E. J. Wheeler  S. T. Dexter 《American Journal of Potato Research》1958,35(12):778-783

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THE INFLUENCE ON THE FOLLOWING ARABLE CROP OF SHEEP EXCRETA AND FERTILIZER TREATMENTS APPLIED TO A LEY     

J. L. Wheeler 《Grass and Forage Science》1958,13(4):262-269

The differences in soil fertility in a ley as a result of treatments applied for four years in a sheep-grazing trial were measured by growing crops of wheat and kale. The pasture treatments had been: control, dung, urine and dung plus urine, each combined with four levels of fertilizer nitrogen.
Yields of winter wheat harvested in 1956 ranged from 27.1 to 38.6 cwt. per acre. Plots to which faeces had been allowed to return during the pasture phase outyielded (p <0.001) those from which it was withheld. Urine was relatively ineffective except in combination with nitrogen. In the absence of animal returns, nitrogenous fertilizer depressed grain and straw yields. A top-dressing of K applied to the wheat in spring as a sub-treatment had no significant effect. The percentages of N and K in the grain were unaffected by the former pasture treatments, or by the K top-dressing.
A subsidiary small-plot experiment in which the above pasture treatments had been combined with P and K, each at two levels, was cropped with marrow-stem kale. In general, N applied to the pasture increased kale yields except where dung and urine had been withheld. Neither P nor K had a significant effect, except when combined. The leaf/stem ratio of the kale was reduced by applied N and by P (both p <0.05).
The pasture/arable-crop relationship is considered.  相似文献   

Use of visible and near-infrared spectroscopy to predict pork longissimus lean color stability     

King DA  Shackelford SD  Wheeler TL 《Journal of animal science》2011,89(12):4195-4206

This study evaluated the use of visible and near-infrared (VISNIR) spectroscopy to predict lean color stability in pork loin chops. Spectra were collected immediately after and approximately 1 h after rib removal on 1,208 loins. Loins were aged for 14 d before a 2.54-cm chop was placed in simulated retail display. Spectra were collected on aged loins immediately after removal from the vacuum package and on chops 10 min after cutting. Instrumental color measurements [L*, a*, b*, hue angle, chroma, and E (overall color change)] were determined on d 0, 1, 7, 11, and 14 of display. Principal components analysis of display d 0 and 14 values of these traits identified a factor (first principal component; PC1) explaining 67% of the variance that was related to color change. Partial least squares regression was used to develop 3 models to predict PC1 values by using VISNIR spectra collected in the plant, on aged loins, and on chops. Loins with predicted PC1 values less than 0 were classified as having a stable color, whereas values greater than 0 were classified as having a labile lean color. Loins classified as stable by the in-plant model had smaller (P < 0.05) L* values than those classified as labile. Hue angle and ΔE values were less (P < 0.05) and a* and chroma values were greater (P < 0.05) after d 7 of display in loins predicted to have a stable color than in loins predicted to have a labile lean color. Similarly, chops from loins classified as stable using the aged loin model had smaller (P < 0.05) L* values than those from loins classified as labile. Furthermore, loins predicted to be stable had smaller (P < 0.05) hue angle and ΔE values and greater (P < 0.05) a* and chroma values after d 7 of display than did loins predicted to be labile. Results for the chop model were similar to those from the 2 loin models. Chops predicted to have a stable lean color had smaller (P < 0.05) L* values than did those predicted to have a labile lean color. Chops classified as stable had smaller (P < 0.05) hue angle and ΔE values and greater (P < 0.05) a* and chroma values after d 7 of display compared with chops classified as labile. All 3 models effectively segregated chops based on color stability, particularly with regard to redness. Regardless of the model being used, d 14 display values for a*, hue angle, and ΔE in loins classified as stable were similar to the d 7 values of loins classified as labile. Thus, these results suggest that VISNIR spectroscopy would be an effective technology for sorting pork loins with regard to lean color stability.  相似文献   

Predictive markers in calpastatin for tenderness in commercial pig populations     

Nonneman D  Lindholm-Perry AK  Shackelford SD  King DA  Wheeler TL  Rohrer GA  Bierman CD  Schneider JF  Miller RK  Zerby H  Moeller SJ 《Journal of animal science》2011,89(9):2663-2672

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THE EFFECTS OF NITROGEN SOURCE AND CONCENTRATION ON THE GROWTH AND MINERAL COMPOSITION OF PRIVET     

G. V. Subbarao  R. M. Wheeler  G. W. Stutte  L. H. Levine 《Journal of plant nutrition》2013,36(11):1745-1761

Abstract

Sodium (Na) movement between plants and humans is one of the more critical aspects of bioregenerative systems of life support, which NASA is studying for the establishment of long‐term bases on the Lunar or Martian surface. This study was conducted to determine the extent to which Na can replace potassium (K) in red beet (Beta vulgaris L. ssp vulgaris) without adversely affecting metabolic functions such as water relations, photosynthetic rates, and thus growth. Two cultivars, Ruby Queen and Klein Bol, were grown for 42 days at 1200 μmol mol^?1 CO₂ in a growth chamber using a re‐circulating nutrient film technique with 0%, 75%, 95%, and 98% Na substitution for K in a modified half‐strength Hoagland solution. Total biomass of Ruby Queen was greatest at 95% Na substitution and equal at 0% and 98% Na substitution. For Klein Bol, there was a 75% reduction in total biomass at 98% Na substitution. Nearly 95% of the total plant K was replaced with Na at 98% Na substitution in both cultivars. Potassium concentrations in leaves decreased from 120 g kg^?1 dwt in 0% Na substitution to 3.5 g kg^?1 dwt at 98% Na substitution. Leaf chlorophyll concentration, photosynthetic rate, and osmotic potential were not affected in either cultivar by Na substitution for K. Leaf glycinebetaine levels were doubled at 75% Na substitution in Klein Bol, but decreased at higher levels of Na substitution. For Ruby Queen, glycinebetaine levels in leaf increased with the first increase of Na levels and were maintained at the higher Na levels. These results indicate that in some cultivars of red beet, 95% of the normal tissue K can be replaced by Na without a reduction in growth.  相似文献   

