EFFECT OF FOLIAR APPLICATION OF MINERALOR CHELATED CALCIUM AND MAGNESIUM ON THOMPSON SEEDLESS GRAPEVINES GROWN IN A SANDY SOIL B — Fruit quality and keeping quality during storage at room temperature '

This experiment was carried out during the two successive seasons of 2003
and 2004 to study the eflect of foliar application of mineral or chelated calcium and
magnesium on fruit quality and keeping quality during storage at room temperature of
Thompson Seedless grapevines. grown in a sandy soil under drip irrigation system at
El - Sadat region. Menoufeya Govemoratex'Fhe vines were quadrilateral cordon
shaped and trellised by the Spanish Parron system. Ten years old Thompson
Seedless grapevines received three foliar sprays In each season. i. e. at the
beginning of vegetative growth (2"“1I week of March). immediately after fruit set (1"
week of May) and 4 weeks later (1" week of June). The tested foliar spray treatments
included control (water spray). Ca CI; at 0.5%. 1% and 2%. Ca - EDTA at 0.1 %. 0.2%
and 0.3%. Mg 804 at 0.5%. 1% and 2%. Mg - EDTA at 0.1%. 0.2% and 0.3%.
The results indicated that. Mg — EDTA at 0.3% gave the heaviest clusters and
increased number of berries 1 cluster and beny dimensions. Moreover. Mg — EDTA
and Ca - EDTA at 0.3% increased dimensions of cluster. berry weight and size. All
calcium treatments. especially In the chelated form. increased significantly the berry
firmness. adherence strength of berry. decreased berry shattering percentage before
and after storage at room temperature and decreased the decay and loss In fresh
weight percentage estimated 4 days after harvesting at room temperature compared
to the control and Mg applications. The best results of these parameters were
obtained by Ca — EDTA spray at 0.3% followed by Ca — EDTA at 0.2%. T.S.S. (%).
acidity (%) and T.S.S I acid ratio were not aflected by Ca or Mg applications either in
the mineral or in the chelated form. The obtained results suggested spraying calcium
and magnesium in the chelated form at 0.3% on Thompson Seedless rapevines
three times In each season. i. e. at the beginning of vegetative growth (2 week of
March). immediately after fruit set (1" week of May) and 4 weeks later (1" week of
June). to improve the properties of fruit quality and keeping quality during storage at
room temperature.