Use of stress reducer and subdoses of 2,4-D in cotton crop development and yield

• Grant number: 24/13640-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: October 01, 2024
• End date: September 30, 2025
• Field of knowledge: Agronomical Sciences - Agronomy - Crop Science
• Principal Investigator: Samuel Ferrari
• Grantee: Murilo Sampaio Bassi Janegitz
• Host Institution: Faculdade de Ciências Agrárias e Tecnológicas. Universidade Estadual Paulista (UNESP). Campus de Dracena. Dracena , SP, Brazil

Abstract

The cotton crop production cycle is considered intermediate to long and lasts from 140 to 220 days depending on the cultivar used, type of sowing, local climate, conditions of the area where the sowing will take place and mainly the technologies involved in the process. During development, the culture can go through periods of biotic and abiotic stress and the use of products that aim to minimize these effects are advantageous to the culture. The use of 2,4-D herbicide, in low doses, can stimulate the development of the cotton crop by providing a hormesis effect. Therefore, the objective of the work will be to evaluate the vegetative, reproductive development and physiological analysis of cotton plants subjected to the use of subdoses of 2,4-D and a formulated compound of foliar stress reducers. The experiment will be conducted at Unesp, Dracena Campus. The experimental design will be in randomized blocks arranged in a 5x2 factorial scheme. The treatments will consist of the combination of five subdoses of the herbicide 2,4-D (0, 0.68, 2.04 and 3.40 and 4.76 g a.e. ha-1) applied via foliar in the cotton crop, at the stage B4 development, first floral bud on the fourth reproductive branch; and with or without use of the stress reducer, commercial product Recovery at a dose of 1.0 L ha-1, applied one day after the application of the subdoses, with 4 repetitions, totaling 40 installments. The plots will consist of 4 lines 6.0 m long, spaced 0.8 m apart (19.2 m2). Cotton sowing will be carried out mechanically in the second half of November 2024, FM 985 GLTP late cycle. Evaluations will be carried out on SPAD reading of chlorophyll, plant height, number of nodes, number of plants m-2, number of bolls per plant, average boll weight and cotton seed yield. The data will be subjected to analysis of variance and subsequently to polynomial regression analysis for the quantitative factor and Tukey's test for the qualitative factor at 5% probability.