CROP

Figure 5 - Thermal requirements for winter wheat

CROP

WINTER WHEAT (C3/I)

CLIMATES

Subtropics, Temperate, Boreal

PHOTO-SENSITIVITY

Day Neutral/Long Day

GROWTH
CYCLES (days) [1]

a + b
30 + 90, 35 +105, 40 +120, 45 +135

Sub-optimal Conditions

Optimal Conditions

TEMPERATURE
PERIODS [2]

Percentage of Growth Cycle

1^st req.

2^nd req.

1^st req.

2^nd req.

< -5 °C

-5-0 °C

0-5 °C

5-10 °C

< 50 % b

> 16.7 % b

< 50 % b

> 16.7 % b

10-15 °C

< 100 % b

15-20 °C

20-25 °C

25-30°C

< 33.3 %b

> 30 °C

30-25 °C

< 50 % b

25-20 °C

100% a

20-15 °C

15-10 °C

10-5°C

5-0 °C

0-5°C

< -5 °C

Accumulated
temperature
during growth
cycle (TSgc)[3]

TSgc > 1300
(post dormancy)

TSgc > 1500
(post dormancy)

LGP_t=5

< 365

Dormancy

Required

Permafrost tolerance

No permafrost

[1] a: pre-dormancy part of growth cycle; b: post-dormancy part of growth cycle.

[2] A9-A1: temperature periods with increasing temperatures, i.e., during winter to summer; B1-B9: temperature periods with decreasing temperatures, i.e., from summer to winter.

[3] Accumulated temperature during post-dormancy part of growth cycle.