Effect of seed treatment and foliar spray with biochar on plant growth and seed yield of French bean (Phaseolus vulgaris L.)

French bean (Phaseolus vulgaris L.) is an important leguminous vegetable crop valued for its high nutritional content and economic importance. The present study was conducted during Rabi 2024-25 at the Postgraduate Research Block, College of Agriculture, University of Agricultural Sciences, Raichur, to evaluate the effect of seed treatment and foliar spray with biochar on the growth and yield of french bean. The experiment was laid out in a Randomized Complete Block Design with ten treatments replicated thrice, including control, seed treatments and foliar applications of biochar (300 and 500 mg/L), humic acid (2.5 mL/L) and their combinations, along with a common foliar spray of vegetable special @ 5 g/L. Growth and yield parameters were recorded at different crop stages. The results revealed that foliar spray of biochar @ 500 mg/L (T₅) significantly enhanced plant growth and yield attributes compared to the control. T₅ recorded maximum plant height at 30, 60 DAS and harvest (33.68, 46.33 and 40.18 cm, respectively), number of branches per plant (7.53), pod length (15.27 cm), and pod width (1.56 cm) higher than control. Early flower bud initiation (36.06 days), 50% flowering (41.66 days) and maturity (71.38 days) were observed in T₅, indicating accelerated phenological development. The same treatment recorded the highest number of clusters per plant (9.90), pods per plant (27.25), seeds per pod (6.40), and seed yield (901.00 g plot⁻¹ and 19.06 q ha⁻¹) compared to the control (T₁, 754.66 g plot⁻¹ and 17.00 q ha⁻¹). The study concludes that foliar application of biochar @ 500 mg/L effectively improves growth, earliness and yield of french bean, demonstrating its potential as a sustainable and efficient crop management practice.