Effect of Foliar Application with Multi-Micronutrients and Polyamines on Productivity and Storeability of Valencia Oranges

Abstract

The present study was carried out during two successive seasons 2015 and 2016 on of Valencia orange trees (Citrus sinensis L. Osbeck) budded on Volkamer lemon (Citrus volkameriana L.) rootstock, grown in sandy soil under drip irrigation system, in a citrus orchard located in El-Kwamel farm, college of Agriculture, Sohag University, Egypt. The selected trees (33 tree) of Valencia orange cv. were set as a randomized complete block design (RCBD) with 3 replications. The target of this study was to investigate the effect of foliar spraying of multi-micronutrients (1% B, 200 ppm Zn and 250 ppm Fe) and three levels of putruscine (10-3, 10-5 and 10-7mM/Lit) individually or their combinations at full bloom and after ten days from fruit set on productivity and some quality parameters upon harvest as well as during storage at room (ambient) temperature for better marketability of Valencia orange without economical loss. It can be concluded that 10-3mM/Lit (PUT) + Multi-micronutrients treatment gave the highest values of fruit set, retained fruit/tree, fruit weight (g), fruit juice weight (g), fruit juice volume (cm) and fruit peel thickness (mm) of Valencia orange. As well as it gave the highest rate of total soluble solids (TSS) percentage, TSS/acid ratio and ascorbic acid (100g juice) and the lowest values of fruit decay percentage during storage period. This study suggested that 10-3mM/Lit (PUT) + Multi-micronutrients treatment may be consider a useful technology for improve productivity and some quality parameters upon harvest of Valencia orange trees. As well as, the same treatments to avoid the negative quality effects during fruit storage at room (ambient) temperature especially increase the rate of total soluble solids percentage, TSS/acid ratio and ascorbic acid (100g juice) for better marketability of Valencia orange fruits without economical loss.