The effect of high temperature stress on six wheat cultivars exposed to 35-40 °C for 3 h each day for five consecutive days was examined. High temperature significantly affected total proline, soluble protein content, membrane stability index (MSI), yield, and various yield components, and had a direct effect on growth and other physiological attributes of wheat at anthesis and the milky seed stages. The wheat cultivar AS- 2002 achieved better osmotic adjustment by accumulating more leaf proline. Higher MSI was also observed in AS-2002, as well as Inqalab-91. The anthesis growth stage was found to be more sensitive to heat stress than seed development at the milky stage. Overall heat stress reduced yield 75% at anthesis and 40% at the milky stage. AS-2002 performed better on the basis of yield and yield components. Seed weight per spike was highest in AS- 2002, and lowest in SH-2002. The cumulative response of AS-2002 was better on the basis of physiological and yield attributes. In addition to yield, plant breeders should also include proline and MSI as selection parameter in the breeding program for development of heat tolerant wheat cultivars. Most of the evaluated wheat cultivars/lines were developed for cultivation in the rainfed areas of Pakistan.
AHMED, J. U., HASSAN, M. A., 2011: Evaluation of seedling proline content of wheat genotypes in relation to heat tolerance. Bangladesh Journal of Botany 40, 17-22.
ASHRAF, M., FOOLAD, M. R., 2007: Roles of glycine betaine and proline in improving plant abiotic stress resistance. Environmental and Experimental Botany 59, 206-216.
BALOUCHI, H. R., 2011: Screening wheat parents of mapping population for heat and drought tolerance, detection of wheat genetic variation. International Journal of Biological and life Sciences 7, 56-66.
BATES, L. S., WALDERN, R., TEARE, I. D., 1973: Rapid determination of free proline for water stressed studies. Plant and Soil 39, 205-207.
BLUM, A., KLUEVA, N., NGUYEN, H. T., 2001: Wheat cellular thermotolerance is related to yield under heat stress. Euphytica 117, 117-123.
BRADFORD, M. M., 1976: Rapid and sensitive method for quantitation of microgram quantities of protein utilizing the principle of protein dye binding. Analytical Biochemistry 72, 248-254.
DHANDA, S. S., MUNJAL, R., 2006: Inheritance of cellular thermotolerance in bread wheat. Plant Breeding 125, 557-564.
DIN, R., SUBHANI, G., AHMAD, N., HUSSAIN, M., RHMAN, A., 2010: Effect of temperature on development and grain formation in spring wheat. Pakistan Journal of Botany 42, 899-906.
DIN, J., KHAN, S. U., ALI, I., GURMANI, A. R., 2011: Physiological and agronomic response of canola varieties to drought stress. Journal of Animal and Plant Sciences 21, 79-83.
FERRIS, R., ELLIS, R. H., WHEELER, T. R., HADLEY, P., 1998: Effect of high temperature stress at anthesis on grain yield and biomass of field-grown crops of wheat. Annals of Botany 82, 631-639.
FOOLAD, M. R., 2005: Breeding for abiotic stress tolerances in tomato. In: Ashraf, M., Harris, P. J. C., (eds.), Abiotic stresses; Plant resistance through breeding and molecular approaches, 613-684. The Haworth Press Inc., New York (USA).
GIBSON, L. R., PAULSEN, G. M., 1999: Yield components of wheat grown under high temperature stress during reproductive growth. Crop Science 39, 1841-1846.
GUPTA, A. K., KAUR, K., KAUR, N., 2011: Stem reserve mobilization and sink activity in wheat under drought conditions. American Journal of Plant Sciences 2, 70-77.
HASAN, M. A., AHMED, J. U., BAHADUR, M. M., HAQUE, M. M., SIKDER, S., 2007: Effect of late planting heat stress on membrane thermostability, proline content and heat suscepti bility index of different wheat cultivars. Journal of the National Science Foundation of Sri Lanka 35, 109-117.
HE, Y., LIU, X., HUANG, B., 2005: Protein changes in response to heat stress in acclimated and non acclimated creeping bent grass. Journal of the American Society for Horticultural Science 130, 521-526.
