Abstract:
To get a high economic return of mandarin productivity, some growers tend to expand harvest
period by keeping fruits for longer time on the trees in order to extend marketing season. Hence
this study was carried out during the two seasons (2016 and 2017) to evaluate foliar applications
of some chemicals on-tree storage intervals (fourth harvest periods) of Balady mandarin. Forty
years old of Balady mandarin (Citrus reticulate Blanco) trees budded on sour orange rootstock
(Citrus aurantium, L.Osbeck) planted at 5x5m apart and growing in loam clay soil in a private
orchard located at El Menofia Governorate. The experiment involved eight treatments and its
concentrations carried out at fruit color break as follows 10,20 ppm gibberellic acid; 10,15ppm
2,4- D (2,4-Dichlorophenoxyacetic acid); 2% Calcium nitrate + 0.1% Boric acid ;10 ,20ppm
Cobalt sulfate and control treatment( untreated trees). The obtained results indicated that, all
treatments gave the best results; especially the application of 2, 4-D at 15ppm was the best
treatment for reducing average fruit drop rate (%) and for achieving the highest fruit weight, and
fruit juice weight percentage, TSS / Acid ratio and have thicker fruits peel. Also, GA3 at 20ppm
had superior impact by delaying the over ripe rind color development, increased peel firmness
(peel puncture resistance) and fruit vitamin C content. On the other hand, storage fruits on the
tree till the beginning of March (3rd harvest) was the best period for keeping the fruit quality.
Anatomy study revealed that, cells in the abscission zones were very compact with no
extracellular spaces which are smaller than the neighboring cells. It could be recommended the
possibility of prolonging the storage of Balady mandarins on the tree with maintained fruit
quality until early March, by spraying the trees with 2, 4-D at 15ppm to maximize the
profitability of the grower. Prolonging storage of fruits on trees after this time lead to a decrease
in internal fruit quality under the experiment conditions |
