EFICIÊNCIA DE USO DO NITROGÊNIO POR HIBRIDOS DE MILHO DE ALTO POTENCIAL PRODUTIVO

Abstract

Corn is a very important crop in agricultural marketplace in Brazil. That is why planted area has been increasing, and many plant breeding companies has been investing every year more money to develop new hybrids that have great productive potential. Other relevant think is nitrogen use to improve yield. This experiment was carried out to identify vegetative indices that correlate with nitrogen use efficiency, as well as to assist in the hybrids differentiation and classify them according to responsiveness and efficiency regarding nitrogen use. Dekalb (DKB290, DKB310, DKB3700, DKB320); Pionner (P3646, P30F53); DOW (DAS610); Morgan (MG580); Agroeste (AS1633) and Agroceres (AG8700) hybrids, that represent different crop cycles between then, were evaluated using 2 rates of nitrogen, level 1 with 54 kg.ha-1 and level 2 with 153 kg.ha-1. The test was conducted in the Rio Verde city, in the Goiás state, in a clayey Red Latosol type soil. Quantitative evaluations were made in relation to agronomic characteristics related and sensors were used to evaluate index like SPAD and chlorophyll quantity on the aerial plant leaves, some sensors were shipped on drones to verify if there is correlation of vegetative index with the N efficiency. Those evaluations demonstrated that modern hybrids use nitrogen with different effectiveness. The DKB3700 and DKB290 hybrids were more efficient according to the Tukey test at 5% significance. The 10 hybrids tested were classified according to their responsiveness and efficiency regarding the nitrogen use. Among the evaluations made, there was a correlation between EUN and difference between the hybrids productivity in the different N doses, as well as a correlation between SPAD index, chlorophyll content and vegetative index D678 / 500 was observed.