Optimizing Sowing Window and Cultivar Selection for Sustainable Foxtail Millet (Setaria italica L.) Cultivation in Punjab, India

Heat use efficiency plays a vital role in determining the growth and yield performance of foxtail millet under varying thermal regimes. The field investigation was carried out to evaluate the growth, phenology, yield and heat use efficiency of three foxtail millet cultivars (SiA-3156, Punjab Foxtail millet-3, and PFM-2) under six sowing dates (starting end April to mid-July) to expose the crop to a range of temperature conditions. The significant variation in HUE among cultivars and sowing dates, with early-sown crops generally exhibiting higher efficiency due to optimal thermal accumulation during critical growth phases was observed. Early sowing (S₁-26 ^th April) significantly improved growth and yield, with the highest grain yield of 1.66 t ha¹ while late sowing (S_6- 11^th July) showed reduced grain yield despite higher biological yield. The delayed sowings resulted in shortening grain filling duration, and lowering both biomass accumulation and yield. The S₁-26^th April sown crop accumulated 1738.8 growing degree days, which was lower than that other treatments, yet exhibited the highest heat use efficiency and grain yield. Among the cultivars, Punjab Foxtail Millet-3 outperformed the others, showing the highest HUE and producing the maximum grain and biological yields, followed by PFM-2. These results highlight the critical role of timely sowing and cultivar selection in optimizing foxtail millet productivity.