Ethrel and GA3 Induced Physio-biochemical Alterations in Sugarcane for Manoeuvring the Biometric Traits for Enhancing Cane and Sugar Yield

Background: Physiological growth of sugarcane crop is restricted by high temperature and limited growth period. This causes considerable reduction in crop and sucrose yield. Improving physiological growth within the limited period is therefore highly desirable. Methods: Field experiment was undertaken in 2021-2023 for determining the effect of exogenous applications of Ethrel (100 ppm) and Gibberellic acid (35 ppm) on germination, shoot population, physiological characteristics, dry matter and sucrose contents. Sugarcane setts were soaked overnight in Ethrel before planting and foliar application of GA3 was conducted at 90, 120 and 150 days after planting (DAP). Result: Ethrel soaking led to 100% sprouting and high settling population at 20 DAP. Early sprouting increased the growth period to 285 days as compared to 240 days in control. The applications increased leaf area (55%). The changes led to increased shoot numbers (28.3%), internodal numbers stalk-1 (41.02%), internodal length (42%), internodal girth (45.15%) and stalk length (45%) at harvest stage. The stimulated physiological growth augmented the dry matter content, oBrix and purity of cane juice by 24.2%, 3% and 0.3% respectively. The study demonstrates that higher shoot population together with increased LAI and stalk elongation during the growth period, both induced through Ethrel soaking and Gibberellic acid applications, are positively associated with increased dry matter and sucrose contents.