Meteorological conditions and their associations with the productive performance of wheat

Abstract

This study aimed at assessing the effect of the photothermal quotient, meteorological variables and their effects on the grain production and yield of the wheat cultivars in terms of hectoliter mass in Santa Maria, Rio Grande do Sul state, Brazil. The experiments were carried out in the same experimental area in different years. Four experiments were performed in the experimental field during the agricultural years of 2013 (10 cultivars), 2014 (16 cultivars), 2015 (15 cultivars) and 2016 (15 cultivars) with the principal cultivars in the Rio Grande do Sul state, during each of these years. The meteorological factors (mean air temperature, solar radiation, insolation and accumulated precipitation) showed wide fluctuations over these years. They induced instability in the production. The grain yield and the hectoliter mass were compared in each of the agricultural years (Scott-Knott, α≤0.05) and are related in dispersion plots according to the climatic variables for the set of years and cultivars (regression analysis). The available solar radiation (number of sunshine hours), quality (photothermal quotient) and average air temperature were the determinant factors for wheat productivity. However, the hectoliter mass was influenced more by the effect of genetic variability, lack of precipitation during crop maturation, and photothermal quotient around the time of anthesis. Wheat crop investments can be expanded to maximize wheat grain yield when average cycle temperatures remain near 16.5 oC, high solar radiation and low rainfall. Better quality trains (hectoliter mass) will be obtained when smaller precipitations are observed at harvest and higher photothermal quotient.