INDUCING THERMO-TOLERANCE IN LATE SOWN WHEAT (Triticum aestivum L.) THROUGH PRE-CONDITIONING WITH H2O2.

Late sown wheat covers 56% of total cultivated area of wheat in Pakistan which makes it vulnerable to sub and supra optimal temperatures. Although there is no substitutes to timely sowing, techniques are available that could mitigate the harmful effects of late sowing. Therefore; a field study was conducted to evaluate the role of H2O2 in mitigation of negative effects of high temperature at reproductive phase, during 2011-12 and 2012-13. Treatments comprised of two sowing dates (20th Nov and 20th Dec) and foliar application of H2O2 (75 µM) and distilled water at different growth stages (tillering, booting and heading) along with a control (no spray). Crop growth rate and net assimilation rate substantially improved under both sowing dates in response to H2O2. Better performance of wheat regarding growth attributes indicated the positive role of H2O2 in protecting the total soluble proteins. The findings further revealed that H2O2 triggered up-regulation of different antioxidants (SOD, POD, and CAT) which offset the negative impacts of supra optimal temperatures that persisted in late planted wheat. Collectively, we concluded that application of H2O2 at heading stage improved growth and heat tolerance in late sown wheat. [ABSTRACT FROM AUTHOR]