Desempenho agronômico e qualidade tecnológica de fibras de algodoeiro sob níveis de irrigação por gotejamento

Abstract

The objective of this work was to evaluate the performance of cotton cultivars under the effect of deficient irrigation, through an evaluation of growth, productivity and fiber quality in the northern region of Minas Gerais. For this, a field experiment was carried out in Janaúba - MG, involving five treatments of water replacement levels in the soil (RAS) via evapotranspirometric demand (T1 = 100; T2 = 85; T3 = 70; T4 = 55 and T5 = 40% of the ETc) and four cultivars (Delta Pine 1746 B2RF®; TMG 44 B2RF®; FM985 GLTp® and FM983 GLT®). The treatments were arranged in an experimental arrangement of subdivided plots for plant growth evaluations and subdivided for the evaluation of production and fiber technological quality, with replacements in the plots, the four cultivars in the subplots and evaluation times in the subsubplots in a design in randomized blocks, with 4 replications. For growth variables, irrigation levels below 85% of ETc reduce cotton growth. For growth variables, irrigation levels below 85% of ETc reduce cotton growth. For production variables, irrigation levels below 98.5% of ETc reduce seed cotton productivity and below 100% of ETc, reduce the yield of plumes of cotton cultivars. The cotton cultivars FM 985GLTP and FM 983GLT were the most productive of seed cotton. There was no difference between the cultivars for seed cotton productivity with the reduction of irrigation levels. For the technological quality of feathers, the replacement of 100% of ETc provided better technological quality of fibers. Irrigations with up to 85% of ETc guarantee a cotton plume yield of 1549.8 kg ha-1. The cultivars DP 1746B2RF and TMG 44B2RF had the highest fiber percentage, and the FM 983 GLT cultivar had the highest cotton lint yield. The fiber quality of cotton cultivars decreased as the percentage of water replacement via ETc decreased.