HONG, Z., LAKKINENI, K., ZHANG, Z., VERMA, D. P. S., 2000: Removal of feedback inhibition of D 1-pyrroline-5-carboxylate synthetase results in increased proline accumulation and protection of plants from osmotic stress. Plant Physiology 122, 1129-1136
KHAN, M. A., HUSSAIN, M., 2006: A. S. 2002, a new high yielding, disease resistant and heat tolerant wheat variety. Pakistan Journal of Agricultural Research 19, 16-22.
KHAN, M. I., MOHAMMAD, T., SUBHAN, F., AMINE, M., SHAH, S. T., 2007: Agronomic evaluation of different bread wheat (Triticum aestivum L.) genotypes for terminal heat stress. Pakistan Journal of Botany 39, 2415-2425.
LAGHARI, K. A., SIAL, M. A., ARAIN, M. A., 2012: Effect of high temperature stress on grain yield and yield components of wheat (Triticum aestivum L.). Journal of Science, Technology and Development 31, 83-90.
MOHAMMADI, M., KARIMZADDEH, R. A., NAGHAVI, M. R., 2009: Selection of bread wheat genotypes against heat and drought tolerance based on chlorophyll content and stems reserves. Journal of Agriculture and Social Sciences 5, 119-122.
NAHAR, K., AHMAD, K. U., FUGITA, M., 2010: Phenological variation and its relation with yield in several wheat (Triticum aestivum L.) cultivars under normal and late sowing mediated heat stress condition. Notulae Scientia Biologicae 2, 51-56.
PARENT, B., TURC, O., GIBON, Y., STITT, M., TARDIEU, F., 2010: Modeling temperature-compensated physiological rates, based on the coordination of responses to temperature of developmental processes. Journal of Experimental Botany 61, 2057-2069.
PORTER, J. R., 2005: Rising temperatures are likely to reduce crop yields. Nature 436, 174.
RONDE, J., MESCHT, A., STEYN, H. S. F., 2001: Proline accumulation in response to drought and heat stress in cotton. African Crop Science Journal 8, 85-91.
SAIRAM, R. K., RAO, K. V., SRIVASTAVA, G. C., 2002: Differential response of wheat genotypes to term salinity stress in relation to oxidative stress, antioxidant activity and osmolyte concentration. Plant Science 163, 1037-46.
SIKDER, S., AHMED, J. U., HOSSAIN, T., 2001: Heat tolerance and relative yield performance of wheat varieties under late seeded conditions. Indian Journal of Agricultural Research 35, 141-148.
SIMMONDS N. W., 1995: The relation between yield and protein in cereal grain. Journal of the Science of Food and Agriculture 67, 309-315.
SNEDECOR, G. W., COCHRAN, W. G., 1980: Statistical methods. 7th Edition, Iowa State University Press, Ames, Iowa.
VERSLUES, P. E., SHARMA, S., 2010: Plant-environment interaction: proline metabolism and its implications for plant-environment interaction. Plant Physiology 157, 292-304.
WAHID, A., GELANI, S., ASHRAF, M., FOOLAD, M. R., 2007: Heat tolerance in plants: an overview. Environmental and Experimental Botany 61, 199-223. WAHID, A., CLOSE, T. J., 2007: Expression of dehydrins under heat stress and their relationship with water relations of sugarcane leaves. Biology of Plants 51, 104-109.
WARDLAW, I. F., 2002: Interaction between drought and chronic high temperature during kernel filling in wheat in a controlled environment. Annals of Botany 90, 469-476.
WEI-TAO, L., LIN, B., ZHANG, M., HUA, X. J., 2011: Proline accumulation is inhibitory to Arabidopsis seedlings during heat stress. Plant Physiology 156, 1921-1933.
YILDIRIM, M., BAHAR, B., KOC, M., BARUTCULAR, C., 2009: Membrane thermal stability at different developmental stages of spring wheat genotypes and their diallel cross populations. Tarim Bilimleri Dergisi 15, 293-300.
YOU, L., ROSEGRANT, M. W., WOOD, S., SUN, D., 2009: Impact of growing season temperature on wheat productivity in China. Agricultural and Forest Meteorology 149, 1009-1014.