Improve the yield and quality of red roomy and thompson seedless grape cultivars

الملخص EN

Experiments were carried out at the experimental orchard of Assiut university, faculty of agriculture.

the experiments aimed to overcome the looseness of berries as well as improving the yield and berry quality of red roomy grape cultivar by using boron, zinc and naa.

the study also aimed to reduce the cluster compactness by using ga3 and cluster thinning in order to improve the quality of Thompson seedless grape cultivar.

the treatments significantly increased the initial fruit set (ifs) and decreased the berry drop percentage.

the cluster numbers not significantly affected by various treatments.

however, the treatments increased the yield over the control.

the control vines gave the lowest yield among all the treatments.

the present study showed that there were no significant differences between treatments on the cluster width.

on the other hand, treatments exhibited significant differences comparing with the control in respect of the cluster height.

the treatments except of spraying with naa had significant differences comparing with the control in respect of the cluster weight.

however, the control vines gave the lowest cluster weight during the two studied seasons.

on the contrary, the control gave the highest weight of 100 berries.

on the other hand, although the control produced the highest juice weight of 100 berries but the differences were not significant during the two seasons of study.

there were no significant differences between the treatments in respect of tss% during the two studied seasons.

the sugar contents took the same trend of tss%.

on the other hand, there were no significant differences between the treatments on the cluster number per vine of thompson seedless grape cultivar.

yield weight significantly affected by ga3 application.

the lowest yield obtained from the control.

data revealed that spraying the cluster with ga3 at 5 + 20 + 30 ppm gave the highest values of cluster width (cm) and height (cm).

the clusters treated with ga3 at 5 + 20 + 30 ppm were the heaviest clusters among all the treatments and the differences between their values and the values of other treatments were significant during the two seasons of study.

the weight of 100 berries and 100 berreis juice weight took the same trend of cluster weight.

on the contrary of the previous results, the control and cluster thinning followed by ga3 at 5 ppm + thinning had the highest tss% in the berry juice.

concerning the acidity percentage, the differences between the treatments mostly insignificant.

ga3 application recorded also the least ratio of tss/acid ratio, however, the other treatments significantly surpassed it in this respect.

cluster thinning gave the highest percentage of total sugars followed by ga3 at 5 ppm + thinning and then the control.

this study concluded that the beneficial effects of spraying boron and zinc during flowering to increase the berry set and decrease berry drop of red roomy grape cultivar.

on the other hand; gibberellic acid (ga3) spraying increased berry size, cluster weight and expand the cluster length of thompson seedless grape cultivar that suffering from cluster compactness.

cluster thinning can be used for increasing berry and cluster weight and improving the quality.