Low potassium enhances sodium uptake in red‐beet under moderate saline conditions     

G. V. Subbarao  R. M. Wheeler  G. W. Stutte  L. H. Levine 《Journal of plant nutrition》2013,36(10):1449-1470

Abstract

Due to the discrepancy in metabolic sodium (Na) requirements between plants and animals, cycling of Na between humans and plants is limited and critical to the proper functioning of bio‐regenerative life support systems, being considered for long‐term human habitats in space (e.g., Martian bases). This study was conducted to determine the effects of limited potassium (K) on growth, Na uptake, photosynthesis, ionic partitioning, and water relations of red‐beet (Beta vulgaris L. ssp. vulgaris) under moderate Na‐saline conditions. Two cultivars, Klein Bol, and Ruby Queen were grown for 42 days in a growth chamber using a re‐circulating nutrient film technique where the supplied K levels were 5.0, 1.25, 0.25, and 0.10 mM in a modified half‐strength Hoagland solution salinized with 50 mM NaCl. Reducing K levels from 5.0 to 0.10 mM quadrupled the Na uptake, and lamina Na levels reached ‐20 g kg^?1 dwt. Lamina K levels decreased from ‐60 g kg^?1 dwt at 5.0 mM K to ‐4.0 g kg^?1 dwt at 0.10 mM K. Ruby Queen and Klein Bol responded differently to these changes in Na and K status. Klein Bol showed a linear decline in dry matter production with a decrease in available K, whereas for cv. Ruby Queen, growth was stimulated at 1.25 mM K and relatively insensitive to a further decreases of K down to 0.10 mM. Leaf glycinebetaine levels showed no significant response to the changing K treatments. Leaf relative water content and osmotic potential were significantly higher for both cultivars at low‐K treatments. Leaf chlorophyll levels were significantly decreased at low‐K treatments, but leaf photosynthetic rates showed no significant difference. No substantial changes were observed in the total cation concentration of plant tissues despite major shifts in the relative Na and K uptake at various K levels. Sodium accounted for 90% of the total cation uptake at the low K levels, and thus Na was likely replacing K in osmotic functions without negatively affecting the plant water status, or growth. Our results also suggest that cv. Ruby Queen can tolerate a much higher Na tissue concentration than cv. Klein Bol before there is any growth reduction.  相似文献   

Influence of cultivar resistance toVerticillium SPP. On potato early dying     

T. A. Wheeler  R. C. Rowe  R. M. Riedel  L. V. Madden 《American Journal of Potato Research》1994,71(1):39-57

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Utilization of potatoes for life support systems in space. IV. Effect of CO2 enrichment     

R. M. Wheeler  T. W. Tibbitts 《American Journal of Potato Research》1989,66(1):25-34

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The effect of cultivar on the rate and extent of combining pea straw degradability examined in vitro using the Reading Pressure Technique     

F. L. Mould  G. Hervás  E. Owen  T. R. Wheeler  N. O. Smith  & R. J. Summerfield 《Grass and Forage Science》2001,56(4):374-382

Although about 225 000 t dry matter (DM) pea straw is produced annually in the UK, no recent data exist with respect to its nutritive value when offered to ruminants. This study, to examine field pea crop waste (straw) from 12 commercial cultivars of combining peas, was therefore undertaken when material grown as part of a European field pea network trial at Reading in 1998 was made available. The straw was subjected to chemical analysis and examined in vitro using the Reading Pressure Technique to generate gas production profiles and to determine both rate and extent of DM and organic matter degradation. Ash and crude protein (CP) concentrations (69 and 65 g kg^–1 DM) were generally lower than published values for legume straws but higher, especially CP, than cereal straws. Neutral‐detergent fibre concentrations were slightly lower, and metabolizable energy (ME) values, derived from degradable organic matter assessed in vitro (iOMD), higher than cereal straws, ranging from 6·0 to 8·1 MJ ME kg^–1 DM. Both cumulative gas production and rate of gas release varied significantly between cultivars, as did degradation with 96‐h iOMD values ranging from 468 to 602 g kg^–1. By combining these with the quantity of material harvested, ME yields for the different cultivars were found to range from 15 to 27 GJ ME ha^–1. Considerable, and general highly significant, variation was found between the cultivars examined, which may be used to rank straws with respect to their nutritive value. The cultivars Baccara and Solara followed by Athos and Vital were readily ranked higher than the other cultivars in terms of in vitro fermentation parameters and ME yields. These data suggest that pea straw, although often incorporated into the soil in post‐harvest operations, shows excellent potential as a ruminant forage feedstuff.  相似文献