Effect of Plant Growth Promoters and Herbicides on Growth, Yield Attribute and Yield of Kharif Hybrid Maize (Zea mays L.)

A field experiment was conducted during two consecutive kharif seasons 2022 and 2023 at Students’ Instructional Farm, Department of Agronomy, Chandra Shekhar Azad University of Agriculture and Technology, Kanpur, (U.P.) - 208002 India. The experiment was laid out in split plot design with three replications. Three plant growth promoters [viz. Gibberellic acid (P1), Cytokinin + Enzymes (P2) and Amino acid + Humic acid + Sea weed extract (P3)] were allocated in main plots; whereas six herbicidal treatments [viz. Weedy check (W1), Tembotrione 42%SC @ 120g a.i./ha (W2), Halosulfuron methyl 75% WG @ 72g a.i./ha (W3), Topramezone 33.6 SC @ 25.2g a.i./ha (W4), Atrazin 50%WP @ 1kg a.i./ha (W5) and Mesotrione 2.27%W + Atrazin 22.7%SC @ 750 ml a.i./ha (W6)] were setup in sub plots. On the pooled basis of two years experimental results showed that, application of Amino acid + Humic acid + Sea weed extract (P3) recorded significantly highest value of plant height (208.22cm), crop growth rate (47.54 and 9.96 g m-2 day-1 at 60 - 90 DAS and 90 DAS - harvest stage, respectively), relative growth rate (0.1029, 0.1052 and 0.0825 g g-1 day-1 at 30 - 60 DAS, 60 - 90 DAS and 90 DAS - harvest stage, respectively), length of cob (18.56cm), number of grains cob-1 (574.01), grain yield (6835.95 kg ha-1) and harvest index (34.26). However, among herbicidal treatments, Tembotrione 42%SC @ 120g a.i./ha (W2) was recorded significantly maximum weed control efficiency (85.86% at 75 DAS) plant height (216.59cm), leaf area (5226cm2) crop growth rate (43.45, 48.77 and 10.26 g m-2 day-1 at 30 - 60 DAS, 60 - 90 DAS and 90 DAS - harvest stage, respectively), relative growth rate (0.1037. 0.1053 and 0.0829 g g-1 day-1 at 30 - 60 DAS, 60 - 90 DAS and 90 DAS - harvest stage, respectively) and net assimilation rate (5.65 g m-2 day-1 at 30 - 60 DAS), length of cob (18.56cm), number of grains cob-1 (574.01), grain yield (6835.95 kg ha-1) and harvest index (34.26).