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In 1963, M.N. Westwood and L.T. Blaney in Oregon (Non-clim- 

 atic factors affecting the shape of apple fruits. Nature 200:802- 

 803.) reported effects of several non-climatic factors on shape 

 of apples. In a study with Red Delicious, rootstocks were found 

 to have a significant effect, with fruits on seedling roots, EM I, 

 or EM XVI being more elongated than those from trees on EM VI, 

 EM VII or EM IX. With Golden Delicious, both crop load and fruit 

 location in the cluster affected the shape of fruits. Those from 

 trees with a light crop (whether the result of heavy thinning or a 

 light bloom) were longer than fruits from trees with a heavy crop. 

 The "king" fruits were longer than side-bloom fruits. 



A possible genetic effect on fruit shape also was studied by 

 Westwood and Blaney using three strains of Red Delicious. They 

 found that fruit shape differed significantly with strain, common 

 Delicious fruits being flatter than Starking and Starkrimson fruits. 



M.W. Williams and E.A. Stahly in Washington (Effect of cyto- 

 kinins and gibberellins on shape of 'Delicious' apple fruits. Jour . 

 Amer. Soc. Hort. Sci . 94(No. 1):17-19), suggested in 1969 that the 

 influences of temperature, crop size, and fruit location in the 

 blossom cluster on fruit shape are possibly related to their ef- 

 fects on growth regulators in the developing fruits. They showed 

 that an application after full bloom of two kinds of growth regu- 

 lators, cytokinins and gibberellins, alone and in combination in- 

 creased fruit length. Cytokinin-treated fruits were longer than 

 normal with prominent, well-developed calyx lobes, whereas those 

 treated with gibberellin were merely longer. To the contrary, it 

 is well known that Alar-85 will cause flattening of apple fruit. 



Recently, C.R. Unrath in North Carolina ( Jour. Amer. Soc. Hort . 

 Sci. 99(No. 4):381-384) reported that for Red Delicious, a single 

 spray of gibberellin (GA 4-7) plus benzyladenine (a cytokinin) ap- 

 plied between full bloom and petal fall appears practical, especially 

 in areas where high post-bloom temperatures normally result in poor- 

 ly shaped fruit. This spray combination improved fruit shape and 

 increased fruit weight. (Unfortunately, gibberellin (GA 4-7) and 

 benzyladenine have no label clearance for use in orchards.) 



■•■This article first appeared in the Jan. -Feb., 1971 issue of Fruit 

 Notes but due to frequent questions pertaining to factors influ- 

 encing shape of apples, this article has been updated. 



2 

 Trade name 



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