North American Fruit Explorers mailing list at ibiblio

["Lon J. Rombough" <lonrom@hevanet.com>]

Another factor?  Temperatures around and just after bloom time have an effect.  If it's warm, there is more cell division in the developing fruit, and with more cells, the fruit will be larger when it ripens.  Cold weather at bloom and in the first few weeks means less cell division and fewer cells, hence smaller fruit at ripening.  
-Lon Rombough
Grapes, writing, consulting, my book, The Grape Grower, at http://www.bunchgrapes.com  Winner of the Garden Writers Association "Best Talent in Writing" award for 2003. 
For even more grape lessons, go to  http://www.grapeschool.com
For growing supplies and more;  http://www.grapegrowersolutions.com

On Jul 30, 2007, at 2:39 PM, Lisa Almarode wrote:

Besides thinning fruit, what factors affect fruit size?  nutrients,
grass competition... I know these affect tree size, etc., but I was 
under the impression that fruit size was mostly genetics.

My Wickson plums are quite small (it sets very heavily, thinned to 
1 in 10 but not enough), and friend's Shiro are cherry size; granted 
her tree was planted this spring.  

Lisa in Ashland Oregon