Search Results
Abstract
Mechanically harvested fruit of the strawberry (Fragaria × ananassa Duch.) cv. Veeglow destined for processing can be stored at 1°C in bulk bins for 4 to 6 days if room-cooled, and for 6 to 8 days if forced-air cooled promptly after harvest, without appreciable loss due to rot development or of quality of processed product. Yields of puree from fresh fruit mechanically harvested on day 8 of the storage trial were lower than for fruit that had been forced-air cooled and stored at 0° for 8 days. Sulfur dioxide fumigation immediately after cooling reduced losses due to rot and lowered mold counts, particularly when the fruit was room cooled.
Strawberries (Fragaria × ananassa Duch.) cv. Redcoat were stored at several temperatures and for various intervals in controlled atmospheres (CA) containing 0% to 18% CO2 and 15% to 21% 02. Bioyield point forces recorded on the CA-stored fresh fruit indicated that the addition of CO2 to the storage environment enhanced fruit firmness. Fruit kept under 15% CO2 for 18 hours was 48% firmer than untreated samples were initially. Response to increasing CO2 concentrations was linear. There was no response to changing 02 concentrations. Maximum enhancement of firmness was achieved at a fruit temperature of 0C; there was essentially no enhancement at 21C. In some instances, there was a moderate firmness enhancement as time in storage increased. Carbon dioxide acted to reduce the quantity of fruit lost due to rot. Fruit that was soft and bruised after harvest became drier and firmer in a CO2-enriched environment.
Abstract
Multiple linear regression analysis was used to develop commercial harvest prediction dates for peach ‘Earlired’, ‘Redhaven’, and ‘Loring’. Prediction equations were developed using degree day summations and date of full bloom as variables. These equations were adjusted for geographic microclimatic variation and tested in 6 commercial peach orchards over 4 years. Predicted dates and actual first commercial harvest dates differed by 4 days or less for 100%, 96%, and 84% of the predictions for ‘Earlired’, ‘Redhaven’, and ‘Loring’, respectively.
Abstract
‘Bush Blue Lake 283’ beans (Phaseolus vulgaris L.) were grown with 16 fertilizer treatments at 16 commercial sites in Pennsylvania in 1973-74. No treatment gave significantly higher combined yield at one harvest than the NP treatment (28 kg/ha of each). This treatment resulted in increases of 27% in vine weight and 9% in yield while leaf concentration of Ca and Mg were enhanced by 19% and 36% respectively and K concentration was decreased by 17%. Added K which further increased vine weight but not yield, depressed Mg leaf concentration but this was more than compensated for by the NP enhancement. Although added Mg did not affect growth responses, it increased Mg leaf concentration, decreased Mn concentration and tended to decrease P and Ca concentration but did not lower K leaf concentration. When both K and Mg were added, Mg leaf concentration was no higher. Diammonium phosphate had no injurious effects.
Abstract
A 5-year sweet corn nutrition experiment involving 4 lime treatments, 14 fertilizer treatments, and 2 hybrids was conducted on Hagerstown silt loam which had an initial pH of 5.2. Calcitic, calcitic with 3% Mg and dolomitic (12% Mg) limes applied during the 1st and 3rd years at 4.5 MT/ha increased vigor, yield, percentage of marketable ears, leaf N, leaf P and decreased leaf Mn and Zn. Calcitic lime increased leaf Ca and Mg by 21% and 31%, respectively. Dolomitic lime more than doubled leaf Mg but did not affect leaf Ca. Dolomitic lime increased leaf Mg by 55% 60 days after application. The best fertilizer responses were obtained with 56 kg/ha each of N and P banded for ‘Northern Belle’, with 112 kg/ha of N (75% broadcast, 25% banded), and 56 kg/ha P banded for ‘Deep Gold’. These treatments increased yields (by 36% and 60%, respectively, compared to the check), plant height, ear size and weight, and hastened maturity by 5 days. Additions of K or Mg did not improve the response. Height and yield were reduced and maturity was delayed when Ca (NO3)2 rather than NH4 NO3 was used as the N source. Leaf Ca, Mg, and Mn were lower with Ca (NO3)2 than with NH4 NO3 and urea sources, but leaf N, P, Mn, Cu and Zn increased with the urea source. Leaf Ca and Mg were enhanced by NH4 NO3, Ca (NO3)2, and urea, and depressed by KC1.
