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FACTORS INFLUENCING THE SHAPE OF APPLES 



Wil 1 iam J . Lord , 



Department of Plant and Soil Sciences "^ 



Shape of apples is an important contribution to attractive- 

 ness. It is known to be influenced by several factors, one of 

 which is distribution of seeds in the fruits. As most growers 

 know, apples with small numbers of seeds are frequently lop-sided 

 with the less fleshy side being the one lacking seeds. Climate 

 also can affect shape. In Massachusetts, J.K. Shaw in 1914 (A 

 study of variation in apples. Massachusetts Agr. Exp. Sta. Bui . 

 149 ). reported on 'rel ationship between shape of Ben Davis and 

 Baldwin apples and the temperature following bloom; the cooler 

 the temperature, the more elongated the apple. He concluded that 

 during the post-bloom period, temperature variations between the 

 6th and 16th day after full bloom fitted the observed variations 

 in shape more closely than during any other period. 



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 . )v 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 fruit 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 "l^ing" 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 



Recently, M.l^. Williams and E.A. Stahly in Washington (Effect 

 of cytokinins and gibberellins on shape of 'Delicious' apple 

 fruitSy, Jour. Amer . Soc. Hort. Sci . 94 (No. 1):17-19), suggested . 

 o f ^■^ that the influence of temperature, crop size, and, 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. Cy toki ni n-treated fruits were longer than 

 normal with prominent, wel 1 -devel oped calyx lobes, whereas those 

 treated with gibberellin were merely longer.*"' 



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