Boron supplementation enhances yield, photosynthetic efficiency, enzyme activity, and mineral content in Persian clover (Trifolium resupinatum L.).

Persian clover is an important forage crop cultivated worldwide. Different management practices are being explored to enhance the productivity of Persian clover. The current study explored the beneficial role of boron on growth, yield, nutrient content, and biochemical activities of Persian clover. The experiment was conducted using seven boron foliar treatments at concentrations of 0, 3, 6, 9, 12, 15, and 18 ppm. Plant fresh weight, plant dry weight, plant height, number of leaves, number of stems, and leaf area were enhanced by 3 and 6 ppm boron. Photosynthetic pigments were improved under 3 and 6 ppm boron, whereas other concentrations caused a reduction in photosynthetic pigments due to boron toxicity. Plant biochemical activities were enhanced by supplementation with 3 and 6 ppm of boron. Boron toxicity also occurs at higher concentrations (9, 12, 15, and 18 ppm), resulting in higher malondialdehyde (MDA) production. Moreover, higher concentrations (9, 12, 15, and 18 ppm) suppressed growth, reduced yield, leading to a decline in photosynthetic pigments, and decreased macronutrients levels. A correlation matrix and heatmap were used to evaluate the relationships between the studied traits, indicating that, 3 and 6 ppm boron are the optimum doses for sustainable production of Persian clover.