The Effect of Root and Foliar Application of Selenium on the Growth and Yield of ‘Queen Eliza’ Strawberry in Hydroponic Culture

Document Type : Full Paper

Authors

1 Department of Horticultural Science, Faculty of Agriculture, Shiraz University, Shiraz, Iran

2 Department of Horticultural Science, Faculty of Agriculture, Shiraz University, Shiraz, Iran.

3 Department Horticultural Science school of Agriculture, Shiraz University, Shiraz, Iran

4 Department of Horticultural Science, Faculty of Agriculture, University of Guilan, Guilan, Iran

Abstract

Due to the elimination of soil in soilless cultivation and the lack of some beneficial elements in the nutrient solution, the application of these elements in soilless cultivation can effectively improve plant growth. This research was conducted with the aim of investigating the effect of root and foliar application of selenium on vegetative growth, fruit quality and yield of ‘Queen Elisa’ strawberry, using eight treatments and four replications in a completely randomized design.  The sodium selenate treatments were applied at four to five leaves stage as follows: foliar application at three different concentrations (2, 4, 6 mg.l-1) at two-week- intervals, root application at three different concentrations (1, 2, 3 mg.l-1) , foliar application (mg.l-1) along with root application (mg.l-1), and control treatment . The results showed that the most effective treatments were 1 and 2 mg.l-1 sodium selenate. The highest weight of fruits was obtained from the treatment with root applied-sodium selenite 1 mg.l-1, while treatment with sodium selenite 2 mg.l-1 showed more increase in the amount of anthocyanin and antioxidant activity of fruits. The highest amount of iron (Fe) and zinc (Zn) were found in the root applied-sodium selenite 1 mg.l-1 with 140.06 and 17.83 mg.kg-1 of dry matter, respectively. Consequently, in Queen Elisa strawberry under hydroponic conditon, the root application of sodium selenate at different concentrations had better results than foliar application.

Keywords

Main Subjects


Extended Abstract

Introduction

Selenium is a useful element for plants and essential elements for human health. A reliable strategie to  supply selenium requirement for humans is the bio-enrichment of fruits and vegetables with this element. Considering the soilless cultivation and the lack of some beneficial elements in the nutrient solution, using them can effectively improve plant growth. On the other hand, strawberry is one of the most delicious and popular small fruits that is widely produced throughout the year in soilless culture systems. This research was conducted with the aim of investigating the effect of two methods of selenium application , root and foliar, at different concentration on the growth and yield of Queen Eliza strawberry in hydroponic culture.

 

Materials and Methods

This research was conducted in the greenhouse of the Department of Horticultural Sciences, Faculty of Agriculture, Shiraz University in 2017. A commercial nursery situated in Kurdistan provided Queen Elisa strawberry cultivar. Daughter plants were planted in pots containing a mixture of cocopeat and perlite in a ratio of 1:1. The experiment was conducted for eight treatments and four replications in a completely randomized design. In plants at four to five leaf stages, sodium selenate was applied foliar at three concentrations (2, 4, 6 mg.l-1) at two-week intervals and root-applied at three concentrations (1, 2, 3 mg.l-1) together with the nutrient solution, combination of 2 mg.l-1 foliar and 1 mg.l-1 root application, and control treatment. The average day temperature in the greenhouse was 23±3 oC, the night temperature was 15±3 oC and the average relative humidity was 65%±5. In this research, the characteristics of leaf area, fresh and dry weight of roots and shoots, SPAD index, average weight, length and diameter of primary and secondary fruits, number of achenes, fruit yield, TSS, TA, vitamin C, free radical inhibition percentage (%DPPHs), total phenol, anthocyanin, chlorophyll a, b and total, carotenoids, ion leakage, nutrients such as Fe, Zn, N and Se were evaluated. Data were analyzed using SAS 9.2 software and means were compared using Duncan's multiple range test.

 

Results and Discussion

The results of this study showed that the most effective treatments were treatments 1 and 2 mg.l-1 sodium selenate. The highest chlorophyll was obtained in the 1 mg.l-1 sodium selenate in nutrient solution treatment.  Root application of 1 mg.l-1 sodium selenate resulted in the absorption of iron and zinc, as well as the highest concentration of carotenoid (4.69 mg.g-1 F.W.). Furthermore, the application of sodium selenate at 1 mg.l-1 resulted in the highest fruit weight (15.36 g) and length (37.97 mm). According to the results, the highest levels of anthocyanin and percentage of free radical inhibition were obtained with an average of 12.59 mg cyanidin glucoside/100 ml juice and 96.54 percent reduction of DPPHs, respectively, with 2 mg.l-1 sodium selenate. The highest TSS, TA and TSS/TA were obtained with the application of 2 mg.l-1 sodium selenate. Finally, the highest number of inflorescences, the number of achenes and average diameter of primary and secondary fruits were observed in the treatment with 3 mg.l-1 of sodium selenate. Foliar treatments had the highest selenium uptake in fruit and root. Thus, in this study, the root application had better results at different levels than the foliar application of sodium selenate.

 

Conclusion

Since selenium is an essential element in the human body and cannot be added to the foods directly, the bio-enrichment of products with selenium can be a source of supply of this element. Considering the purpose of the research, t he highest absorption of selenium in the strawberry fruit was observed in the treatment of 4 mg.l- 1sodium selenate foliar spraying , which does not have a negative effect on human health. In general, among the foliar spraying treatments, the 4 mg.l-1 treatment and among the root nutrition solution treatments, the 1 and 2 mg.l-1 treatments had the most positive effect and can be considered as the best treatments investigated in this research.

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