Ø  The best adaptation of the crop is in areas with moderate temperature and sub- humid to semi-arid conditions.

Ø  Environmental conditions cause wide fluctuations in emergence, growth, grain development, ripening and nutritional quality of the crop.

Ø  Wheat is basically a temperate climate plant, grown in the summer season in temperate region and winter or rabi season in the sub - tropics.

Ø   A mean daily temperature of 15 to 200c is the optimum for its growth and development.

Ø  Higher temperatures of about 30 - 350C  have in general detrimental effect to the crop performance. the crop can withstand intense cold condition. the optimal range of temperature for the germination of winter wheat and for its vegetative growth is 15 to 200C .

Ø  Minimum, optimum and maximum cardinal temperatures for germination of wheat crop are 3 to 4.50C, around 250C and 30- 320C, respectively. high temperature during rapid growth and tillering periods results in poor tillering, low number of effective tillers, poor growth rate, short shoot height, low lai, short ears with lower number of spikelets, lower fertilization, lower grain weight and lower quality.

Ø  High soil moisture content is useful for high germination, good start of seedlings, good seed setting and development.

Ø  The crop shows resistance to drought though it is highly sensitive to moisture stress during the period from shooting to advanced heading stages.

Ø  Bright sunny days with dryness and cooler nights during ripening period give better sized quality grains.

Ø  Optimum rainfall requirement is 50-87.5 cm during the growing season and the total water requirement is 45-55 cm for different varieties and seasonal conditions. daily cu varies from 0.17 to 0.87 cm from emergence to grain filling, the high range being 0.62cm for the period from boot to dough stages.

Ø  The information on the critical growth stages in areas with limited water supply is useful.

Ø   A delay in sowing to avail the maximum advantage of cool weather leads to poor crop stands on account of decreasing soil moisture