Influence of Chlormequat Chloride and Maleic Hydrazide on Yield and Yield Components of Rice (Oryza sativa L.)

Abstract

Rice productivity is often affected by climate variability and lodging, especially in coastal regions, leading to yield losses and poor grain quality. Plant growth regulators such as chlormequat chloride and maleic hydrazide are used to modify plant growth and improve assimilate distribution, lodging resistance, and yield performance in rice. A field investigation was carried out on rice during the rabi, 2020 - 21 at the wetland farm of S.V. Agricultural College, Tirupati, Andhra Pradesh. The goal was to study the effects of foliar application of maleic hydrazide and chlormequat chloride on rice yield and its attributes. The experiment followed a Randomized Block Design (RBD) with seven treatments and three replications. Twenty one day old rice seedlings were transplanted at two seedlings per hill. The treatments included control (T₁), maleic hydrazide at 5000 ppm (T₂), 10,000 ppm (T₃), and 15,000 ppm (T₄). It also included chlormequat chloride at 250 ppm (T₅), 500 ppm (T₆), and 750 ppm (T₇), applied as a foliar spray during the flowering stage. Observations on productive tillers, plant-1, grains panicle-1, filled grains panicle-1, grain yield, straw yield, and test weight were recorded and analysed statistically using ANOVA. Significant differences appeared among the treatments for all studied parameters. Chlormequat chloride at 500 ppm (T₆) showed the highest results for productive tillers plant-1 (10.00), grains panicle-1(185.33), filled grains panicle-1(173.66), grain yield (5248 kg ha⁻1), straw yield (7248 kg ha⁻1), and test weight (20.66 g). The untreated control had the lowest values for all yield attributes and parameters. The improved performance from growth retardant treatments resulted from better assimilate distribution, higher photosynthetic efficiency, and improved grain filling. The study concluded that foliar application of chlormequat chloride @ 500 ppm is an effective method to boost rice productivity.