Modelagem do desenvolvimento de trigo considerando diferentes temperaturas cardinais e métodos de cálculo da função de resposta à temperatura

Abstract

Resumo -O objetivo deste trabalho foi melhorar a estimativa dos estádios de desenvolvimento de genótipos brasileiros de trigo (Triticum aestivum) realizada por meio do modelo WE-Streck. Foram avaliadas diferentes combinações de temperaturas cardinais e métodos de cálculo da função de resposta à temperatura. Dados referentes às datas da emergência, da emissão da espigueta terminal, da antese e da maturidade fisiológica de seis genótipos brasileiros de trigo semeados em 11 datas ao longo de três anos (2005, 2006 e 2007) em Santa Maria, RS, foram usados para estimar os coeficientes do modelo WE-Streck modificado e testar as diferentes combinações de temperaturas cardinais e métodos de cálculo da função de resposta à temperatura. Para os genótipos BRS Louro, BRS 177, CEP 51, CEP 52 e Nova Era, a simulação do desenvolvimento com o modelo de WE-Streck é melhor quando são usados maiores valores de temperaturas cardinais ótima e máxima, em comparação às usadas originalmente no modelo. Para o genótipo BRS Tarumã, devem ser utilizadas as temperaturas cardinais do modelo WE-Streck original. É recomendável usar as temperaturas mínimas e máximas diárias para calcular a função de resposta à temperatura quando o modelo WE-Streck for usado para simulação do desenvolvimento de genótipos brasileiros de trigo.Termos para indexação: Triticum aestivum, fenologia, simulação do desenvolvimento. Modeling wheat development considering different cardinal temperatures and methods for the temperature response function calculationAbstract -The objective of this work was to improve the prediction of developmental stages of Brazilian wheat (Triticum aestivum) genotypes made using the WE-Streck model. Different combinations of cardinal temperatures and methods of calculating the temperature response function were evaluated. Data regarding the dates of emergence, terminal spikelet, anthesis, and physiological maturity of six Brazilian wheat genotypes sown on 11 dates during three years (2005, 2006, and 2007) at Santa Maria, RS, Brazil, were used to estimate the WE-Streck model coefficients and to evaluate the different combinations of cardinal temperatures and methods for calculating the temperature response function. For the genotypes BRS Louro, BRS 177, CEP 51, CEP 52, and Nova Era, the simulation of the development with the WE-Streck model is better with higher values of optimum and maximum cardinal temperatures compared to those originally used in the model. For the genotype BRS Tarumã, the cardinal temperatures from the original version of the WE-Streck model should be used. It is recommended that the minimum and maximum daily temperatures be used to calculate the temperature response function when the WE-Streck model is selected for simulating the development of Brazilian wheat genotypes.

Simulation of oat development cycle by photoperiod and temperature

“…The simulated results are similar to those found in wheat by Alberto et al (2009), who obtained estimated values varying from 1.2 to 7.3 days for the stage from maturation to terminal spikelet, from 3.5 to 8.1 days for the stage from terminal spikelet to anthesis and from 6.3 to 12 days for the stage from anthesis to maturation, as well as Streck et al (2003), who studied winter wheat and found that the estimates of the stages varied from 3 to 8 days.…”

“…This study with oat used the coefficients of r max,v and r max,r developed for wheat cultivars by Streck et al (2003) and Alberto et al (2009), according to Table 1.…”

“…However, the thermal oscillations in the cultivation years and the photoperiod may modify the duration of the development of this species (Castro et al, 2012;Leite et al, 2012). Table 4 presents the coefficients of wheat development obtained by Streck et al (2003) and Alberto et al (2009) that best adjusted to the oat development stages, in the different combinations of temperature and days of simulated development. Each combination of temperature (T1, T2, T3, T4, T5 and T6) resulted in a different number of days of simulated development.…”

“…Streck et al (2003) modified the WE model by dividing the vegetative cycle of wheat into two subphases (emergence to terminal spikelet; terminal spikelet to anthesis) and the reproductive cycle into one phase (anthesis to maturation), through combinations of cardinal temperatures. According to Alberto et al (2009), these modifications improved the simulation of wheat development stages, and the model was called WE-Streck. These authors used the WE-Streck model to simulate new coefficients of development in Brazilian wheats.…”

“…Nitrogen, for being the most required nutrient, also modifies the duration of the oat development stages (Flores et al, 2012;Pietro-Souza et al, 2013). Since wheat and oat are similar species regarding the development cycle (Baier et al, 1988), the coefficients estimated for wheat by Streck et al (2003) and Alberto et al (2009) in the WE-Streck model can be employed in the simulation of the oat development cycle under conditions of N application.…”