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Abstract
Dipping ‘McIntosh’ apples (Malus domestica Borkh.) at harvest in a solution of calcium chloride (4% w/w) and keltrol, a commercial food thickener, (0.3% w/w), slowed the loss of firmness in cold storage. In January, treated apples averaged 0.52 kg firmer and in February, 0.73 kg firmer than the controls. Ca concentration of treated apple flesh was 839 ppm, and of controls 304 ppm. A dip solution of calcium chloride without Keltrol was much less effective in reducing the loss of firmness and in increasing the Ca concn of the flesh.
Abstract
‘Starking Red Delicious’ trees 15 years old on seedling rootstocks were fertilized with 5 levels of N as ammonium nitrate from 0.165 to 3.0 lb. per tree applied in a narrow band from 1961 to 1966 and cultivated at a shallow depth with a rotavator each year in March and May, March alone, or not at all.
Evaluation of fruit quality at harvest time showed that there was no significant effect of N level or cultivation treatments on fruit color. Pressure test was reduced by the higher N treatments but soluble solids concentration was highest at the medium N applications. Titratable acidity was reduced by the higher N treatments but cultivation treatments had no effect. Flesh color of the fruit was the most sensitive of several tests made, higher N and more cultivation causing greener flesh. In tests at the end of storage life, pressure test and titratable acidity were still reduced by the higher N treatments. There was little effect on soluble solids, per cent rots or storage scald. Again, cultivation treatments had no effect.
There was very little difference in yield among the N treatments except at the lowest levels of 0.5 and 0.165 lb. This effect was most marked with no cultivation. The N content of the leaves was increased by the N treatments from approximately 2.1% at the lowest level to approximately 2.4% at the highest level. There was no effect on terminal length or trunk circumference.
It was shown that grass sod with or without moderate cultivation could largely override the effect of a very wide range of N levels. There was a deleterious effect only at very low N levels combined with no cultivation.
Abstract
Apple trees, Malus domestica Bork., cv. Spartan, were grown in pots of quartz sand supplied with nutrient solutions and treated with 8, 4, 2 or 1 meq/1 Ca with all other nutrients constant. Fruit was stored and analyzed for 3 years. Twenty-five percent of the fruits from the 1 meq/1 Ca treatment developed senescent breadown of the flesh after storage but only 1% were affected from the 8 meq/1 Ca treatment. Three-year average Ca concentration in the fruit ranged from 131 ppm in the 1 meq/1 Ca treatment to 178 in the 8 meq/1 Ca treatment. Incidence of breakdown increased through the storage season from October until April when little further increase occurred through June. Magnesium and K concn in the fruit increased with decreasing Ca supply in the nutrient solution.
Abstract
Softening of ‘McIntosh’ apples (Malus domestica Borkh.) during storage was reduced by dipping fruit 2 days after harvest in 4% CaCl2 solution (40 g of commercial CaCl2 in 1 liter of water). The addition of Keltrol, a commercial food thickener, at 3 g/liter to retain more Ca solution on the fruit increased the effectiveness of the treatment. After 4 months storage at 0°C, fruit treated with CaCl2 and with CaCl2 plus Keltrol was 0.30 and 0.56 kg firmer by the pressure test than untreated fruit.
Abstract
Normal fruits of ‘Anjou’ pear and fruits with cork spot (pit) symptoms collected at harvest time from trees of various ages, were peeled, cored, and halved and the calyx ends analyzed for mineral nutrient concentration. Pitted fruits were significantly lower in Ca concentration, but there were no differences in Mg, K, Zn, Fe, Mn or Cu. Pitted fruits had a mean of 219 ppm Ca (dry-weight basis) with a range from 187 to 255 ppm. Normal fruits had a mean of 319 ppm with a range of 244 to 453 ppm.
Abstract
‘Spartan’ apples were dipped in 4% CaCl2 solution after harvest. One week after treatment, the Ca concentration was 19 ppm higher at the 0–2.5 mm depth in the flesh of the dipped fruit. After 2 weeks, Ca was 41 ppm higher at the 0–2.5 mm depth and 26 ppm higher at the 2.5–5.0 mm depth. After 4 weeks, Ca was 36 ppm higher at the 2.5–5.0 mm depth, 25 ppm higher at the 2.5–5.0 mm depth and 16 ppm higher at the 5.0–7.5 mm depth. After 8 weeks, Ca was 68, 49, 43, 36, 30, 24, 27 and 27 ppm higher at 8 successive 2.5 mm depths. After 32 weeks, Ca was 84, 70, 62, 62, 61, 58, 62 and 62 ppm higher at the 8 successive depths in the dipped fruit.
Abstract
Fruits of ‘Spartan’ apple were dipped in solutions of commercial CaCl2 after harvest to increase their Ca concentration. Fruits were stored until the following June, then the flesh was analyzed for Ca. Undipped fruit contained 203 ppm Ca and fruit dipped in 4% CaCl2 (wt/vol) contained 278 ppm Ca, dry weight basis. When surfactants were added to the CaCl2 solution, the Ca concentration in dipped fruit was 230 to 250 ppm. When thickeners and surfactants were added, the Ca concentration in dipped fruit was 373 to 825 ppm. These results indicate that surfactants reduce the uptake of Ca by fruit from dips but thickners with surfactants increase it
Abstract
The concentration of Ca in the flesh was closely related to the amount of breakdown in individual apples in 5 lots of ‘Spartan’ apple (Malus sylvestris Mill.) collected over 2 years. Correlation coefficients of 0.9 were obtained using log Ca and linear breakdown or log Ca and log breakdown. The amount of breakdown calculated for the 5 lots by the 2 equations was 100 percent at 70 ppm Ca, from 46 to 100 percent at 100 ppm Ca, from 3 to 12 percent at 150 ppm Ca and less than 2 percent at 200 ppm.
Abstract
‘Spartan’ apples from 29 orchards were dipped in 4% calcium chloride Solution at harvest Senescent breakdown was reduced from an average of 8.3% in the undipped fruit to 2.7% in the dipped fruit Firmness was increased by 0.38 kg (0.84 lb.) and Ca concentration in the fruit flesh by 76 ppm by the dip.