Affiliation:
1. Universidade Federal de Santa Maria, Brazil
Abstract
Abstract Dahlia is an ornamental plant well adapted to open field cultivation and is one of the crops in the “Flowers for All” Project, a nation-wide extension project. High temperatures and the duration of extreme heat waves are expected to be more frequent in the next decades. Therefore, understanding and determining the high temperature that causes irreversible damage in Dahlia flowers is of high interest for preparing farmers to mitigate and adapt their crop to climate change. The objective of this study was to determine the upper lethal temperature that causes irreversible damage on buds and flowers on open field grown dahlia. Commercial open field dahlia crops in five locations in Rio Grande do Sul (RS) State, Southern Brazil, during two growing seasons (2021/22 and 2022/23) were used in this study. During the period from 20 December 2021 to 30 January 2022 and from 14 January 2023 to 20 January 2023, daily observations were made in the dahlias in the five locations in order to identify symptoms of heat stress on leaves, buds and flowers such as leaf rolling, wilting, dry leaf edges, sunscald, burning and rotting. The appearance of those symptoms was correlated with maximum daily air temperature in order to estimate the lethal temperature. Irreversible heat injury in buds and flowers of open field grown dahlia start when air temperature reaches 35 oC. Artificial shading, irrigation and planting date are management practices that can help farmers to protect dahlia flowers from heat stress.
Subject
Horticulture,Plant Science
Reference21 articles.
1. Assessing climate change effects on gladiola in Southern Brazil;BECKER C.C.;Scientia Agricola,2021
2. Fenologia: ferramenta para conservação, melhoramento e manejo de recursos vegetais arbóreos;BERGAMASCHI H.,2007
3. Irrigation scheduling based on crop canopy temperature for humid environments;BOCKHOLD D.L.;Transactions of the ASABE,2011
4. Modeling temperature and photoperiod effects on growth and development of Dahlia;BRONDUM J.J.;Journal of the American Society Horticultural Science,1993
5. Condições meteorológicas ocorridas em janeiro de 2022 e situação das principais culturas agrícolas no estado do Rio Grande do Sul;CARDOSO L.S.;Comunicado Agrometeorológico,2022