تأثير الصنف والرش بالبراسينولايد واضافة سمادHumzinc في بعض صفات النمو المظهرية والكيميائية لشتلات البرتقال

The effect of cultivar and spraying with brassinosteroids, along with the addition of Humzinc fertilizer on some morphological and chemical growth traits of orange Saplings

Abstract
The experiment was carried out in the certified Karbala Citrus Nursery / Horticulture Department / Ministry of Agriculture located in Al-Hindiyah District / Karbala Governorate. for the period from March to mid-October 2023, to study the response of orange seedlings budded on sour orange rootstock to spraying with the growth regulator Brassinolide and the addition of organic fertilizer Humzinc to the soil, and their interaction on some morphological and chemical growth characteristics.
An experiment was carried out with factorial (2*3*3) design using a complete randomized design with three replications. The first factor was the cultivars (Boold and Navel). The second factor was spraying with Brassinolide growth regulator at three concentrations (0, 0.3, and 0.6 mg L-1) , and the third factor was the addition of organic fertilizer Humzinc at three concentrations (0, 0.5, and 1 g L-1). The orange Saplings were sprayed with Brassinolide at three dates during the growth season on 15/3, 15/4, and 15/5/2023. Additionally, organic fertilizer was added to the soil at a rate of 250 ml per seedling in 6 installments starting from 16/3 until 16/8/2023
The results of this study can be summarized as follows:
1-The Blood cultivar outperformed the Navel cultivar in most morphological growth traits (main stem length, number of lateral branches, number of leaves, percentage of dry matter in the vegetative mass, root length, and volume) reaching (21.60 cm, 4.215 branches Sapling-1, 82.940 leaves Sapling-1, 36.810%, 73.260 cm, and 37.220 cm3) successively, while the Navel cultivar excelled in giving the highest significant increase in leaf area and percentage of dry matter in root mass (32.640 cm2 and 28.950%) successively.
2- The Boold cultivar distinguished itself from the Navel cultivar by recording the highest significant increase in leaf content of chlorophyll, carbohydrates, protein, and N, P, K, Fe, Zn, and Mn reaching (70.860 SPAD, 14.430%, 10.831%, 1.733%, 0.211%, 1.363%, 42.993 mg kg-1, 36.366 mg kg-1, 16.957 mg kg-1) successively.
3- The treatment of spraying with brassinolide growth regulator has a significant impact on the vegetative and root growth indicators. The treatment at a concentration of 0.6 mg L-1 surpassed in giving the main stem length and stem diameter, number of lateral branches, number of leaves, leaf area, leaves surface area, percentage of dry matter in vegetative and root mass, length and volume of the root (28.210 cm, 5.262 cm2, 4.622 branches Sapling -1, 91.460 leaves Sapling-1, 34.680 cm2, 3188 cm2, 46.140%, 32.970%, 93.560 cm, and 44.170 cm3) successively compared to the control.
4- As for the nutritional and mineral content of the leaves, treating them with 0.6 mg L-1 of brassinolide growth regulator led to the highest content of chlorophyll, carbohydrates, protein, and the mineral elements N, P, K, Fe, Zn, and Mn (78.230 SPAD, 15.450%, 12.715%, 2.034%, 0.223%, 1.448%, 44.923 mg kg-1, 38.126 mg kg-1, 19.087 mg kg-1) respectively, compared to the control treatment.
5- Application of organic fertilizer Humznic at a concentration of 1g L-1 showed a significant impact on all vegetative and root growth indicators, stem length and stem diameter, number of lateral branches, number of leaves, leaf area, leaves surface area, percentage of dry matter in vegetative and root mass, length and volume of the root (23.760 cm, 4.759 cm2, 4.422 branches Sapling-1, 85.050 leaves Sapling-1, 32.960 cm2, 2851 cm2, 41.720%, 31.380%, 83.720 cm, 40.670 cm3) successively compared to the control treatment.
6-As for the content of the leaves regarding chlorophyll, carbohydrates, proteins, and the mineral elements nitrogen, phosphorus, potassium, iron, zinc, and manganese, the treatment of adding organic fertilizer Humznic at a concentration of 1g L-1 gave the highest content reached (74.620 SPAD, 14.960%, 12.101%, 1.936%, 0.232%, 1.477%, 46.242 mg kg-1, 37.889 mg kg-1, 19.393 mg kg-1) successively, while the comparison treatment recorded the lowest values.
7- The binary and triple interactions between study factors led to a clear moral superiority in the studied characteristics compared to the control treatment. The triple interaction treatment (Blood cultivar + brassinolide conc. 0.6 mg L-1 + organic fertilizer Humic, conc. 1 g L-1) excelled in providing the highest moral increase in most indicators of vegetative and root growth, chlorophyll, carbohydrates, protein content, and mineral concentration in leaves compared to other treatments.
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