769 International Journal of Progressive Sciences and Technologies (IJPSAT) ISSN: 2509-0119. © 2021 International Journals of Sciences and High Technologies http://ijpsat.ijsht‐journals.org Vol. 29 No. 1 October 2021, pp.30-36 Corresponding Author: Fatiha Hakimi 30 Effects of Foliar Calcium Applications on Raspberry Fruit Quality and Shelf Life Fatiha Hakimi *,1 and Hamza Lafrikhi 1 1 Department of Production, Protection and Plant Biotechnology. Agronomy Unit. Hassan II Institute of Agronomy and Veterinary Medicine. Rabat, Morocco. Abstract—The current study investigates the effect of foliar calcium applications on fruit quality of 'Carmina' raspberry. The first product is a liquid fertilizer (CaO: 12%) applied in three doses: T1 (100 cc/hl), T2 (200 cc/hl) and T3 (400 cc/hl). The second product is Calcium Nitrate (CaO: 26.3%) used in a single dose T4 (230.8 g/hl). Data collected included fruit weight and caliber, rating of fruit colour, firmness, acidity, total soluble solids (TSS), and fruit weight loss during storage. Fruit and leaves were sampled to determine Ca concentration. Results show that foliar treatments had no significant effect on fruits average weight, nor their size. Treatments T2 and T3 significantly increased fruit firmness. Fruit TSS and acidity showed no significant differences from T0. Applications did not affect post-harvest fruit weight losses. Foliar application of calcium caused an increase in leaf calcium content of 46 and 42% respectively for T2 and T3, and an increase in fruit calcium content of 35 and 18% respectively for T2 and T3 compared to T0. There was no difference between the contents of leaves and fruits regarding the other elements (Mg, K, Fe, Mn, Zn and Cu). The right frequency of application is once every 8 days. Keywords—Calcium; foliar fertilization; raspberry (Rubus idaeus); fruit firmness; post-harvest quality I. INTRODUCTION In the last decade, the berries sector and in particular raspberries are booming with world production reaching 822,493 tonnes in 2019. Morocco's production in the same period was around 24,500 tons [1]. In recent years, the raspberry tree has become increasingly important because of the possibilities of extending its cultivation in areas with mild winters, such as the countries of the Mediterranean basin. The areas dedicated to raspberries in Morocco went from 30 ha in 2006 to 3,100 ha in 2019-2020 and exports reached 35,400 tonnes in the same campaign [2]. The country has methodically invested in consolidating its reputation in many importing countries as a reliable supplier of high-quality fruits and vegetables. Nowadays, raspberries culture occupies a modest place in three of the most important regions in Morocco, namely Loukkos, Gharb and Souss-Massa. It plays a substantial role in the socio-economic development of these regions as it is considered a highly profitable and employment-generating culture. However, raspberries are very perishable fruits with high respiration rates and a fragile structure. They are easily spoiled by mold and have a very short shelf life of around 3 to 5 days [3]. This is particularly problematic for export, with a considerable loss of firmness and freshness and the rapid development of rots. In general, a nutrient-balanced fertilization is essential to ensure optimal yield and to have good quality fruit [4]. Calcium is one