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  • Author or Editor: Max W. Williams x
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Abstract

Weed control with certain triazole or triazine herbicides on 4-year-old nonbearing pear trees (Pyrus communis L. cv. d’Anjou) resulted in markedly increased vigor, as evidenced by higher leaf N, larger trunk circumference, and greater subsequent yields of larger fruit than on trees where weed control was delayed until trees were 6 years old. Fruit from the latter treatment matured earlier and had more yellowness, softer flesh, higher soluble solids, and greater ethylene production than fruit from the vigorous trees. There was also evidence of increased N efficiency with the heterocyclic nitrogen herbicides.

Open Access

Effects of hydrogen cyanamide and Wilthin on blossom thinning and the consequences of thinning on fruit set, yield and fruit quality of `Rome Beauty' was studied. A full bloom application of hydrogen cyanamide at the rate of 0.25% (Dormex formulation) or 0.25% of Wilthin both followed by a fruit thinning by Sevin + NAA effectively thinned mature trees of `Rome Beauty' and had a similar effect on fruit set, yield and fruit quality. The effects of these two chemicals at these rates on several aspects of fruit set, yield and quality were similar to the effects of Elgetol. Hydrogen cyanamide, Elgetol and 0.25% Wilthin at full bloom resulted in a higher percentage of single fruit set, thus, less labor for hand thinning. Application of 0.37% Wilthin at 20% bloom or at full bloom resulted in larger fruit size, but induced fruit russetting. Soluble solids of fruit from trees with Elgetol, 0.37% Wilthin at 20% bloom or at full bloom were higher than fruit from other treatments. Hydrogen cyanamide at 0.50% resulted in a satisfactory level of blossom thinning in `Friar' plums.

Free access

Abstract

Fruit growth measurements in several orchards, from 1959 to 1968 have been used to prepare a table for predicting final harvest size of ‘Bartlett’ pears. At 60 days from full bloom, final fruit diameter to within ⅛ inch can be accurately predicted 83% of the time. The nearer to harvest the sample is taken, the more accurate the harvest size prediction. Temperatures above 80° and below 55°F appear to reduce pear fruit growth.

Open Access

Abstract

Sweet cherries (Prunus avium L.) treated with (2-chloroethyl)phosphonic acid (ethephon) to facilitate harvesting, were low in soluble solids in 1972, but not in 1973. Bruising, pitting and torn stem attachments were attributable to picking method rather than ethephon treatment.

Open Access

Abstract

The levels of auxin, gibberellin, and cytokinin were measured using bioassay methods in pruned and unpruned apple trees (Malus domestica Borkh. cv. McIntosh). Vigorous shoot growth following heavy dormant pruning was accompanied by an increase in cytokinin concentration in the tissues in the early spring. As cell division and cell expansion progressed, the levels of auxin and gibberellin increased. The gibberellin activity in samples from pruned trees was 3 times higher than in samples from unpruned trees. Pruning diminished the midsummer level of cytokinins in the annual shoots.

Open Access

Abstract

Summer pruning, dormant pruning, and growth-regulator treatments were applied for 5 years on newly planted ‘McIntosh’ and ‘Melba’ apple trees (Malus domestica Borkh.) on Alnarp 2 and Mailing 26 rootstocks. All forms of pruning reduced tree growth and yield. Light-to-moderate pruning was the best treatment for forming tree canopies. The reported stimulative effect of summer pruning on flower bud formation was not supported by this research. Pinching shoot tips led to a new secondary growth and inhibited rather than stimulated flower bud formation.

Open Access