Abstract
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.
