To study the effect of rationalizing irrigation and mepiquat chloride foliar application on
growth, productivity and fruit quality of Florida Brines peach trees grafted on Nimagard root stock and grown in
sandy soil at a private orchard in El- Tahadi road, EL-Behara Governorate, Egypt. A trial in a split plot design
has carried out through two successive seasons of 2018 and 2019. Three drip irrigation levels (100, 80 and 60 %
of ETc) were in the main plot and mepiquat chloride foliar application by three levels (without, 150 and 300
ppm) in sub plot and all trees had fertilized by recommended doses. Results indicated that shoot length (cm) and
number of leaves/ shoot was not significantly affect by the three irrigation levels in both seasons. Reducing
irrigation increased acidity of peach fruits and led to a significant reduction on leaf area (cm)2
, total chlorophyll
contents, yield, fruit weight, flesh weight, seed weight, TSS and total sugars but no significant difference
between irrigation by 80 or 60 % from calculated ETc except with yield and seed weight in both studied
seasons. Number of leaves/ shoot, yield either kg/tree or ton/feddan and fruit flesh thickness (cm) were not
significantly affected by mepiquat chloride foliar application at all concentrations in both seasons. The highest
fruit TSS and the lowest shoot length (cm), leaf length and width (cm), leaf area (cm2
) and total fruit acidity
were obtained from peach trees treated by mepiquat chloride foliar application at 300 ppm but by mepiquat
chloride foliar application at150ppm achieved the highest increase in fruit weight (gr), flesh weight (gr) and fruit
total sugars in both seasons. Additionally, the obtained data from the interaction between irrigation levels and
mepiquat chloride foliar application showed that mepiquat chloride foliar application made the decrease in
irrigation level gave no significantly reduction in shoot length, leaf length and width (cm), leaf area (cm2
)
especially with concentration 150 ppm and with 300 ppm on leaf total chlorophyll contents. However, this
interaction failed to show a clear trend on others studied parameters in both seasons. In addition, peach leaf
anatomy has affected by foliar application with mepiquat chloride at 150 ppm and 300 ppm where a prominent
increase in thickness of lamina of leaf blade more than those of unsprayed ones (control) has found. Finally,
irrigated peach trees by 60% of calculated ETc led to the highest water saving and gave the highest productivity
of irrigation water where every used m3 water gave (4.83 & 5.33 kg peach fruits).