[ Effect of Boron and Zinc foliar application on the physiological changes and fruit quality of Vitis vinifera L. C.V Al-hilwani and C.V Al-baladi]

This research was conducted through two consecutive seasons 2009 -2010 in Dama village, Al lajat region, Sweida city, on six year old cultivars (Vitisvinifera L. C.V Al-hilwani and C.V Al-Baladi) irrigated and grafted on B41 rootstock. The trail was designed according to the factorial randomized complete block design (FRCB) in order to study the effect of Boron and Zinc foliar application on some physiological changes and grapevine fruits quality. Two concentrations of zinc (Zn1= 50 ppm, Zn2= 75 ppm) and two concentrations of boron (B1= 30 ppm ,B2= 60 ppm) were applied individually and in combination in eight treatments in addition to the control. Results have shown the positive effect of the boron and zinc foliar application in improving the physiological and quality features of the studied grapevine cultivars. However the treatment with Zn at 75 ppm supplemented with boron at 60 ppm surpassed other treatment significantly in a)-increasing the leaf area for both cultivars Al-hilwani and Al-Baladi with means of 249.13 cm2, 224.55 cm2 respectively: b)- increasing dry leaves weight with means of 0.79 g, 0.69 g respectively and c)- improving cluster weight with means of 610 g, 544.17 g respectively. Moreover, the boron and zinc foliar application caused a significant increase in fruit firmness and total soluble solids (TSS) of both Al-hilwani and Al-Baladi cultivars in addition to reducing total acidity (TA) with percentage of 55 %, 49 % respectively Water content (WC) was reduced by foliar application treatments while a significant increase in relative water content (RWC) was shown with percentage of 6 _ 8.2%. Leaf chlorophyll content (a andb) and total chlorophyll increased in both cultivars in treatments contained boron. Hence, the treatment with Zn at 75 ppm supplemented with boron at 60 ppmwhich helped total chlorophyll increase surpassed with percentage of 51.1% and 70.4% in Al-hilwani and Al-Baladi cultivars respectively. An increase in anthcyanin content was shown in Al-hilwani cultivar in treatments which contained boron with percentage of 84.8%. Through the study of the effect of boron and zinc foliar application on the petioles content of nutrients, the nitrogen content of both Al-hilwani and Al-Baladi cultivars increased with percentage of 34.2% and 28.3% respectively. furthermore, the treatment,with Zn at 75 ppm supplemented with boron at 60 ppm,led to an increase in phosphor content that reaches a percentage of 0.43% and 0.4% in both Al-hilwani and Al-Baladi cultivars respectively, while other foliar application treatments had a negative effect on increasing the potassium content in the petioles of the studied cultivars. The concentration of boron increased in the grapevine petioles on which foliar application was applied. Hence, the highest concentration was shown in the treatment, with Zn at 75 ppm supplemented with boron at 60 ppm, with means of 73.97 ppm and 72.5 ppm in Al-hilwani and Al-Baladi cultivars respectively. Moreover, the treatments that contained the second concentration of zinc Zn =75 ppm whether individually or as part of the composition were the most effective factor in increasing the petioles'zinc content.