The Effect of Calcium to Magnesium and Potassium Ratios on the Productivity and Fruit Quality of Tomato Grown in Hydroponics

Sara Sarko(1) and Ghiath Ahmad Alloush*(1)

(1). Department of Soil and Water Sciences, Faculty of Agriculture, Tishreen University, Latakia, Syria.

(* Corresponding author: Dr. Ghiath Ahmad Alloush. E-mail: galloush@scs-net.org).

Received: 24/07/2018                                Accepted: 12/11/2018

Abstract

A hydroponic experiment was conducted in a greenhouse during the spring-summer seasons of 2015 to investigate the effect of various ratios of Ca:Mg (4:6, 5:5, 7.5:2.5 and 10:0.5 mM/L-1) and potassium (0.5, 3, and 4.5 mM/L-1) on total fruit production, marketable fruits and quality of tomato fruits (cv. Shannon).  The experiment consisted of 12 treatments with three replicates. Pots were completely randomized on the experimental plot. The results showed that the highest fruit production reached 4.72 kg/plant (fruit yield of 5 punches) in the treatment Ca:Mg (7.5:2.5) and 3 mM/L-1 K. Physiological disorder symptoms on fruits along with small size (< 47 mm) decreased the percentage of marketable fruit production to 8% of total in treatment Ca:Mg (5:5) and 0.5 mM/L-1, whereas marketable fruit production were 95% in the same Ca:Mg ratio but 4.5 mM/L-1 K. pH dropped in fruits with increasing Ca:Mg ratios at all K concentrations in the nutrient solution. The decrease pH values became significant in Ca:Mg ratio (7.5:2.5) and 10:0.5. The reverse was true with total titratable acidity. TSS increased as Ca increased in the nutrient solution if K supply was adequate (4.5 mM), and reached 65.2 mg/g in the treatment Ca:Mg ratio (10:0.5). Vitamin C concentrations took the same trend as TSS, and values were between 30-45, which were higher than normally reported (15-25 mg/100 g). Nitrate concentrations, while increasing with increasing Ca and K concentrations in the nutrient solutions, were within normal range (less than 400 mg/L-1)

Key words: Tomato, Hydroponic culture, Fruit yield, Vitamin C; Total acidity, TSS, pH, NO3.

Full Paper in Arabic: PDF

Determination of the Optimum Laboratory Conditions for the Production of Crystal Protein by Bacillus thuringiensis KS3 Isolated from Iraqi Soils

Khlood Abid-Alelah Alkhafaji*(1) Samera Oda Khleoy(2) Safaa Abid Alrahem Mahmoud(1) Shaemaa Rajab Farhan(1) Sabreen Abid Alhadi Saleh(2) and Mohamed Abid al- Rahem Abiallah(1)

(1). Applied Microbiology Department, Center of Biotechnology, Directorate of Agricultural Research, Ministry of Science and Technology. Iraq.

(2). Biology Control Department, Pest Integrating Management Center, Directorate of Agricultural Research. Ministry of Science and Technology. Iraq.

(*Corresponding author: Khlood Abid-Alelah Alkhafaji. E-Mail: khloodalkhafaji@yahoo.com).

Received: 15/03/2018                                Accepted: 25/09/2018

Abstract

This research aimed to determine the optimum conditions for the production of crystal protein produced by a local Iraqi isolate of Bacillus thuringiensis KS3. This research was conducted at the laboratories of Directorate of Agricultural Research during the period from 2016 to 2017. Growth factors such as sugar, nitrogen sources and minerals were evaluated, also pH was determined. Environmental factors such as temperature, aeration and time of production were studied separately; Laurea Bertani broth (LB) was modified for optimal production of crystal protein. Sucrose gave the best concentration of protein which reached up to 4.49 mg/ml, while peptone could be used as a substitute of a tryptone as best nitrogen source. No significant differences among tryptone, soytone, beef extract and casein. The best C:N ratio was that of 2% peptone and 1.5% sucrose which gave 5.252 mg/ml. Magnesium sulfate increased the crystal protein concentration which reached to 7.92. No significant difference was observed between magnesium sulfate and manganese chloride. Medium equilibrated to pH 7.5 was used for highest crystal protein production compared with pHs 6.5, 7, and 8. Culture of Bacillus thuringiensis KS3 incubated for 72 h at 30C with 120 rpm/min in a shaker incubator gave the best protein concentration.

Key words: Bacillus thuringiensis, delta toxin, sucrose, peptone, pH.

Full paper in Arabic: PDF