Effect of Bud Load Levels and Summer Pruning on Vine Vigor and Productivity of ''Flame Seedless'' (Vitis vinifera, L.) Grapevines

Abstract

This investigation was carried out through three successive seasons 2016, 2017 and 2018 on 8 years old Flame seedless grapevines (Vitis vinifera, L.) grown in sandy soil under drip irrigation system in Markz-Bader El-Beheira Governorate, Egypt. The vines spaced at 2 x 3m in a raw and between rows, respectively, trained to bilateral cordon with Gable supporting system. The vines were loaded with four bud load levels according to weight of one-year-old wood (pruning) produced in the preceding season. The suggested levels of bud load were control, B20 (weight of pruning as kg. x 20), B30 (weight of pruning as kg x 30) and B40 (weight of pruning as kg. x 40) alone or combined with two cluster thinning (without thinning and thinning to one cluster/ fruitful shoot) and two shoot topping (without topping and shoot topping leaving 20 leaves/ shoot) treatments as summer pruning. The results cleared that, as bud load level decreased from B40 to B20 as bud purest, fertility, vegetative growth parameters as well as cluster and berry physical characteristics improved. The same trend was noticed with thinning and topping treatments. The combination treatment of B30+ cluster thinning+ shoot topping (T15) appeared to be superior to achieve the balance between vine growth and productivity, since internodes length and diameter as well as pruning weight and total biomass were improved. Moreover, T15 recorded the highest yield, enhanced cluster weight, as well as berry physical and chemical quality parameters. This investigation was carried out through three successive seasons 2016, 2017 and 2018 on 8 years old Flame seedless grapevines (Vitis vinifera, L.) grown in sandy soil under drip irrigation system in Markz-Bader El-Beheira Governorate, Egypt. The vines spaced at 2 x 3m in a raw and between rows, respectively, trained to bilateral cordon with Gable supporting system. The vines were loaded with four bud load levels according to weight of one-year-old wood (pruning) produced in the preceding season. The suggested levels of bud load were control, B20 (weight of pruning as kg. x 20), B30 (weight of pruning as kg x 30) and B40 (weight of pruning as kg. x 40) alone or combined with two cluster thinning (without thinning and thinning to one cluster/ fruitful shoot) and two shoot topping (without topping and shoot topping leaving 20 leaves/ shoot) treatments as summer pruning. The results cleared that, as bud load level decreased from B40 to B20 as bud purest, fertility, vegetative growth parameters as well as cluster and berry physical characteristics improved. The same trend was noticed with thinning and topping treatments. The combination treatment of B30+ cluster thinning+ shoot topping (T15) appeared to be superior to achieve the balance between vine growth and productivity, since internodes length and diameter as well as pruning weight and total biomass were improved. Moreover, T15 recorded the highest yield, enhanced cluster weight, as well as berry physical and chemical quality parameters.