Effect of Application Time of Copper Sulfate, Streptomycin and GA3 on Parthenocarpy and Quality of Grapevine (Vitis vinifera L. cv.  Siyah-e-Shiraz')

An investigation was performed in a commercial orchard in Shiraz to study the effect of time of application of CuSO4 and streptomycin on quality and seedlessness of grapevine (Vitis vinifera L. cv. ‘Siyah-e-Shiraz’). The experiment was Conducted as Completely randomized block design with 3 replications. Plants were treated with 25 mgl-1 CuSo4. 5H2o and 200mgl-1 streptomycin 2,4 and 6 days before full blooming. 50 mgl-1 GA3 was applied 10 days after full blooming. Results indicated that both CuSO4 and streptomycin increased parthenocarpy compared with untreated control. Streptomycin and CuSO4 6 days before full blooming plus GA3 produced the highest rate of seedlessness (84%). Both CuSO4 and streptomycin reduced the number of seeds, cluster weight, berry weight, length and diameter of the berries compared with untreated controls. GA3 increased weight of seedless berries, vitamin C and total acid contents unsignificantly.