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25 Mar 2023
Sweet orange with blossoms
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Rootstocks influence fruit oleocellosis in ‘Hamlin’ sweet orange

Oil spotting or oleocellosis, is a major problem in citrus crops. As the rootstock and fertilization play important roles in citrus growth and fruit development, we investigated the influence of different rootstocks on the growth, mineral nutrition metabolism, water relations, and fruit oleocellosis of eightyear-old field ‘Hamlin’ sweet orange trees. Trees grafted onto Lichi16-6 trifoliata (Poncircus trifoliate) had the greatest rate of oleocellosis (RO), and trees grafted onto Goutou orange (Citrus aurantium) had the greatest degree of oleocellosis (DO). In contrast, trees grafted onto Rangpur lime (Citrus limonia Osbeck) had the lowest RO and DO. Trees were the most vigorous on Rangpur lime rootstocks, followed by Lichi16-6 trifoliata, and then Goutou orange. In addition, because the scion/stock girth ratio showed significant correlations with the RO and DO, oleocellosis parameters can be a good indicator of scion/stock affinity.

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25 Mar 2023
Lemon covered in water
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Mid-long term effects of saline reclaimed water and regulated deficit irrigation on fruit quality of citrus

Non-conventional water sources and water saving techniques can become a valuable implement in semiarid regions, although its long-term effects on the citrus quality are little known. This study evaluated the effects of irrigation with two sources: transfer water (TW) and reclaimed water (RW) combined with two irrigation strategies: full irrigation (FI) and regulated deficit irrigation (RDI) on fruit quality response of mandarins and grapefruits during eight growth seasons. RESULTS: The RW irrigation in mandarin, without water restriction, determined maturity index (MI, SSC·TA-1) lower than in the TW-FI, owing to titratable acidity (TA) increased to a greater degree than soluble solid contents (SSC). Nevertheless, juice quality standards were satisfied. Besides, regardless of the irrigation treatment (FI or RDI), an increasing trend fruit weight was also detected by RW.

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28 Feb 2023
Citrus Thinning by hand.
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Thinning effects on Citrus Yield and Fruit Size

Thinning is performed in Citrus to increase fruit size and thus to enhance the market value of the crop. Fruit count is reduced and crop yield may be either unchanged or markedly reduced depending on the thinning procedure used.

The sink strength of the fruitlets, which determines fruitlet growth rate, is largely determined during the early stages of development. It may be increased reducing flower formation through the application of gibberellic acid during the winter rest period. In some cultivars this reduction in flower number results in an increase in the size of the ovaries and a faster early fruitlet growth rate. Also, the application of a synthetic auxin at flower opening increases selectively in most cultivars the sink strength of some of the ovaries. In both cases, the final number of fruits set is reduced in an indirect way and final fruit size is increased. Crop yield is not affected significantly.

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23 Jan 2023
Using gibberellic acid sprays on navel oranges
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Using Gibberellic Aid Sprays on Navel Oranges

The use of gibberellic acid (GA) is one of the most effective management tools available to citrus growers to improve rind quality and delay rind aging. Appropriate use of GA can result in better packouts and market outturns. Applying GA can be a costly exercise in terms of time and money, so it needs to be done right. this Primefact outlines how to get the most out of your GA sprays by providing information to help you decide when and how to apply GA to navel oranges.

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23 Jan 2023
Pre-harvest splitting of Citrus
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Pre-Harvest Fruit Splitting of Citrus

Under specific conditions, the fruit on citrus trees will split open. The damaged fruit is unmarketable and provides a habitat for fungal and insect pests that can reproduce and then damage currently marketable fruit. Losses of 30 to over 50 percent of the crop are possible with some cultivars. This is a physiological disorder that starts with nutrient imbalances at flowering that result in mechanically weak areas in the rind. These rupture if interior parts of the fruit expand faster than the peel can stretch.

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23 Jan 2023
Effect of Manual Fruit Thinning on Yield and Fruit Quality of Clementine Mandarin
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Effect of Manual Fruit Thinning on Yield and Fruit Quality of Clementine Mandarin

The effect of fruit thinning time and thinning rate on flowering, fruit yield and fruit quality of clementine trees (Citrus clementine Hort. ex Tanaka) was investigated during three successive seasons 2017/2018, 2018/2019 and 2019/2020. Data recorded only during 2018/2019 and 2019/2020 seasons. Thinning applied at three different times on 1st June, 15th June and 30th June. Fruit thinning rate were performed when the fruit diameter reached about 25-30 mm, as hand thinning by removing 0, 25 or 50% of fruit number/shoot per tree.

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25 Nov 2022
Fruit size in Star Ruby Grapefruit.
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The usage of auxins with various cultural techniques to increase fruit size in Star Ruby Grapefruit

Fruit size is a key parameter for quality and increases the profitability for export markets in citrus production in Turkey. Fruit size can be enhanced by several techniques such as girdling and thinning. Various plant growth regulators are known to affect the growth and size of citrus fruit. Thus the effects of synthetic auxin applications (2,4-DP and 3,5,6-TPA) at different physiological periods, girdling practices, pruning practices, foliar application of potassium and various combinations of these practices on the fruit size and yield, fruit retention rate, and leaf chlorophyll concentration and fluorescence of Star Ruby grapefruit cultivar were investigated.

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25 Nov 2022
Trunk girdling in Marisol Clementines.
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The effect of combined deficit irrigation and summer trunk girdling on the internal fruit quality of ‘Marisol’ Clementines

The influence of girdling, deficit irrigation, and a combination of girdling and deficit irrigation on fruit quality of ‘Marisol’ Clementines was investigated over two seasons, 1998 and 1999, at two different sites in South Africa. Girdling increased the total soluble solids (TSS) by 2-10%,however, the effect was not always significant. There were no trends observed for external fruit colour, fruit diameter, juice content (%), titratable acidity (TA) and TSS:TA ratios due to girdling.

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