Impact of deficit irrigation management and growth retardants application on yield attributes and yield of groundnut (Arachis hypogaea L.) variety VRI8

Groundnut, an important oilseed crop, requires effective management such as maintaining less oil moisture content and providing growth retardant chemicals to prevent pre-harvest sprouting, which can adversely affect yield. A field experiment was conducted at the Agricultural College and Research Institute, Madurai, in the early summer of 2024 to evaluate the impact of growth retardants and deficit irrigation on the sprouting of groundnut kernels. The study included three irrigation strategies: conventional irrigation and two deficit regimes with irrigation withheld from 90 to 105 DAS (Days After Sowing) and 85 to 100 DAS. Additionally, growth retardants [maleic hydrazide (MH) @ 1250 ppm, cycocel (CCC) @ 1000 ppm, abscisic acid (ABA) @ 750 ppm, and salicylic acid (SA) @ 750 ppm] were sprayed at 75 and 90 DAS. Results showed that MH @ 1250 ppm was the most effective treatment for inducing dormancy. A split-plot design was used. Withholding irrigation from 90 to 105 DAS also significantly increased pod yield by reducing pod loss due to field sprouting. The combination of MH @ 1250 ppm and no irrigation from 90 to 105 DAS resulted in a pod yield of 2776 kg ha-1, which was higher than the control plot. The foliar application of MH @ 1250 ppm combined with irrigation withdrawal from 90 to 105 DAS emerged as the most effective method for inducing dormancy in groundnut, resulting in a substantial reduction in pod loss and enhanced pod yield, as well as seed storage potential. The reduction in soil moisture content during the harvest stage, combined with changes in hormonal activities, significantly impacts seed sprouting. These factors can lead to stress conditions that inhibit germination, ultimately affecting crop yields. Addressing these issues is crucial for ensuring optimal seed development and enhancing agricultural productivity.