Abstract
‘Fordhook 242’ lima beans (Phaseolus lunatus L.) were grown in 1973-1974 with 16 fertilizer treatments and 2 plant stands (11 and 16 plants/m) at 0.96 m row width. Soils used were low in P and Mg, medium in K and high in Ca. Banded fertilizer treatments were 28 or 56 kg/ha of N, P, K, and Mg in various combinations, 5 N sources compared at 56-56-0 kg/ha, and 2 commercial fertilizers, 18-46-0 and 8-24-8. With an increase in plant stand from 11 to 16 plants/m of row, vine growth was increased and maturity was delayed but yield of marketable beans was not influenced. Yields were increased an average of 74% by 6 treatments at or close to 56-56-0 kg/ha with and without K when compared to check. N sources, P and K all affected maturity. Urea, (NH4)2SO4, and NH4NO3 resulted in higher yields than Ca(NO3)2 and NaNO3 primarily by hastening maturity. Leaf concentrations of Ca and Mg were enhanced by P and all N sources while leaf K was lowered. Applied K depressed leaf Mg. Thus when both K and Mg were added to NP treatment, Mg leaf concentration was not changed.
Abstract
Highly significant differences in the leaf content of 10 mineral elements occurred between seedling progenies of 7 apple cultivars. Correlations involving all 10 elements occurred between leaf contents of element pairs. A very high correlation between the accumulation of Ca and Mg suggests a common mechanism for the uptake and translocation of these elements. The wide variations between and within progenies indicate the feasibility of selecting rootstocks highly efficient in the uptake of specific nutrients. The proper use as graft components of stocks so selected offers extensive possibilities for the manipulation of the mineral composition of the scion and, thus, the control of nutrient related disorders. Tree-to-tree differences in such disorders in orchards on seedling rootstocks may be accounted for on the basis of differential nutrient uptake.
Sweet pepper (Capsicum annuum L. cv. Keystone Resistant Giant #3) seeds were imbibed (primed) in salt solutions to determine a) what concentrations would inhibit radicle emergence and b) the influence this delay in radicle emergence would have on subsequent germination. Seeds were primed for 17 days at 23C in petri dishes with KNO3, KCl, NaCl, K2SO4, Na2SO4, 1 NaCl: 1 CaCl2 (mol/mol), Ca(NO3)2, CaCl2, Na2HPO4, and K2HPO4 in 10, 25, 50, 100, 200, or 300 mm of the salts. Germination was not inhibited in the 10- to 100-mm salt range, although most 200- and all 300-mm solutions reduced radicle emergence to <5.0%. The time to 50% germination (T50) of these primed seeds in water significantly (P < 0.01) decreased, when compared to unprimed seeds, and a negative correlation (r = – 0.98) was observed between this reduction and the osmotic potential of the solutions. Solutions with the highest osmotic potentials most severely reduced T50 without reducing the final germination percentage. For seeds primed in K2SO4 or Na2SO4 (200 and 300 mm) through 18 days, the reduction in T50 and duration of priming were negatively correlated (r = - 0.99). Seeds soaked in double distilled water and then dried germinated faster than controls, but not as fast as seeds primed in salt solutions. Priming of pepper seeds in this study was dependent on the osmotic potential of the solution, rather than a specific salt, and the duration of treatment.
Summer-grown Hydrangea macrophylla subsp. macrophylla var. macrophylla (Thunb.) were exposed for 1 week to CzH4 at 0,0.5,2.0,5.0,50, or 500 μl·liter-1 in dark storage at 16C for defoliation before cold storage. The number of leaves remaining per shoot for all cultivars decreased with C2H4 concentration, and >5 μl C2H4/liter was effective in defoliating `Kasteln', `Mathilda Gutges', and `Todi' but not `Merritt's Supreme'.
Abstract
Celery (Apium graveolens L. var. dulce DC.) stored at 0°-1°C in 1.5% O2 had better marketable quality than that stored in air after 11 weeks. Marketable celery was improved by using 2.5-7.5% CO in the storage atmosphere, but not by 2-4% CO2. Decay was most severe on celery stored in 21% O2. Botrytis cinerea Pers. and Sclerotinia sclerotiorum (Lib.) de Bary were the most frequent isolates recovered from decayed celery.