Nitrogen and trinexapac-ethyl effects on wheat grain yield, lodging and seed physiological quality in southern Brazil

Abstract

Summary Nitrogen (N) fertilization affects wheat yield and grain protein concentration; however, its mismanagement can increase plant lodging. While the use of plant growth regulators such as trinexapac-ethyl (TE) can mitigate plant lodging, their effects on seed physiological quality are not well known. The aim of this study was to evaluate the effects of N fertilization and TE on wheat yield, lodging and seed quality of spring wheat varieties. It was carried out in the 2018 growing season in the environments of Londrina and Ponta Grossa, Brazil. A randomized complete block design was used with a 2 × 3 × 3 factorial arrangement to evaluate two wheat genotypes (WT 15008 and WT 15025), three top-dressing N rates (0, 40 and 120 kg ha−1), and three TE rates (0, 50 and 100 g ha−1). Agronomic characteristics related to wheat productivity (hectolitre weight, thousand-grain weight, density of fertile spikes, plant height, lodging and grain yield) and seed physiological quality (seed germination and vigour; length and dry matter of normal seedlings) were evaluated. Increasing N rates up to 120 kg ha−1 increased plant lodging up to 26.4 percentage points for WT 15025 in Londrina. TE impaired some traits of seed physiological quality. Spraying 100 g ha−1 TE on the plants reduced seedling length by 9.4% in the seeds of WT 15008 harvested in Ponta Grossa compared to the TE control (0 g ha−1). The dry matter of the seedlings from the seeds harvested in Londrina declined by 7.2% due to the application of 100 g ha−1 TE, compared to the control. However, a lower rate of TE (50 g ha−1) might be enough to minimize plant lodging without impairing the physiological quality of the seeds, depending on the rate of N fertilization. This study is the first step in providing empirical evidence for the detrimental effects of TE in combination with N on wheat seed quality, suggesting that seed producers should exercise caution in managing TE and N fertilization.

Technological quality of wheat grains and flour as affected by nitrogen fertilization and weather condition

“…On the other hand, Yong et al (2004) verified that the falling number was mainly influenced by environmental factors, considering 39 wheat genotypes cultivated in four agroecological zones from China. Therefore, both factors -genotype and environmental conditions -can change the falling number, in addition to influencing other technological quality parameters of wheat flour and grain (Rozbicki et al, 2015;Souza et al, 2021;Faria et al, 2022;Martins et al, 2023), as observed in the present paper.…”

“…The aforementioned technological quality traits are defined by wheat genotype, environment, and the genotype × environment interaction, including soil and climate conditions, in addition to being influenced by crop management practices (e.g. fertilization, irrigation, plant growth regulators usage, and control of pests and diseases), harvest process, and drying and storage operations (Blumenthal et al, 1993;Guarienti et al, 2004;Yong et al, 2004;Franceschi et al, 2009;Denčić et al, 2011;Kaya and Akcura, 2014;Rozbicki et al, 2015;Ferreira et al, 2021;Rekowski et al, 2021;Faria et al, 2022). In this context, the supply of essential mineral nutrients by fertilizers is fundamental for the suitable growth and development of wheat plants, favoring the yield and quality of wheat grains and flour (Xue et al, 2016;Ma et al, 2019;Guerrini et al, 2020).…”

Intensive management simultaneously reduces yield gaps and improves milling and baking properties of bread wheat

“…Thus, in the high‐input treatment, the synergistic effect of N fertilization, S application, and foliar fungicides may have contributed to positive correlation between yield and GP, which is supported by preliminary evidence where M maintained or improved wheat grain quality (Torrion & Stougaard, 2017; Zecevic et al., 2010). Grain protein is directly influenced by nitrogen management (Daaloul Bouacha et al., 2014; Lollato et al., 2019b, 2021; de Faria et al., 2022; Vazquez et al., 2019), and increased levels of nitrogen available usually increase wheat GP (Mohammed et al., 2013) and wet gluten content (Zecevic et al., 2010). Generally, increases in GP are associated with increases in ω gliadins and high‐molecular‐weight GS but a decrease in α‐, γ‐gliadins and low‐molecular‐weight GS.…”