Annual cropping of fruit trees is very important and to achieve this, flower or fruit thinning is practiced. By reducing the number of fruit on the tree, the remaining fruit will develop to the optimal size of higher quality and return bloom the
Abstract
Limb applications of 5% or 10% alkaryl polyoxyethylene alcohols (X-77 or X- 45) caused flower bud removal when applied to peach trees [Prunus persica (L.) Batsch] with a hand pump sprayer from first pink to 90% bloom. Applications made in late pink or bloom period caused a greater reduction in fruit set than earlier treatments. Applications made at 90% bloom caused some phytotoxicity to the tips of the first small leaves but did not affect the growth of the terminal vegetative primorida or of larger leaves produced on later terminals. Thinning appeared to be commercially acceptable when applied between 30% and 90% bloom. Fruit size at harvest was greater than the unthinned control. Airblast applications of 10% X-77 on the ‘Loring’ cultivar reduced fruit set about 40%.
Partial thinning of peach (Prunus persica L. Batsch) during bloom to 50% of the necessary level by hand, and followed by adjustment hand thinning at 42 days after full bloom (DAFB) was compared to a similar degree of thinning accomplished entirely at 42 DAFB by hand. Partial flower thinning altered the distribution of fruit by diameter, increasing the percentage of large diameter (≥62.0 mm) fruit harvested compared to unthinned trees or trees thinned entirely at 42 DAFB. Although shoot number per limb was not altered by thinning time, the distribution of shoots by length was affected, increasing the percentage of long shoots (≥20.0 cm). Compared to unthinned trees and trees thinned at 42 DAFB, partial flower thinning increased the subsequent development of flower buds per shoot and the number of flower buds per node. Number of flower buds on the proximal five nodes of shoots 15.0-30.0 cm in length was increased, although not on shoots 5.0-7.0 cm in length. Additional trials established that airblast spray application of AMADS was effective in achieving a similar level of thinning as that accomplished by partial flower thinning by hand in previous experiments. The degree of flower removal exhibited a linear response to chemical concentration. Fruit diameter on chemically flower-thinned trees was greater at adjustment thinning time, when compared to trees thinned by hand at 42 DAFB only. Distribution of fruit at harvest indicated a larger percentage of fruit >65.0 mm in trees which received partial flower thinning in comparison to trees thinned at 42 DAFB only. As a result, overall crop value was increased, based on the commercial processing peach price structure at the time of harvest. Chemical name used: 1-aminomethanamide dihydrogen tetraoxosulfate (AMADS)
108 ORAL SESSION 27 (Abstr. 564–571) Thinning–Fruits/Nuts
191 WORKSHOP 23 (Abstr. 1059-1061) Methods and Techniques for Testing Chemicals Used for Thinning Fruit Crops
108 ORAL SESSION 27 (Abstr. 564–571) Thinning–Fruits/Nuts
Bloom and postbloom thinning is essential to managing yield and fruit quality in modern pear production systems. Much of the ‘Bartlett’ pear acreage in the western United States comprises well-established trees planted at low to medium density
84 ORAL SESSION 26 (Abstr. 183-191) Tree Fruits: Thinning/Bloom Delay
84 ORAL SESSION 26 (Abstr. 183-191) Tree Fruits: Thinning/Bloom Delay
determinant of price, because all fruit greater than 55 mm in diameter receive the same price. To improve fruit size, hand thinning is normally done in most peach and nectarine orchards. It is widely recognized that fruit size is largely determined by crop