Study of Terminal Heat Stress Effect in Yield and Yield Attributing Characters of Wheat: A Review
Authors: Asha Thapa, Sushil Jaisi, Mukti Ram Poudel
Number of views: 137
Wheat is an important staple food of world. Terminal heat stress is a major factor limiting wheat production in world. Reproductive stage of wheat is very sensitive to terminal heat stress. High temperature reduces days to booting, days to heading, days to anthesis, days to maturity, chlorophyll content, plant height, thousand kernel weight, spike per m2, number of spikelets per spike, spike length, spike weight, number of grains per spike and grain yield. Heat stress causes alternation in physiological, biochemical and molecular level of wheat plant. Photosynthesis is most effecting physiological process. High temperature causes disruption of thylakoid membranes and disintegration of photosynthetic pigments resulting poor photosynthetic activity. In heat stress condition ROS (Reactive Oxygen Species) is produced which is very reactive and toxic that causes damages to cells. Plant produces detoxifying enzymes and antioxidants to detoxify effect of ROS. Osmotic pressure of cell is altered during heat stress condition which is balanced by producing proline and sugars in cells. EF-Tu (elongation factor thermo unstable), sRNA (small RNA), Hsp (Heat shock protein), Hsf (Heat shock factor), protein kinase acts as responsible factor to control heat stress in molecular level.