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  • Author or Editor: D. W. Greene x
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In a population of `Delicious' apples (Malus domestica Borkh.) with varying seed number at harvest, fruit size and Ca concentration in fruit increased with seed number. Neither K nor Mg concentration in fruit was related to seed number. In another population of `McIntosh' apples from 50 commercial orchard blocks, the percentage of fruit that developed senescent breakdown, a Ca-deficiency disorder, decreased linearly as seed number per fruit increased. Low seed number is probably a factor contributing to Ca deficiency in apple fruit.

Free access

Abstract

Ethephon [(2-chloroethyl) phosphonic acid] at rates of 100 to 1000 ppm caused fruit abscission of apples (Malus pumila Mill. cv. Cortland and Mutsu) when applied 26 to 44 days after full bloom. Ethephon alone or in combination with SADH (succinic acid 2,2-dimethylhydrazide) caused fruit abscission of ‘Early McIntosh’ when applied 30 days after full bloom. When sprayed shortly after completion of June drop, no abscission occurred. Although no fruit abscission followed the post-June drop treatment, flower bud initiation was increased. SADH appeared to enhance the fruit abscission capabilities of ethephon.

Open Access

Abstract

Annual applications of 2,6-dichlorobenzonitrile (dichlobenil) for 6 consecutive years at recommended rates caused yellowing of apple leaf margins (LMY). LMY appeared in mid-June or later and increased in severity as the season progressed. Severity of LMY was positively associated with individual trees throughout the study. Comparisons between control and dichlobenil-treated trees showed no differences in tree growth and yield, although they were sometimes negatively correlated with LMY severity.

Open Access

Abstract

Red color development of ‘McIntosh’ apples that previously received a mid-July application of succinic acid 2,2-dimethylhydrazide (SADH) and were then treated before harvest with 2-chloroethylphosphonic acid (ethephon) occurred earlier and more extensively than on controls. Fruit receiving 150 or 250 ppm ethephon were less firm within 7 or 8 days than fruit receiving only SADH. The respiratory climacteric was advanced 6 to 10 days by ethephon treatments as low as 25 ppm. Naphthaleneacetic acid (NAA) was less effective than 2,4,5-trichlorophenoxypropionic acid (fenoprop) in preventing preharvest drop, especially at higher ethephon concentrations. Fruit from all treatments kept well in both CA and air storage provided they were in good condition at harvest. Scald developed to a greater extent on stored fruit that had received ethephon than on controls.

Open Access

Several thinning experiments were initiated in 2003 to test the hypothesis that monitoring fruit growth is an appropriate and accurate method to predict final fruit set early enough to apply supplemental thinners if appropriate. A total of eight thinning treatments were applied in Massachusetts and New York. On the day of thinner application 70 to 100 spurs were tagged on 4-8 trees (replications). All fruit within a spur were individually identified and fruit were measured. At 2 to 3 day intervals fruit diameter was measured at a designated point on the fruit. Growth rate of the fastest growing 20 fruit on the untreated trees was used as the criteria to determine growth rate of fruit that would persist to harvest. A fruit on a treated tree was predicted to abscise if growth rate slowed to 50% or less of the growth rate of the 20 fastest growing fruit on untreated trees. Cold weather in 2003 following thinner application slowed the response time to thinners. Thinning treatments were applied to Delicious, Golden Delicious, McIntosh, and Gala at 7-9-mm stage. BA, carbaryl, and combinations of NAA and carbaryl were used. In Massachusetts accuracy of prediction of final fruit set at 7-11 days after application ranged from 87% to 100% with and average of 95% accuracy compared to final observed drop at the end of June drop in July. In Geneva, N.Y., the temperature was so unseasonably cold following application that prediction of final set at 7 to 11 days after application was between 68% and 79% with an average of 74% accuracy. We conclude that prediction of final fruit set following growth rate of individual fruit shows promise as an accurate predictor of final fruit set early enough to apply supplemental thinners if appropriate.

Free access

Mature peach trees were grown in six different-sized vegetation-free areas (VFAs) (0.36 to 13 m2) with and without stage 3 drip irrigation for 6 years. As VFA size increased, so did the trunk cross-sectional area, canopy diameter, total yield/tree, large fruit yield/tree, and pruning weight/tree. The yield efficiency of total fruit and large fruit initially increased with the increasing size of VFAs and then remained stable over the range of VFAs. Applying supplemental irrigation increased yield of large fruit and leaf N percentage in all VFAs. Cold hardiness was not affected by VFA size or irrigation treatment. The smaller VFAs resulted in smaller, equally efficient trees. Sod management was an effective, low-cost approach to controlling peach tree size, and, when combined with irrigated, high-density production, potentially increased productivity.

Free access

Abstract

Preharvest sprays of aminoethoxyvinylglycine (AVG) drastically suppressed internal ethylene concentrations, and delayed or prevented ripening of ‘McIntosh’, ‘Spartan’, and ‘Spencer’ apples (Malus domestica Borkh.) at room temperature (ca. 25°C) after harvest, the magnitude of delay varying with cultivar and with AVG concentration. However, after treated fruit had been stored with untreated fruit at 0°C, little or no difference in ripeness was discernible between treated and untreated samples. Internal ethylene concentrations in treated fruit after storage were much less than in controls but generally exceeded 1 ppm. Infiltration of ripe fruit with AVG severely suppressed ethylene production, but 2 minute dips in AVG solutions had no effect until after prolonged time in storage.

Open Access

Abstract

Residual effects of single applications of 1000 and 2000 ppm succinic acid 2,2-dimethylhydrazide (SADH) in mid-July or mid-August, 1969, were determined. Mid-August treatment of 2000 ppm SADH inhibited June drop, depressed fruit size and increased fruit set; but it did not affect flowering, seed content and viability during June drop, preharvest drop, flesh firmness, or yield in 1970. Flowering and yield were often reduced in 1971 where SADH was applied in 1969. The results suggest that under some circumstances the residual effects of SADH may tend to induce biennial bearing of ‘McIntosh’ apple trees.

Open Access

Abstract

The influence of Mailing (M)26, M9, M27 rootstocks and stempiece/rootstock combinations M9/Malling-Merton (MM)106, M9/MM111, M27/MM106, and M27/MM111 on growth, leaf nutrition, and fruit quality of ‘Empire’ apples (Malus domestica Borkh.) was evaluated. After 8 growing seasons, height and spread of trees on M26, M9/MM106, M9/MM11, M27/MM106, and M27/MM111 were similiar and were greater than those of trees on M9 and M27. Mn concentration in leaves from trees on M27 was higher than that of leaves from trees on other rootstock and stempiece/rootstock combinations. Production of trees on M26, M9/MM106, and M27/MM106 was greater than that on M9/MM111, M9, and M27. When fruitfulness was related to trunk area, trees on the various rootstock and stempiece/rootstock combinations did not differ in production efficiency. Effect of rootstock or stempiece/rootstock on fruit size was inconsistent. Fruit from trees on M27/MM111 entered in to their climacteric later than those from trees on M26 and M 27 for 2 years and from trees on M9 and M9/MM106 for 1 year, but the delay was small. No fruit flesh firmness differences were detectable. Soluble solids content of fruit from trees on M27 was higher than that of fruit on M26, M9/MM111, and M27/MM111. Senescent breakdown was more prevelant in fruit from trees on M26 than on M9, M27, M9/MM111, and M27/MM111.

Open Access