Phenological Temperature Response of Maize

Abstract

Variability of development rate estimates across locations and years using the current heat unit system of growing degree‐days (GDD) with maximum and minimum temperature thresholds of 30 and 10°C (GDD30,10) limits predictability of maturity in hybrid maize (Zea mays L.). Data sets of daily maximum and minimum air temperatures and dates of maize development stages were collected for a range of hybrids at locations in Canada and the northern USA (39° to 45° N lat). Data were analyzed to improve the temperature response functions for maize at different stages of development. Results indicate that during vegetative growth, phenological response to mean daily air temperature followed a sigmoidal curve beginning below 5°C, with maximum response to temperatures between 25 and 30°C. During reproductive growth, the temperature response function was flat from 0 to 12°C and rose significantly only with mean daily air temperatures greater than this range. A general thermal index (GTI) based on these two response functions improved estimation of maturity dates by 50% over estimates made using GDD30,10 (SE of 6.7 d for GTI and 13.6 d for GDD30,10 in estimating time from planting to maturity). The greatest improvement using GTI occurred for the reproductive period (SE of 5.8 d using GTI, compared with 12.1 d using GDD30,10). These results suggest that incorporating the temperature response function reported in this paper would improve prediction of maize development.

Phyllochron responds to acclimation to temperature and irradiance in maize

“…We have used the mean temperature prior to a specific phenological event (tassel initiation) as the criterion, rather than for a nominated thermal interval (200 o Cd, base temperature for wheat and barley = 0 o C) from emergence used by Kirby (1995). In calculating thermal time, and thus phyllochron, we used the widely accepted base temperature of 8 o C in both maize and sorghum, despite reports of base temperatures ranging from 6 to 10 o C (e. 16 g. Warrington and Kanemasu 1983, Hesketh and Warrington 1989, Stewart et al 1998). Use of a lower or higher base temperature from the range of 6 to 10 o C did not change the form of the relationship reported in this study, so we retained the base temperature of 8 o C for all experiments.…”

A re-evaluation of crop heat units in the maritime provinces of Canada

“…However, reasons have not been substantiated by published research up to now. Differences in thermal requirements could not be eliminated by using a General Thermal Index (Stewart et al 1998) that uses a different temperature response for the vegetative and reproductive periods, nor by using CHU calculated from hourly temperature data (Bootsma unpublished data). The CHU map in Fig.…”

Integración del Índice de Vegetación de la Diferencia Normalizada (NDVI) y del Ciclo Fenológico de Maíz para Estimar el Rendimiento a Escala Departamental en Córdoba, Argentina

“…Estas técnicas determinan en forma simple el momento de ocurrencia de un evento fenológico a partir de información tér-mica, superando la mayor inexactitud que deriva de usar los días calendarios de manera directa (Warrington y Kanemasu, 1983; Kiniry y Bonhomme, 1991; Stewart et al, 1998). Esta información es relevante porque las etapas de desarrollo de los cultivos presentan condiciones de sensibilidad particular frente al estrés hídrico.…”