Study on the Effect of Calcium and Potassium Spray on Date Bunch Fading Disorder

علوم باغبانی

Article 14, Volume 30, Issue 3, September 2016, Pages 358-365   

Document Type: Research Article

DOI: 10.22067/jhorts4.v30i3.24860

Authors

Hosein Shekofteh^* ; Mohammad Nick-Pour

Vali-e-Asr University of Rafsanjan

Abstract

Introduction: Date bunch fading disorder has been one of the most important problems, which caused economic damage to date plantation area of Iran. It has been first reported on Mozafti cultivar in Kahnuj area, Kerman province. It has often been observed on soft and mid ripening cultivars such as Mozafti, Mordaseng and Kalote. Furthermore, it usually appears on Mozafti cultivar when fruits change from Khalal to Rutab stage. The most important symptoms of this disorder are sudden wilting of fruits and necrotic strips on the upper surface of the main bunch stalk. Incidence and development of these symptoms increase by high temperature, low relative humidity, and hot and dry wind. Several research studies have been carried out on this disorder so far, but the only research about the effect of nutrition on disorder was performed by Rosta (2003). The aim of the present study was to investigate the effect of calcium and potassium spray on date bunch fading and some traits of date fruit in Rigan region, Kerman province.
Materials and Methods: The experiment was conducted based on randomized complete block designs with three replicates in Rigan located in east south of Kerman province, Iran, in 2012. Treatments were: T1: control, T2: spray of calcium nitrate at the concentration of 5 ppm, T3: spray of potassium sulfate at the concentration of 5 ppm, and T4: combined spray of calcium nitrate and potassium sulfate at the concentration of 5 ppm. Treatments were applied at Kimri, Hobabok and Khalal stages. Sampling was performed from 3 date palms (3 bunches from each date palm were selected randomly) at the second date harvest. Totally, the traits of 200 fruits were measured in each date palm. The traits measured in the present study were: fruit length, fruit diameter, fruit weight, stone weight, stone diameter, and bunch fading percentage.
Results and Discussions: According to the data of variance analysis, treatments had a significant effect on wet fruit weight, fruit length, fruit diameter, stone weight, stone diameter, and bunch fading percentage at 1℅ level. The highest wet fruit weight, fruit length, fruit diameter, stone weight, and stone diameter were attained in the treatment containing combined application of calcium nitrate and potassium sulfate. Furthermore, the lowest amounts of these traits were obtained in control. The lowest and highest percentage of date bunch fading belonged to the combined treatment of calcium nitrate and potassium sulfate, and control, respectively. In general, application of calcium nitrate and potassium sulfate with each other improved fruit traits and reduced bunch fading percentage. Calcium mobility in the plant takes place mainly in the xylem, together with water. Therefore, calcium uptake is directly related to plant transpiration rate. Conditions of high humidity, cold and low transpiration rates may result in calcium deficiency. Salinity might also cause calcium deficiency because it decreases water uptake by the plant. Since calcium mobility in plants is limited, calcium deficiency appears in younger leaves and in fruits, because they have a very low transpiration rate. Therefore, it is necessary to have a constant supply of calcium for continued growth. Calcium deficiency is usually caused by low calcium availability or water stress which results in low transpiration rates. Calcium is an essential plant nutrient with many roles including participation in metabolic processes of other nutrients uptake, promotion of proper plant cell elongation, and improvement of cell wall structure – calcium is an essential part of plant cell wall. It forms calcium pectate compounds which give stability to cell walls and bind cells together. It also helps protecting the plant against heat stress - calcium improves stomata function and participates in induction of heat shock proteins. In addition, it helps protecting the plant against diseases - numerous fungi and bacteria secret enzymes which impair plant cell wall. Stronger cell walls, induced by calcium, can avoid the invasion of diseases. Considering the important roles of calcium, calcium spray increased thetraits of date fruit and decreased bunch fading percentage. As an important element in photosynthesis, , potassium regulates the opening and closing of stomata, and therefore regulates CO2 uptake. Potassium plays a major role in the regulation of water in plants (osmo-regulation). Both uptake of water through plant roots and its loss through the stomata are affected by potassium. Moreover, protein and starch synthesis in plants requires potassium, so that the enzymes responsible for starch synthesis are activated by potassium. Potassium has also an important role in the activation of many growth related enzymes in plants. Results of the analysis of the studied soil showed that available potassium content in soil was less than plant requirement. So spraying of potassium sulfate could result in the improvement of date fruit traits and reduction of bunch fading disorder. Finally, combined spray of calcium and potassium caused a significant reduction in date bunch fading percentage.
Conclusion: The results of the present study indicated that spray of calcium and potassium solely improved fruit traits and bunch fading disorder, but maximum values of fruit yield components and minimum bunch fading percentage obtained from foliar spray of calcium and potassium together.

