Influence of Micronutrients and Plant Growth Regulators on Growth and Seed Yield of Cowpea [Vigna unguiculata (L.) Walp.]

The present study was carried out during the summer season of 2023–24 at the Vegetable Research Farm, Department of Horticulture (Vegetable and Floriculture), Bihar Agricultural College, Sabour, Bhagalpur, to assess the impact of varying levels of micronutrients and plant growth regulators (PGRs) on the seed yield and quality of cowpea (Vigna unguiculata (L.) Walp.). The experiment was laid out in a factorial randomized block design (RBD) with three replications and twenty five treatments. The treatments comprised five levels of micronutrients viz., M₀ (control), M₁ (Zn @ 75 ppm), M₂ (Zn @ 100 ppm), M₃ (Fe @ 100 ppm), and M₄ (Fe @ 125 ppm) and five levels of PGRs viz., P₀ (control), P₁ (GA₃ @ 100 ppm), P₂ (GA₃ @ 150 ppm), P₃ (NAA @ 50 ppm), and P₄ (NAA @ 75 ppm). Foliar applications were carried out at 35 and 60 days after sowing. Results indicated that the interaction treatment M₂P₂ (Zn @ 100 ppm + GA₃ @ 150 ppm) significantly enhanced yield attributes viz., seed yield per plant (20.94), pod length (35.28 cm), number of seeds per pod (11.08), 100 seed weight (17.77 g) and total seed yield (14.54 q/ha). However, plant height, number of branches, days to first flowering, 50% flowering, and first pod picking were not significantly affected. The M₄P₂ (Fe @ 125 ppm + GA₃ @ 150 ppm) treatment recorded the highest plant height (58.40 cm) and number of branches (5.90). Based on the findings, the M₂P₂ treatment emerged as the most effective combination for maximizing cowpea seed yield, highlighting its potential for improved seed production strategies.