Evaluation of defoliants and detection of its residues as harvesting aids in greengram (Vigna radiata L.)

Abstract

A experiment was conducted at Regional Agricultural Research Station, Warangal (18oo3ʹ, 79o22ʹ and 270 m AMSL) Telangana, India during Kharif (June-September, 2015 and 2016). The defoliants Glyphosate @ 8 ml/l + Ammonium sulphate @ 8 g/l; Paraquat @ 4 ml/l; urea @ 200 g/l; ZnSo4; MnSo4; and Mncl each @ 30 g/l with water as control were sprayed on greengram at physiological pod maturity. The designated seven treatments were imposed in Randomized Block Designed and replicated thrice. Leaves count/m2 was taken before and at 3, 5, 7 and 10 days after defoliants spraying. The harvested seed were tested for germination percentage. Spraying of paraquat @ 4 ml/l at Physiological pod maturity caused drying and fall of greengram leaves to 92 percent by the 3 days after defoliants spraying and 100 percent by the 7 days after defoliants spraying, followed by glyphosate @ 8 ml/l which influenced the defoliation to 93 percent by the 7 days after defoliant spraying and 99 percent by the 10 days after defoliant spraying. There paraquat and glyphosate were significantly superior to control as well as other defoliants. Increased work efficiency because of less interference of leaves in harvesting of pods. Defoliants traces were not detected in grain and plant, and the germination percentage of seed was also not affected. The research study indicated possibility of defoliants as harvesting aids in greengram as they are easily available and are without any residues.