Promalin (a commercial formulation of N-(phenylmethy1)-1 H-purin-6-amine plus gibberellins A4 + A7) applied at bud swell and bud burst increased the number of spurs and lateral shoots on one-year-old wood of primary scaffold limbs of young cherry trees. Painted applications gave more consistent responses than sprayed applications. Total length of shoot growth on treated three-yearold cherry trees was more than double that of control trees and lateral shoots induced by Promalin had broad crotch angles.

Foliar sprays of the growth retardant succinic acid-2,2-dimethyl hydrazide (Alar) applied early in the spring on young non-bearing Delicious, Granny Smith, and Gravenstein apple trees reduced the extension growth and increased the amount of bloom in the following spring. Scoring (a knife cut completely around the trunk) in late October and during November on Granny Smith, and Gravenstein trees increased the amount of bloom in the following year. When scoring has performed in early December the response to flowering on Gravenstein variety was greatly reduced. Scoring reduced the extension growth on Granny Smith but not on Gravenstein variety. The use of either Alar or scoring offer practical ways of promoting earlier flowering and cropping of young non-bearing apple trees.

Applications of N-dimethyl amino succinamic acid to the foliage on six-year-old Gravenstein apples restricted the extension growth. The reduced growth was characterized by shorter internode length giving the trees a more compact appearance. The number of leaves was also reduced although not to the same extent as extension growth. The leaf size was not affected. Two successive applications of 1,000 p.p.m. or a single spray of 2,000 p.p.m. applied early in the growing season resulted in highly significant increase of bloom in the following year. Yields were doubled by both treatments.

Results of two experiments and nine orchard trials over three seasons at eight fruit growing districts have shown that fruit shape of Richared, Lalla, Starking, Hi-Early and Common Delicious apples can be improved by applications of the commercial formulation of N-(phenylmethylkl H-purin-61 - 1 amine plus gibberellins A, + A, (Promalin). Promalin at 25 ppm significantiy increased both fruit length: diameter ratio and prominence of calyx lobes. These fruit were considered to have a more characteristic shape and thus said to be more 'typey'. Response varied between strains, and applications during early stages of flowering were more effective than applications after full bloom. The spraying of Promalin with a hand gun caused heavy overthinning and retention of many small fruit on the tree. Applications with air blast spray equipment at spray volumes of 750-1 100 I/ha gave good results. Some air blast applications induced mild fruit thinning, and in several cases seed number was reduced and stem length increased.

In a series of experiments the growth regulator 2-chloroethylphosphonic acid (ethephon) at concentrations from 50 ppm to 400 ppm was applied at various stages during and after flowering to apple cultivars Golden Delicious, Gravenstein, Jonathan, Richared and Starkrimson. On the heavy setting Golden Delicious, Gravenstein and Jonathan cultivars, adequate thinning and satisfactory fruit size was obtained when ethephon at 100 ppm was applied at or shortly after full bloom, followed by naphthalene acetic acid. On the lighter setting Richared and Starkrimson cultivars, one ethephon spray at 100 ppm applied at or shortly after full bloom resulted in adequate thinning. All fruit were eliminated on Jonathan, Richared and Gravenstein cultivars when ethephon was applied at 400 ppm, 300 ppm and 200 ppm, 36, 35 and 42 days after full bloom, respectively.