Effect of plant spacing and some growth regulators on growth, yield and antioxidant activity of flax

• Zahraa Abdel Karim Mazhar1*, Maher H. S. Al-Mohammad2 and Rafid Saleh Nahhab3

  Author

A field experiment was conducted during the 2024 growing season at the Umm Gharagher Horticulture and Nursery Development Station of the Karbala Agriculture Directorate, on the effect of plant spacing and some growth regulators on the growth, productivity and antioxidant activity of flax plants. The studied factors included: Plant spacing between plants (5 cm and 15 cm), spraying of growth regulators (distilled water, IAA at a concentration of 2 mg L-1, GA at a concentration of 200 mg L-1, and their combination). The results showed the superiority of the 15 cm plant spacing as the highest plant height was 87.25 cm, number of main branches 13.70 branches plant-1, stem diameter 1.9667 mm, number of leaves 124.85 leaves plant-1, leaf area 0.9303 cm2, total chlorophyll content 5.261 mg 100 g-1 fresh weight, number of capsules 36.72 capsules plant-1, weight of 1000 seeds 8.556 g, total seed yield 2.669 t ha-1, oil percentage 34.944%, total oil yield 94.4 kg ha-1, total phenols 15.17 mg g-1 dry weight, total flavonoids 9.55 mg g-1 dry weight, total carotenoids 2.784 mg g-1 dry weight, total antioxidant activity 62.44% ABTS inhibition, and free radical scavenging efficiency 66.07%. The combination treatment between IAA and GA3 also outperformed and achieved the highest number of main branches 19.42 branches plant-1, number of leaves 154.92 leaves plant-1, total chlorophyll content 5.332 mg 100 g-1 fresh weight, number of capsules 46.06 capsules plant-1, weight of 1000 seeds 9.790 g, total seed yield 3.548 t ha-1, oil percentage 35.283%, total oil yield 125.4 kg ha-1, total phenols 16.06 mg g-1 dry weight, total flavonoids 10.25 mg g-1 dry weight, total carotenoids 2.960 mg g-1 dry weight, total antioxidant activity 63.45% ABTS inhibition and free radical scavenging efficiency 67.58%. The P15 x IAA2 + GA200 interaction treatment achieved the highest number of main branches 19.94 branches plant-1, number of leaves 159.80 leaves plant-1, number of capsules 49.05 capsules plant-1, weight of 1000 seeds 10.407 g, total seed yield 3.822 t ha-1, oil percentage 36.090%, total oil yield 137.9 kg ha-1, total phenolics content 17.24 mg g-1 dry weight, total flavonoids 11.33 mg g-1 dry weight, total carotenoids 3.241 mg g-1 dry weight, total antioxidant activity 64.30% ABTS inhibition and free radical scavenging efficiency 68.80%.

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