A comparative study between garlic extract and hydrogen cyanamide on flowering, fruit set and productivity of grapes

الملخص EN

This experiment was carried out during 2016 and 2017 seasons on Flame Seedless grapevines grown at El- Khatatba district, in Menofia Governorate, Egypt.

Climate is one of the important factors that control grape production, in warm-winter regions, where the need of intervention of chemical means to break bud rest becomes a dominant factor for maintaining economic production of table grapes.

However, the problem is more acute when farmers want to grow on organic table grapes in the absence of environmentally friendly natural bud break promoters.

This study aimed to evaluate the effect of a garlic extract in comparison to the conventional use of hydrogen cyanamide in promoting bud break and their effects on cluster quality of Flame Seedless grapevines, aiming to invade the markets earlier to maximize the benefits for the producers and to avoid the negative effects of high summer temperature on the vine clusters quality if harvested late.

Moreover, this study is a trail to examine to how extent garlic extract (which contains GA3 like substance) can substitute the declination of chilling hours.

Five treatments of foliar application [tap water (control); hydrogen cyanamide (H2CN2) 3 and 5%, garlic extract (GE) 3 and 5%] were applied to the vines on three times [the first (D1), mid (D2) and the end (D3) of December].

The obtained results revealed that all treatments were very effective in stimulating vegetative growth, bud burst %, yield, physical and chemical characteristics of the fruits.

Generally, D2 was better than the other two times of spraying in all parameters.

Vines that had been sprayed with 5% GE on D2 were the best for early harvest time as compared with the two other times.

In addition, this treatment increased bud burst, leaves number per new shoot, leaf area and chlorophyll content, cluster weight, yield, the average weight and volume of 100 berries, cluster number, cluster length, cluster width, berry length and diameter, total soluble solid, total sugar, while decreased total acidity.

In addition, vines that had been sprayed with 5% GE on D2 gave early blooming (decreasing the time from spraying to blooming).