INTERNATIONAL JOURNAL OF AGRICULTURE & BIOLOGY ISSN Print: 1560–8530; ISSN Online: 1814–9596 12–055/MFA/2012/14–3–407–412 http://www.fspublishers.org Full Length Article To cite this paper: Ahmed, M., F.U. Hassan, M. Aslam and M.A. Aslam, 2012. Physiological attributes based resilience of wheat to climate change. Int. J. Agric. Biol., 14: 407–412 Physiological Attributes Based Resilience of Wheat to Climate Change MUKHTAR AHMED 1 , FAYYAZ-UL-HASSAN, M. ASLAM† AND M.A. ASLAM Department of Agronomy, PMAS-Arid Agriculture University Rawalpindi, Pakistan †Commissioner for Minor Crops, Ministry of Food and Agriculture, Islamabad, Pakistan 1 Corresponding author’s e-mail: ahmadmukhtar@uaar.edu.pk ABSTRACT Climate change may affect wheat positively or negatively when global warming is likely to increase evapotranspiration (ET) and decrease crop physiological functions. More often droughts are being encountered in Pothwar because of high ET and low precipitation in the form of rainfall. The impact of climate change on physiological attributes [Net photosynthesis(An), stomatal conductance(gs) and transpiration (E)] of spring wheat in Pothwar was studied through field experiments conducted at National Agriculture Research Centre (NARC), Islamabad, Barani Agriculture Research Institute (BARI), Chakwal and at farmer’s field Talagang over two years (2008-2009 & 2009-2010). The treatments consisted of five planting windows, three genotypes arranged in Randomized Complete Block Design (RCBD) factorial replicated four times. The results revealed that changing environment and sowing dates changed the adaptability pattern of wheat crop at three locations, because of change in the temperature and rainfall over the phenological stages of wheat. The reduction in net photosynthetic rate during 2009- 2010 was 21% compared to 2008-2009, while among locations 20% decrease in An was recorded at Talagang from maximum value at Islamabad. The gs dropped to 50% during 2009-2010 due to temperature and moisture stress, while 92% reduction in gs was recorded at Talagang compared to highest value. However, transpiration rate dropped to 71% during 2009-2010, while among locations crop showed minimum transpiration (79% less than maximum) at Talagang. At Chakwal significant decrease in crop physiological parameters declined the grain yield. Talagang being the low rainfall and relatively higher temperature area of Pothwar produced the lowest yield due to drop in physiological functions of crop and reduced LAD and LAI. Findings of the present study provided support for further physiological investigations and potential strategy for minimizing the climate risk especially in rainfed agriculture. © 2012 Friends Science Publishers Key Words: Climate change; Net photosynthesis; Transpiration; Leaf area duration; Yield INTRODUCTION Weather and climate are the key factors affecting the agricultural productivity. Being open to vagaries of nature, agriculture sector is highly vulnerable to climate change phenomena. Change in water availability to crops may be attributed to annual rise of 0.3°C in world average temperature, which would lead to limit cereal production (Schneider, 2007). The physiological processes including alleviation of photosynthetic efficiency, oxidative damage, uptake of water and nutrients by crop are severely affected under continuously changing temperature and moisture disparity (Wang et al., 2011). Similarly, climate change in the form of temperature rise and rainfall variability in many parts of world caused countries cereal grain yield stagnation and increased yield variability (Olesen et al., 2011). Hence, plant growth and productivity is severely affected by nature in the form of biotic and abiotic stresses like water stress therefore, physiological and morphological changes in plants needs to be addressed as mitigation approach (Jaleel et al., 2009). Stresses (water & temperature) due to climate change reduce crop growth by affecting various physiological and biochemical processes such as photosynthesis, respiration, translocation and nutrient metabolism (Jaleel et al., 2008a‒b; Farooq et al., 2008, 2009a‒c, 2011). Meanwhile, Makino (2011) discussed the importance of photosynthesis and depicted that photosynthetic efficiency constituent 90% in total dry matter accumulation. Thus, an increase in photosynthetic efficiency of crops led to enhanced photoassimilate and ultimately higher yield. Similarly, Long et al. (2006) estimated strong relationship among physiological indices and grain yield. They reported an increase in yield with increase in physiological attributes. Plant physiological processes found to be strongly influenced under continuous varying climatic scenarios as increase in temperature and moisture depletion led to reduced photosynthetic efficiency and consequently limited yield of crop (Athar & Ashraf, 2009). Exposure to temperature stress (heat) found to be a limiting factor for grain yield of wheat crop (Parya et al., 2010). In general the