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30 Oct 2025
By Firstfruits Consulting Website Articles , , , , , , ,

Effect of Potassium, Magnesium, and Calcium Deficiencies on Carbohydrate Pools and Metabolism in Citrus Leaves

Carbohydrate content and related enzyme activities were determined in leaves of rough-lemon (Citrus volkameriana Ten. & Pasq) plants grown under K, Mg, and Ca deficiencies. Starch content was lower and soluble sugar significantly higher in K-deficient than in control leaves. Magnesium- and Ca-deficient leaves, on the other hand, accumulated large amounts of starch. Electron micrographs also showed a reduction in the number and size of starch grains in chloroplasts of K-deficient leaves, while those of Mg- and Ca-deficient leaves were filled with large starch grains.

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30 Oct 2025
Citrus Girdling
0 Comments By Firstfruits Consulting Website Articles ,

Influences of girdling and potassium treatments on fruit quality and some physiological characters of ‘Fremont’ mandarin variety

Growing citrus involves cultural treatments such as girdling and foliar potassium treatment to increase fruit size, yield and quality. The aim of the study was to evaluate the effects of single and double stem girdling, potassium nitrate (KNO3) treatment on leaves and combinations of these treatments on the fruit yield, size and quality characteristics, leaf chlorophyll concentration and leaf nitrogen content, leaf fluorescence (PSII) and leaf sugar content of the ‘Fremont’ mandarin variety. Girdling treatments were applied on the stem by removing 4 mm wide ring of bark at the end of anthesis and after the June fruit drop.

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26 Sep 2025
Citrus Fruit Variety
By Firstfruits Consulting Website Articles , , ,

Citrus fruit quality. Physiological basis and techniques of improvement.

Fruit size can be improved either by increasing carbohydrates availability to fruit or by increasing fruit sink strength. Application of synthetic auxins may act in these two ways, depending on the date of treatment. When they are applied during the physiological drop they have a thinning effect, reducing competition for carbohydrates among developing fruitlets; when applied at the onset of cell enlargement stage fruit sink strength is increased and carbohydrate accumulation in the fruit is enhanced.

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26 Sep 2025
Cross section of fruit
By Firstfruits Consulting Website Articles , , , , , ,

Primary Metabolism in Citrus Fruit as Affected by Its Unique Structure

Citrus is one of the world’s most important fruit crops, contributing essential nutrients, such as vitamin C and minerals, to the human diet. It is characterized by two important traits: first, its major edible part is composed of juice sacs, a unique structure among fruit, and second, relatively high levels of citric acid are accumulated in the vacuole of the juice sac cell. Although the major routes of primary metabolism are generally the same in citrus fruit and other plant systems, the fruit’s unique structural features challenge our understanding of carbon flow into the fruit and its movement through all of its parts.

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29 Aug 2025
Mulch
By Firstfruits Consulting Website Articles , , , , ,

Effect of Various Mulching Materials on Crop Production and Soil Health in Acid Lime

An experiment was conducted to study the effects of mulching on acid lime during 2014-2015 in Randomized Block Design with 9 treatments and 3 replications. The highest increase on plant height (6.63 %), canopy spread in E-W (9.90 %) and N-S (7.60 %) direction was recorded by polythene mulch with black side facing upward (T8 ). The treatment also had a significant influence on yield and yield attributing parameters where T8 recorded the highest number of fruits per plant (163.0), fruit weight (50.22 g) and fruit yield per plant (7.81 kg) while dry grasses mulch (T2) recorded highest number of fruits per branch (7.50) and fruit retention (44.71 %). With respect to quality parameters of fruit, T8 recorded highest total sugar (0.40 %) and reducing sugar (0.61 %) while significant increase on titratable acidity (6.93 %) and ascorbic acid content (33.46 mg/100g) was observed in T2.

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29 Aug 2025
Fertilization
By Firstfruits Consulting Website Articles , , , , ,

Effects of Fertilization Approaches on Plant Development and Fertilizer Use of Citrus

Fertilization is an important part of citrus crop management. However, limited details are available about the fertilization approach on citrus plant development. A pot experiment for the fertilization approaches and fertigation levels were conducted in this study. Four fertilization approaches, namely, drip fertigation (DF), broadcast fertilization (CK+), hole fertilization (HF) and pour fertilization (PF) were tested. The fertigation level treatment included 100% (DF-337.5), 80% (DF-270), 60% (DF-202.5) and 40% (DF-135) fertilizer supply with DF, and the 100% fertilizer supply with broadcast fertilization were served as control (CK). The results showed that DF not only increased the absorptions of nitrogen (N), phosphorus (P) and potassium (K) but also promoted citrus plant height, stem diameter and dry weight.

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29 Jul 2025
Yield
By Firstfruits Consulting Website Articles , ,

Managing Phosphorus for Citrus Yield and Fruit Quality in Developing Orchards

No calibrated phosphorus (P) soil test exists to guide Florida citrus fertilization. Applying P fertilizer to citrus when it is not needed is wasteful and may cause undesirable P enrichment of adjacent surface water. The objective of this study was to establish guidelines for P management in developing Florida grapefruit (Citrus paradisi Macf.) and orange (Citrus sinensis L. Osb.) orchards by determining the effect of P fertilizer rate on soil test P and subsequently calibrating a P soil test for citrus yield and fresh fruit quality. Two orchards were planted on sandy soil with 3 mg•kg–1 (very low) Mehlich 1 soil test P. In Years 1 through 3, P fertilization increased soil test P up to 102 mg•kg–1 (very high).

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29 Jul 2025
Foliar Fertiliser
By Firstfruits Consulting Website Articles , , , , , , , ,

Efficacy of Foliar Urea as an N Source in Sustainable Citrus Production Systems

Foliar fertilisation was reported to be an efficient way to supply nitrogen to fruit trees and to reduce nitrogen losses to groundwater systems and risks of soil pollution and salinity. In this study we report on: 1) the effect of pH of a 1% urea solution applied prebloom and the effect of a multiple foliar-urea spray at the rate of 1% to supply 46 g N/tree to mature ‘Cadoux’ clementine mandarin trees (Citrus reticulata Blanco) on leaf N and its changes during 30 days following application; 2) the resulting effect on yield and fruit size; 3) a comparison made between effects of prebloom foliar application of urea at 0.8% or 1.6% (supplying 37 and 74 g N/tree, respectively) with prebloom soil applications of ammonium nitrate supplying 75 or 150 g N/tree on fruit size, fruit set and total yield. Results indicate that foliar urea increased leaf N content during the first 48 hours following treatment regardless of pH.

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