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Firstfruits

Tag: Citrus

25 Nov 2024
3 Comments By First Fruits Consulting Articles , , , ,

Fruit thinning chemical agents improves fruit size and quality in ‘kinnow’ Mandarin

‘Kinnow’ mandarin (Citrus reticulata Blanco) fruit needs to be thinned to increase the availability of photosynthates used to increase fruit size, fruit quality, profitability and can also help to overcome alternate bearing. This study evaluated ‘Kinnow’ fruit thinning using three chemical agents with different levels of concentration i.e. naphthalene acetic acid (NAA) @ 0.2, 0.3, 0.4, and 0.5 gL 1; 3,5,6 trichloro 2 pyridyloxyacetic acid (3,5,6 TPA) at TPA at 0.2, 0.5, and 0.7 gL 1, and ethephon @ at 0.4, 0.5, and 0.6 gL 1, in Pakistani orchards just after the June fruit drop for two growing seasons 2017 19. Fruit weight was increased due to chemical thinning application when compared with the respective controls.

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21 Oct 2024
Post harvest citrus
5 Comments By First Fruits Consulting Articles , , , , ,

Alternative methods for the control of postharvest citrus diseases

The postharvest diseases of citrus fruit cause considerable losses during storage and transportation. These diseases are managed principally by the application of synthetic fungicides. However, the increasing concern for health hazards and environmental pollution due to chemical use has required the development of alternative strategies for the control of postharvest citrus diseases. Management of postharvest diseases using microbial antagonists, natural plant-derived products and Generally Recognized As Safe compounds has been demonstrated to be most suitable to replace the synthetic fungicides, which are either being banned or recommended for limited use.

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21 Oct 2024
Girdling
6 Comments By First Fruits Consulting Articles , , , ,

Influence of girdling on the seasonal leaf nutrition status and fruit size of Robinson Mandarin

This study was undertaken to investigate the effects of single and double girdling applications on the fruit yield, commercial size, quality, photosystem II (PSII), leaf chlorophyll and leaf nutrition content of 22-year-old Robinson mandarin (Citrus reticulata). Girdling treatments were performed at anthesis (when 60% of the flowers were opened) with approximately 5 mm trunk diameter in 2014. The fruit was harvested in 2014 at the optimum harvest time (in December) for fruit yield, properties and size. Evaluations of leaf mineral content, chlorophyll concentration and fluorescence measurements were performed at monthly intervals.

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25 Aug 2024
Leaf Analysis
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Evaluation of the usefulness of early leaf analysis to improve nutrition management of citrus

The response of Citrus sinensis ‘Midknight’ (Nelspruit, Mpumalanga, South Africa) and Citrus paradisi ‘Orri’ (De Wet, Western Cape, South Africa) to excessive fertilisation (double the normal rate) with nitrogen (N), phosphorus (P), potassium (K) and magnesium (Mg) was investigated. The goal was to determine whether early-season leaf mineral compositions respond to fertilisation rates so that in-season adjustments of the fertilisation programme can be made.

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25 Jun 2024
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Short-term effects of cover crops on soil properties and the abundance of N-cycling genes in citrus agroecosystems

Limited information is available on the influence of cover crops (CCs) on soil nutrient cycling and the abundance of bacterial and archaeal communities, nitrogen (N)-fixers, nitrifiers, and denitrifiers in tree crops. We examined the effect of replacing the traditional weedy inter-row middle of a commercial citrus orchard in Florida with two different mixtures of CCs: legumes and non-legumes (LG + NL) and non-legumes only (NL). A no-treatment/grower standard was used as a control (GSC). After one year of CCs, the use of NL and LG + NL CCs significantly increased soil carbon (C) availability in the row middles compared to GSC as shown by increases in permanganate oxidizable C, and to a lesser extent, soil organic matter. Treatment with LG + NL significantly increased soil ammonium content compared to the NL and GSC treatments. Improved C cycling in soils treated with CCs was related to increased abundance of bacteria and archaea. Changes in the size of the soil N pool were accompanied by increases in the abundance of N-fixation (nifH) and nitrification (amoA) genes in soils treated with LG + NL, likely due to greater N-mineralization and N-fixation by legumes.

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24 May 2024
Citrus flower
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Demonstration of a Change in Nitrogen Metabolism Influencing Flower Initiation in Citrus

Changes in the leaf NH3-NH4 + content were monitored during floral induction in Citrus. Five-year-old rooted cuttings of ‘Washington’ navel orange (Citrus sinensis) were induced to flower by subjecting the trees to 8 weeks of low temperature, 8-h day (500 μE m−2 s−1) at 15–18°C/16-h night at 10–13°C and by transferring them afterwards to 12-h day (500 μE m−2 s−1) at 24°C/12-h night at 19°C. Maximum bloom occurred 4 weeks after the transfer to the warmer temperature. The number of flowers and the NH3–NH4 + content of leaves increased significantly (p < 0.05 and P < 0.01, respectively) with the length of the low temperature treatment. Sixteen-year-old ‘Frost Lisbon’ lemon trees (Citrus limon) on ‘Troyer’ citrange rootstocks (C. sinensis × Poncirus trifoliata) under commercial production were subjected to water-deficit stress of increasing severity.

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25 Jan 2024
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A Cost-Benefit Analysis for Crop Load

Generating profits in difficult conditions is one of the key drivers for sustainability in agriculture.

In recent years, some citrus producers have struggled to realise good returns as the industry faced a plethora of challenges. These challenges include, but are not limited to the cost of fertiliser, chemical, and fuel that rose rapidly because of the invasion of Ukraine, record freight rates and a decline in market prices.

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