Effect of vine load and spraying citric acid on fruiting of superior grapevines grown under minia region conditions-Egypt

Abstract EN

During 2014 and 2015 seasons, superior grapevines pruned to leave five vine loads namely 62, 72, 82, 92 and 102 eyes/vine and/ or spraying citric acid at0.0 to 0.4% three times at growth start, just after berry setting and three weeks later.

the target was elucidating the effect of various vine loads and concentrations of citric acid on bud behavior, vine nutritional status, yield and berries quality.

increasing vine loads from 62 to 102 eyes/vine caused a gradual promotion on fruiting buds%, leaf area, pruning wood weight, cane thickness, chlorophylls a& b, total chlorophylls, percentages of n, p, k and mg, berry setting%, yield expressed in weight (kg.) and number of clusters/ vine, cluster compactness, cluster weight and dimensions, t.s.s.%, t.s.s/acid and reducing sugars% .moreover, it caused a gradual reduction on bud burst%, bud fertility%, main shoot length, number of leaves/shoot, wood ripening coefficient, shot berries%, berry weight and dimensions, juice% and titratable acidity%.

all the previous parameters except shot berries% and titratable acidity were gradually enhanced with the increasing concentrations of citric acid.

behavior of buds was unaffected by citric acid treatments.

the best results with regard to yield and berries quality of superior grapevines grown under minia region conditions were obtained by leaving 102 eyes per vine (on the basis of nine fruiting cane X ten eyes plus six renewal spurs X two eyes) during winter pruning plus spraying citric acid at 0.2% three times.