Mulching, farmyard manure and exogenous application of osmo-protectants confer terminal heat tolerance in wheat (Tritcum aestivum)

A field experiment was conducted at Ludhiana, Punjab (India) with combinations of 2 sowing dates [timely sowing (10 November) and late sowing (15 December)] and 6 heat-stress-management treatments includes recommended dose of fertilizer (RDF: 150 : 27.3 : 24.8 N, P and K kg/ha), RDF + FYM (10 t/ha farmyard manure), RDF + mulch (rice straw mulch @ 4 t/ha), RDF + FYM + mulch, RDF + FYM + mulch + ZnSO₄ (0.5%) and RDF + FYM + mulch + KCl (0.2%) in randomized block design with 3 replications during 2015-16 and 2016-17. The timely sown wheat showed higher emergence count, canopy air temperature difference, normalized difference vegetative index, days to earing/maturity, yield attributes, grain yield and water-use efficiency than the late-sown one. The grain yield recorded in RDF + FYM + mulch + KCl was the highest, which was statistically similar to RDF + 10 t FYM, RDF + Mulch, RDF + FYM + mulch and RDF + FYM + mulch + ZnSO₄. The grain yield and water-use efficiency recorded in RDF + FYM + mulch + KCl, RDF + FYM + mulch + ZnSO₄ and RDF + FYM + mulch was at par under late sown condition. Under late-sown conditions, RDF + FYM + Mulch + KCl can be used to ameliorate the adverse effect of terminal heat stress on wheat and enhance the grain yield and water use efficiency.