Abstract:
The evaluation of past climate change is needed for selecting appropriate adapting strategy for future. This
simulation study was mainly aimed to find the probable difference between sowing dates for response of four
chickpea cultivars to past climate change. Firstly, the model CYRUS was recoded in QBASIC programming. Then
phenology of cultivars Jam, Hashem, Arman and Beauvanij, seeded at day of year 50, 70 and 90, was evaluated
during years 1961 to 2003 in Gorgan, Iran. The changes in some climatic variables were also studied. Results
revealed that the solar radiation has been decreased for month December. Although the value of maximum
temperature appeared to be the same across years 1961 to 2003 for all months, that of minimum temperature tended
to show increasing trend for May and August. The increase in number of days with temperature higher than 35 oC
was considerable for April and October, but negligible for other months. The warming of night temperature was
significant only for May and August. It found about 34 mm per 43 years decrease in monthly rainfall for March. The
rate of increase in number of days with rainfall was 0.0737 day year-1 for December. Nearly similar situation was
found for number of days with rainfall lower than and/or equal to 10 mm. The change in number of days with rainfall
higher than 10 mm and lower and/or equal to 30 mm was in decreasing manner (March, October and December).
The length of time from sowing to emergence appeared to be constant across past years. The advance in flowering
(R1) was true only for cultivar Jam seeded at day of year 70. The length of period from R1 to pod initiation (R3) has
been diminished for sowing at day of year 70 (Jam and Arman). Only cultivar Hashem seeded at day of year 90
tended to have decreasing trend for length of period between R3 and pod filling. It found one day (per 43 years)
decreases from pod yellowing to maturity for cultivar Beauvanij seeded at day of year 70. Based on these findings,
and on the fact that future climate change is predicted using past changes, it seems that the adaptation strategies for
future, including agronomy and/or breeding programs, may be not the same for different sowing dates of chickpea.
