Agro-climatic indices for predicting phenology of wheat (Triticum aestivum) in Punjab

Abstract

The study of phenology of wheat (Triticum aestivum L. emend. Fiori & Paol.) crop in relation to various euergy summation iudices, viz accumulated growing degree-days, accumulated helio-thermal units, cumulative solar radiation
and cumulative pan evaporation, for 8 crop seasons of 1986-87 to 1993-94 was conducted at Ludhiana. A comparison of
various agro-climatic indices revealed that accumulated growing degree-days can be used as the best index to predict
various phenophases under Punjab conditions, as it gave the lowest coefficient of variation under early-, normal- as well
as late-sown conditions, From sowing to complete emergence and also during intennediate phenophases representing
reproductive phase, the delay in sowing reduced the cumulative energy attained, but no such trend was observed during the vegetative phase.