Investigating the effect of cluster number and different level of topping on yield component of grape (Vitis vinifera I.) Cv.Askari.

An experiment was conducted in order to studing on the effects of cluster number and different level of topping on yield components of grapes (Vitis vinifera) cv.Askari during 2004-2005.Experiment was conducted as a randomized complete block design with a 2 factorial arrangement and four replication. The first factor was seven levels of cluster number (0,25,30,35,40,45 and 50 Length,s shoot) and second factor was four level of topping (0,1/3,1/4 and 1/2).The data were analyzed statistically with Mstat-c Software. Combined analysis of variance also was done determine different factors interaction. Results were statistically analyzed using Duncan's multiple range test. The results of analysis variance showed significant difference (pl%) between replications of experiment for all tested characters. Also there was significant difference (pl %) between experiment years for all tested characters. The effect of cluster number factor for many of tested characters such as % Tss , %Ta , Tss/Ta ratio, pH , cluster weight was significants (pl %),except opened bud number and fertility coefficient. Topping effects for many of tested characters such as % Tss, %Ta,Tssffa ratio, pH , was significants (pl%) ,except quantity characters and fertility coefficient.Cluster number x topping and Cluster number x topping x year interaction was no significant (p5%), But cluster number x year interaction for quantity characters and fertility coefficient, and topping x year interaction for cluster weight and yield was significant (pl %). The results of the experiment showed significant difference between cluster number to control from the view point fruit quality treals such as %TSS ,%TA,TssffA ratio and pH , so that the best fruit quality obtained between 25 to 35 cluster number.Also all topping treatments showed significant difference to control from the view point fruit quality treals such as %TSS ,%TA,TssffA ratio and pH but there is no significant difference between topping treatments.Therefore, cluster thining(30 banch per vine) in combination with topping(1/3 topping) for increasing fruit quality of Askari Table grape in a cool-growing¬ season cIimat is recomended.