Investigating the use of chitosan on yield and some quality characteristics of tomatoes

Introduction:

 Chitosan is a biological polymer that is obtained from the chitin of crustaceans, fungi and Arthropoda, and is the most abundant polysaccharide on the earth's surface after cellulose (5). According to some evidences that indicate the improvement of the quality of plant products by chitosan, studying and understanding the effect of chitosan bio stimulant spraying on the quantitative and qualitative performance of important plants such as tomatoes has particular importance in agricultural research.

Materials and Methods:

 was done in order to investigate the effect of chitosan bio stimulant on the growth and yield and some quality characteristics of tomato fruit in a factorial format based on a randomized complete block design with three replications in two crop years 2017-2018 in fields belonging to Dasht Sabz Company, Kasht Complex and the RoginTak industry located in the Iran, Kermanshah. In this experiment, the chitosan bio stimulant was evaluated at five levels (control(S0), 1/1000(S1), 2/1000(S2), 3/1000(S3), and Seed coating(K) treatment). The experiment included 15 plots, each plot with a length of 4.2 meters and a width of 2.1 meters. Three rows were planted in each plot and 7 plants in each row and 21 plants in each plot. The distance between the rows was 1.4 meters and the distance on the row was 30 cm. In total, 315 plants were cultivated in this experiment. The planting density was about 2.38 plants per square meter or 23800 plants per hectare. Analysis of total data was collected using MSTAT-C statistical software. 

Results and Discussion:

 The results of analysis of variance showed that the effect of chitosan spraying on all studied traits was significant, the highest yield was obtained in the S3 treatment in the second year with the amount of 227tons per hectare. Chitosan spraying in the first and second year increased the yield compared to the treatment. It was seen that in the first year, in the treatments of S1S2, S3 and K, it caused an increase of 20, 27, 47 and 31% respectively, and in the second year it caused an increase of 11, 14, 15 and 1% performance compared to the control (S0) treatment. The highest amount of fresh weight was observed in the treatment of S3. The highest amount of dry weight in the treatment of S2 was 399 grams in the second year, which was significantly different from other treatments, which had a significant difference with other treatments so that in the K treatment compared to the S0, S1, S2, and S3 increased the acidity by 6, 3, 5 and 3%, respectively.The effect of chitosan treatment increased the amount of TSS compared to the control treatment. So that the effect of S1, S2, S3 and K treatments caused an increase of 7, 4, 3 and 10% in the amount of TSS, respectively, compared to the S0 treatment. The percentage of nitrogen on average in the first and second year in the S2, S3 and K treatments was higher than the S0 treatment and this increase was 5, 6 and 1%, respectively. However, in the S1 treatment, this value was less than the S0 treatment (13%). The highest percentage of potassium in the treatment of S2 in the first year was 4.62%. On average, in the treatments of S1 and S2, chitosan foliar spraying increased the amount of potassium by 1 and 15% compared to the S0 treatment. In the treatments of S3 and K, it caused a decrease in the amount of potassium compared to the S0 treatment. The highest percentage of phosphorus in the S1 treatment in the first year was 0.65%, in the first and second year in the S3 treatments and K increased the amount of phosphorus by 9% and 2%, respectively, compared to the S0 treatment. Although, in the S1 treatment. no difference was observed, in the S2 treatment, the amount of phosphorus decreased by 9% compared to the S0 treatment, the highest percentage of calcium was obtained in the S1 treatment in the first year, and the lowest amount of calcium was observed in the second year in the K treatment. Chitosan foliar spraying in the S1 treatment caused an 82% increase in the amount of calcium compared to the S0 treatment. The average comparison results showed that the highest amount of sodium in the S3 treatment in the second year was 0.275 ppm. On average, in the S3 and S2 treatments, chitosan foliar spraying caused an increase of 5 and 11% in the amount of sodium compared to the S0 treatment, but in the treatments of S1 and S2, it caused a decrease of 2 and 15% in the amount of sodium compared to the S0 treatment. The highest amount of ascorbic acid in the S3 treatment was 0.45 PPM, which was significantly different from other treatments. The lowest amount of ascorbic acid was 0.306 PPM in the S2 treatment. except for the S2 treatment, which caused a 9% decrease in the amount of vitamin C, in the S1, S3 treatments, and K increased by 14, 33, and 29%, respectively, compared to the S0 treatment.

Conclusion:

The results of this experiment investigated the effect of chitosan on the growth and yield and some quality characteristics of tomato fruit. Based on the obtained results, the use of chitosan as a biological stimulant improves yield, fresh weight, dry weight, and dissolved solids. And it became ascorbic acid. However, in the case of nitrogen, phosphorus, potassium, sodium and calcium elements, there was no linear trend in the increase of elements. However, in general, chitosan foliar application increased the percentage of the investigated elements compared to the S0 treatment. So that the greatest effect in increasing yield, plant fresh weight, nitrogen, phosphorus and ascorbic acid was observed in the S3 treatment, also the highest amount of PH, TSS and sodium was observed in the K treatment, the highest amount of dry weight and potassium In the S2 treatment and the highest amount of calcium was observed in the S1 treatment.