Growth, Yield and Physiology of Wheat Influenced by Osmoprotectants Application and Different Sowing Dates

With climate change intensifying heat episodes, developing heat-tolerant wheat varieties and adopting heat-mitigating agronomic practices such as optimal sowing dates and use of osmoprotectants has become essential for sustaining wheat production.

The field experiment was conducted during Rabi season 2022-23 at Research farm Department of Agriculture, Guru Nanak Dev University, Amritsar to study the effect of sowing dates and foliar application of osmo-protectants on growth, physiology and yield of wheat (Triticum aestivum L.). The experiment was conducted using a split-plot design, with sowing dates (October-20, November 20 and December 20) assigned to the main plots and foliar application (Control, water spray, potassium nitrate @ 2%, salicylic acid (100 ppm), sodium nitroprusside @ 800 µg/ml, zinc sulphate heptahydrate @ 1%) to the sub plots. The experiment had three replications.

Growth parameters including plant height, leaf area index and dry matter accumulation were significantly higher in early sowing (October 20), while maximum emergence count and yield were recorded under November 20 sowing. Late sowing (December 20) resulted in reduced pollen viability, membrane stability index, relative water content and yield, primarily due to exposure to higher temperatures at the reproductive stage. Among osmo-protectants, sodium nitroprusside (SNP @ 800 µg/ml) and salicylic acid (100 ppm) significantly enhanced pollen viability, proline accumulation, relative water content and grain yield compared to control and other treatments.