كمي سازي وقوع تنش هاي دمايي در زراعت گندم (Triticum aestivum) در گرگان

Quantifying the occurrence of thermal stesses in wheat in Gorgan

Irrespective of technological advances in agriculture, still climate climat is the most important yield determinant factor. The objective of tjis study was to quantify to probability of occurrence of Thermal stresses at different growth stages of wheat at gorgan (the North of Iran) environmental conditions. To do this, first growth degree days requirment for different developmental stags were computed. Then, using 40 years daily weather data of Gorgan and a computer program, prepared for this study, the probability of occurrence of different stressfull temperatures for different processes (like emergence and Photosynthesis) were calculated. The results showed that wheat encounters low stressfull temperatures during emergence, photosynthesis during vegetative stage, stem elongation, flowering and pollination. However, high temperature occure during grain filling period that limit photosynthesis process. Results of this study can be used in cultural management and breeding of wheat and designing stTess physiology researches.