Efeito da desfolha artificial do algodão (Gossypium hirsutum L.), em diferentes estádios fenológicos, cultivada no sistema adensado e convencional

Abstract

Studies on artificial defoliation are very useful, especially to simulate damage to plants, such as those caused by insects and diseases. The ability of cotton plants to recover after defoliation usually varies depending on the level of defoliation, time of development that is subject to damage and cropping system. The aim of this study was to analyze the behavior of cotton on different levels of defoliation, seeking a better economic management culture in the narrow and conventional cropping system. The experiment was conducted under field conditions in Dourados - MS using the cultivar NUOPAL RR® in a randomized block design with split plots and four repetitions in two cropping systems. The treatments consisted of five phases of crop development: [V3 (first leaf), B1 (first flower buds), F1 (opening of the first flower on the 1st branch) F5 (opening of the first flower on the 5th branch) and C1 (first bolls)]-four defoliation levels (0%, 33%, 66% and 99%). The effect of defoliation on variable-rate responses of productivity, phenology and quality of fiber is dependent on the phenological stage of plant development. The greatest losses occur at the phenological stage F1, both in quantity and quality of fiber. The reduced leaf area in the stadium C1 does not generate significant losses in cotton production.