Heat unit requirements for Phenophases of wheat genotypes as influenced by different thermal regimes: A review

Abstract

Seasonal temperature is important climatic factor which has profound effects on the yield of rabi crops. Changes in seasonal temperature affect the grain yield, mainly through phonological development processes. Winter crops are especially vulnerable to high temperature during reproductive stages and differential response of temperature change (rise) to various crops has been noticed under different production environments. The occurrence of different phonological event during growing season of any crop and the effect of temperature on plant growth can be inferred using accumulated heat units or growing degree days (GDD). Temperature based agro meteorological indices such as growing degree days (GDD) and heat use efficiency (HUE) can be quite useful in predicting growth and yield of crops. Heat use efficiency (HUE), i.e. efficiency of utilization of heat in terms of dry matter accumulation is an important aspect, which has great practical application.