Search

Understanding the effects of warming trends, genetics, and management on crop phenology is crucial for adaptation against the increasing trend in temperature in the upcoming decades. The goal of this research was to quantify the impact of historic climate warming and management on sunflower phenology (stages and phases). In this project, spring and fall sunflower phenology and daily weather data were obtained for 20 locations in Punjab, Pakistan. We investigated the impact of thermal trend on the phenological stages and phase duration for spring and fall sunflower from 1980 to 2016. The results showed that the mean temperature increased by 0.9 and 0.8 °C decade −1 for spring and fall, respectively. The observed phenological stages such as sowing, emergence, anthesis, and maturity dates were earlier for spring by an average of 6.6, 6.3, 3.8, and 2.2 days decade -1 and delayed for fall by an average of 5.7, 5.4, 3.1, and 1.8 days decade -1 . The observed sowing to anthesis, anthesis to maturity, and sowing to maturity phases were reduced by an average of 2.8, 1.6 and 4.4 days decade -1 for spring and 2.5, 1.2, and 3.8 days decade -1 for fall. The changes in phenology of sunflower for spring and fall were highly correlated with the enhancement in warming trend during 1980–2016. The CSM-CROPGRO-Sunflower model using standard hybrids for all sites and years showed that the simulated phenology had accelerated due to the change in climate and the simulated phenological dates were earlier than the observed dates. These results indicate that earlier sowing dates for spring, delayed sowing dates for fall, and shifts of varieties that require elevated total growing degree days for the duration of 1980 to 2016 have somewhat mitigated the adverse impact of climate warming on spring- and fall-grown sunflower phenology for ensuring sustainable productivity and ensuring food security. [ABSTRACT FROM AUTHOR]

Crop production is greatly impacted by growing season duration, which is driven by prevailing environmental conditions (mainly temperature) and agronomic management practices (particularly changes in cultivars and shifts in sowing dates). It is imperative to evaluate the impact of climate change and crop husbandry practices on phenology to devise future management strategies to prepare for climate change. Historical changes in spring and autumn maize phenology were observed in Punjab, Pakistan during 1980–2014. Sowing (S) of spring maize was earlier by an average of 4.6 days decade −1 , while autumn maize ‘S’ and emergence (E) were delayed on average 3.0and 1.9 days decade −1 . Observed anthesis (A) plus maturity (M) dates were earlier by 7.1 and 9.2 days decade −1 and 2.8 and 4.4 days decade −1 for spring and autumn maize, respectively. Similarly, S-A, S-M and A-Mphases were shortened on average by 2.4, 4.6 and 1.9 days decade −1 and 5.5, 7.8 and 2.2 days decade −1 for spring and autumn maize, respectively. The variability in phenological phases of spring and autumn maize had significant correlation,with the increase in temperature during 1980–2014. Employing the CSM-CERES-Maize model using standard hybrid for all locations and years illustrated that model-predicted phenology has accelerated with climate change more than infield-observed phenology. These findings suggest that earlier late sowing and shifts of cultivars requiring high total growing degree day during 1980–2014, have partially mitigated the negative impact of climate change on phenology of both spring and autumn grown maize. [ABSTRACT FROM AUTHOR]