عنوان مقاله [English]
In order to estimating model and considering day length and temperature development stages the growth period and plant development rate and role of factors and equations to estimate development stages, an experiment was conducted in two years, 2011 and 2012 in Isfahan. A split plot layout with randomized complete block design with 3 replications was used. The planting dates in 2011 were 5th May, 21th May, 5th Jun, 21th Jun, 5th July, 21th July, and in 2012 were 5th Mar, 21th Mar, 5th Apr, 21th Apr, 5th May, 21th May, 5th Jun and 21th Jun. Isfahan-14 and IL111 were used, which were late maturity and early maturity, respectively. Meteorological data in two years included daily maximum, minimum and mean temperatures and the mean of each temperature variable considered for period length. The results showed that duration of all three development stages were reduced as planting was delayed. From emerging to maturity in two cultivars, mean temperature explained the most part of variation. From emerging to 10 percentage of flowering DL3 and from segmented stage to maturity, DL3 explained most part of variation for two cultivars. It can be concluded that lines showed the same reactions to day length and variables, and day length play an important role on changes of development stages, but the rate of these factors were different.