Photothermal Quotient-An Effective Thermal Index for Evaluation of Lentil (Lens culinaris L.) Phenology and Yield in the Lower Gangetic Plains

Background: Sowing time and variety-specific genetics influence the phenological development of lentil (Lens culinaris L.), affecting its heat solar energy utilization for attaining satisfactory yield. The present study was conducted to assess how different thermal indices behaved in explaining variation phenology yield components with corresponding effects on varieties grown under varying sowing dates. Methods: experiment comprised four dates main plots five sub-plots, laid out a split-plot design replicated thrice. phenology, were recorded. computed correlation regression analyses used their traits Result: after 7th November reduced by 13.6-22.5 kg ha-1 day-1 0.9-2.1% absolute relative basis, respectively. WBL 77 HUL 57 less sensitive temperature fluctuations resulting stable performance regimes. Despite significant traits, growing degree days explained 82.0-89.0%, while photothermal quotient (PTQ) 92.0-96.0% total PTQ emerged as reliable predicting index might be breeding climate-smart varieties.