Keywords

Calcium nitrate; Date disorders; Leaf nutrition; Potassium sulfate

References

1- Abazarpour M., Basirian A. 1997. Determination of Date Palm Cultivars of Kerman Province (Volume 1: Jiroft, Kahnuj, Bam, and Shahadad). Agriculture Organ of Kerman province press, 21 pp.

2- Ashraf Jahani A. 2002. Date is Live Fruit. Agriculture Sciences Press, 147 pp.

3- Balali M.R., Malakoti M.J., and Amir Makri H. 2001. Production and optimal application of fertilizer to sustainable agriculture. Agriculture Training Press, Karaj, Iran.

4- IzadiM. 2002. Effect of time and type of bunch covers on date bunch fading disorder in Bosher province. 8th Date conference, Bam, Iran.

5- Javaheri A., andMusaviFazl M. 2002. Study on the effect of micronutrients on date quantity and quality. 8th Date Conference, Bam, Iran.

6- Kardavani P., Ezetian V., Amandadi N. 2013. An investigation of the effects of climatological factors, UV radiation and ozon on the bunch of Mozafatidate dryness basad on neural artificial networks and main component regression (Case Study- Jiroft). Journal of landscape geography, 10(1): 1-14. (in Persian with English Abstract).

7- Marschner, H. 1995. Mineral Nutrition of Higher Plants. 561. Academic Press, Sydney.

8- Mohamadi H.M., and MoghtadariGh.A. 2005. The relationship between climatic elements and necrosis of date palm bunch using regression model. Desert, 10(2): 339-348. (in Persian with English Abstract).

9- Najafinia M., and Azadavar M. 2002. Isolation some fungi spices of fading disorder infected bunchs in Jiroft, Kahnuj, and Bam area.8th Date conference, Bam, Iran.

10- PanahiKh. 2001. An overview on date bunch fading disorder reasons. Zitone Agricultural Magazine, 144: 46-51. (in Persian).

11- Pezhman H. 2001. Date Palm Guidance. Agriculture Training Press. 286 pp.

12- Pezhman H. 2002. A view on date palm situation and its research program in IRAN. Proceeding of Date Palm Global Network Establishment Meeingt. UAE Univ. Al Ain. 71-80.

13- Pezhman, H., and Roshan H. 2012. Evaluation of bunch fading disorder reasons in Bam region. Iranian Date Conference, Kerman, Iran.

14- Pezhman. H., Roshan V and Rahkhodaei E. 2003. Effects of cultural practices on date bunch fading disorder. Abstracts of the international conference on Date palm. King Saud University. 46p.

15- Rosta M. J. 2002. Effect of potassium sulfate and calcium chloride application with and without microelements on date bunch fading disorder. 8th Date conference, Bam, Iran.

16- Rosta M.J. 2003. Effect of foliar spray of potassium sulfate and calcium chloride on date bunch fading disorder. Soil and Water journal, 17: 123-130. (in Persian).