Resposta de cultivares de trigo ao nitrogênio com e sem tratamento fúngico

Abstract

A aplicação de fungicida pode garantir maior resposta à adubação nitrogenada, visto que a aplicação de doses mais elevadas de N podem propiciar melhores condições para o desenvolvimento de algumas doenças. O objetivo deste trabalho foi avaliar os efeitos de diferentes doses de N e da aplicação de fungicida em caráter preventivo na produtividade de dois cultivares de trigo, irrigado em condições de cerrado. O experimento foi realizado em Selvíria, MS, em um Latossolo Vermelho Distrófico. Os tratamentos foram arranjados em um delineamento de blocos ao acaso, em um esquema fatorial 4x2x2, ou seja, quatro doses de N (0, 60, 120 e 180 kg ha -1 ) em cobertura no início do emborrachamento, na forma de ureia em dois cultivares de trigo (IAC 24 e IAC 370) com e sem aplicação de fungicidas (Tebuconazole e Triciclazol) com quatro repetições. Os cultivares IAC 24 e IAC 370 apresentam produtividades de grãos semelhantes. O aumento das doses de N influencia negativamente a massa hectolítrica e positivamente o teor foliar de N e número de espigas por m 2 . O incremento das doses de N aumenta a produtividade de grãos de trigo até a dose de 116 kg ha -1 de N, independentemente do cultivar e da aplicação ou não de fungicida preventivamente, devido à não ocorrência de doenças.Palavras-chave: cerrado, irrigação por aspersão, produtividade de grãos, Triticum aestivum L., ureia Response of wheat cultivars to nitrogen with and without fungal treatment ABSTRACTThe fungicide can enhance response of nitrogen fertilization on wheat crop, since the application of higher N rates can provide better conditions for the development of some diseases. The present study investigated the effects of different nitrogen doses and fungicide application in preventive character on the yield of two cultivars of wheat irrigated, in Savannah conditions. The experiment was conducted in Selvíria -MS, in a Distrophic Red Latosol (Typic Haplustox). Treatments were arranged in a randomized block design, in a 4x2x2 factorial scheme: four N rates (0, 60, 120 and 180 kg ha -1 ), topdressing at the early boot stage as urea, two wheat cultivars (IAC 24 and IAC 370), and with and without fungicide application (Tebuconazole and Triciclazol), with four replications. The cultivars IAC 24 and IAC 370 present similar grain yield. The increase of N doses influences the mass hectoliter negatively and the leaf N content and number of ears per m 2 positively. The increment of N doses increase the grain yield up to dose of 116 kg ha -1 of N, regardless of cultivar and of the fungicide application in preventive character, due to non occurrence of diseases in the experiment.

Performance of white oat cultivars in response to nitrogen fertilization and trinexapac-ethyl

“…Theago et al (2014) obtained a quadratic response of the N level on plant height, with a maximum point at 148 kg N ha -1 . In contrast, Prando et al (2013) and Teixeira Filho et al (2012) showed that N topdressing did not influence plant height. The different responses of cultivars in plant height, depending on the application of the plant growth regulator, are related to the recommended level of trinexapac-ethyl (100 to 125 g i.a.…”

“…Theago et al (2014) obtained a quadratic response of the N level on plant height, with a maximum point at 148 kg N ha -1 . In contrast, Prando et al (2013) and Teixeira Filho et al (2012) showed that N topdressing did not influence plant height. According to Marschner (1995), the application of high levels of N in cereals increases the production of phytohormones, plant growth, and development promoters responsible for the processes of cell division and expansion, increasing stem elongation and, consequently, plant height.…”

“…Table 4 shows that the lowest number of grains per panicle was obtained with the cultivar IPR Artemis. Several studies have been carried out in different cultivars of wheat and rice crops by evaluating the use of plant growth regulators and N application level and also showed a significant effect of plant genotype on the number of grains per panicle (ARF et al, 2012;SCHWERZ et al, 2015;TEIXEIRA FILHO et al, 2012.…”

Do the application forms and doses of boron affect wheat crops?

“…Wheat (Triticum aestivum L.) is an annual cycle plant and a type of cool-season cereal. Wheat has great economic importance and large grain yield capacity (Teixeira Filho et al, 2010, 2012Marini et al, 2011;Theago et al, 2014). This cereal occupies over 17% of cultivable land in the world and represents approximately 30% of world grain production.…”

Technical and Economic Viability of Wheat with Forms of Application and Doses of Boron

“…Wheat (Triticum aestivum L.) is an annual cycle plant, considered among the cool season cereal, one that has greater economic importance, with large grain yield capacity (Teixeira Filho et al, 2010;Marini et al, 2011;Teixeira Filho et al, 2012Theago et al, 2014). The cereal occupies over 17% of cultivable land in the world and represents approximately 30% of world grain production.…”