Source-sink regulation in red gram through foliar nutrition of potassium and growth promoters in the warm humid tropics of Kerala

The study was conducted to assess the influence of potassium and growth regulators on the source-sink efficiency in red gram [Cajanus cajan (L.) Millsp.]. The field experiment was laid out at College of Agriculture, Vellayani during 2019-2021 with combinations of four levels of potassium (0.5 % K₂SO₄, 1.0 % K₂SO₄, 0.25 % KNO₃, 0.5 % KNO₃) and three growth regulators (gibberellic acid 75 mg kg^-1, brassinosteroid 0.1 mg kg^-1 and humic acid 100 mg kg^-1) as treatments, along with a control of conventional practice with no foliar nutrition. Foliar application of KNO₃ and GA₃ significantly enhanced the growth attributes. Seed yield (1081.33 kg ha^-1) and haulm (4837.27 kg ha^-1) yields were superior with foliar application of KNO₃ (0.5 %) and GA₃. The interaction effects of KNO₃ (0.5 %) × GA₃ revealed the significantly highest values for yield attributes and seed yield revealing efficient source-sink regulation compared to the conventional practice of sole nutrient application in soil.