Inter-relação entre diferentes doses de potássio e nitrogênio e genes Bt sob a produtividade de milho

Abstract

The corn crop exhibits great social and economic importance worldwide, as it is one of the main agricultural species, thus, new alternatives and technologies have been studied to improve productivity and environmental conditions. These technologies include the use of nitrogen and potassium fertilization and cultivars containing Bt genes. The use of biotechnology helps in the development of genes that codify proteins with insecticidal activity and help in the integrated management of pests, while fertilization exhibits a function of improving plant development and increases in nutritional levels. The objective of the work was to identify the effect of potassium and nitrogen doses on Bt transgenic resistance, based on the damage caused in maize hybrids. The experiments were carried out at the State University of Goiás, located in the municipality of Ipameri, in the 2014/15 and 2015/16 summer harvests. In the potassium experiment, a randomized block design was used, in a factorial arrangement (3 x 6), three doses of potassium (0, 45 and 90 kg ha-1) and six corn hybrids [A. (20A55Hx); B. (30A77PW); C. (AG1051); D. (MG652PW); E. (NS90VTPro2) and F. (NS92VTPro)], with three replications. In the nitrogen experiment, a randomized block design was used, in a factorial arrangement (3 x 6), three nitrogen rates (0, 80 and 160 kg ha-1) and with the same six corn hybrids, with three replications. The use of different doses of nitrogen and potassium showed no interference in the hybrids against the attack of Spodoptera frugiperda caterpillars. The hybrids that expressed the proteins Cry1A.105 and Cry2Ab2 in a combined way, allied or not to the protein Cry1F, obtained better performance in the control of caterpillars, however the isolated protein Cry1F did not provide effective control.