Citrus creasing is an alteration that is characterized by the formation of fissures in the inner soft part of the citrus rind
This problem can affect production up to thirty percent decreasing its quality and in turn, its commercial value has been one of the main problems faced by orange growers. Creasing makes fruit fragile for handling and reduces the capacity of the fruit to be stored or transported.
It is known that claret originates in the first phase of fruit development after fruit set, and the first symptoms are detected in albego cells, the cause of this is associated with:
- Climate Factors like cool springs, humidity fluctuations, water stress followed by high moisture.
- Genetic factors some varieties have greater sensitivity as Navelinas, W. Navel, Valencias, Clementinas, Novas, Nadorcots, and Fortune.
- Nutritional Factors: Increased nitrogen and phosphorus fertilization and low potassium increase their incidence.
Calcium levels are strongly related to citrus creasing as well as the deficiency of other nutrients in specific cases.
Cell Wall Calcium is a diagnostic tool to evaluate quality parameters related to the appearance of the product, as well as its commercial life. In certain matrices, total Calcium, with limits of quantification adapted to the fruit, is also an exceptionally reliable marker when evaluating some specific alteration.
Calcium favors the formation of a more elastic skin that will result in greater resistance, there are countless formulations based on calcium, it is convenient to opt for those of higher quality since they will be the most assimilable by the plant.
The type of soil and soil texture, good cultivation practices, water stress during hot days can positively or negatively influence the presence of creasing. The fertilization must be balanced and dividing the nitrogen contributions and ensuring good levels of potassium and calcium in the fruits. Irrigation must be uniform, avoiding water stress that can induce creasing.
Ensuring that our irrigation system works correctly, filters, pressure, clogging of drippers, are factors that can reduce the efficiency of our irrigation system, reducing its efficiency by up to 75%, leaving our crop in a situation of continuous water stress.
There are treatments to delay the appearance of creasing, but they will not prevent its presence which will allow a longer period of commercialization of the fruit. Under the diagnosis and supervision of a professional, the applications of gibberellic acid have given good results in orange-producing countries.
Cell Wall Calcium
AGQ Labs has developed a state-of-the-art analysis of the Cell Wall Calcium fraction in fruit, a good tool for diagnosing alterations in pre- and post-harvest quality.
It is well known that post-harvest is a key period with a direct influence on the quality and appearance with which fruits and vegetables reach their point of sale. Even if we have done a superb job in the field, if the product does not successfully endure the period between harvest and sale, we will have failed.
Several factors have a bearing in this process. One factor with a major role is tissue calcium content. Calcium’s structural function is directly related to plant tissue stability and thus to the product’s post-harvest behavior (rotting, brown spots, loss of consistency, etc.), as well as its probability of being affected by pre-harvest damage (creasing in citrus fruit, cracking in stone fruits, bitter pit in apples, etc.).
In addition to having a structural function (for cell wall bound calcium in the form of calcium pectates), calcium is involved in other functions in plant cells. It is thus also found in other plant parts, as soluble calcium in the apoplast and symplast (in the form of nitrates, chlorides and amino acids), insoluble calcium in form of precipitates in the vacuoles (mainly in the form of phosphates, carbonates and oxalates) and residual calcium in highly insoluble forms (mainly).
Cell Wall Calcium is a diagnostic tool for evaluating quality parameters related to the appearance and market life of the product. And in certain matrices, total calcium, with quantification limits adapted to the fruit, is also a very reliable marker for assessing several concrete alterations.
Contact our Agronomy team for more information.