RESUMO
An experiment was conducted in Iraq, to study the effect of temperature and light accumulations [which resulted from growing plant at different sowing dates]. On the vegetative; flowering and yield parameters for three rice cultivars Oryza sativa, L. at two locations, Abbasyia and Hira, Najaf. Factorial experiment with Spilt Plot Design was used with three replications. Main plots included three cultivars [Mushkhab 1, Anber 33 and IPA 1]. Sub - plots included sowing dates that were randomly distributed and applied from 15/5/1998 to 10/7/1998. Temperatures light accumulations were as the following: 1621; 1524 and 142 [1] heat units and 1795; 1679; and 1494 [2] light hours for cv. Mushkhab 1. And 1524; 1342 and 990 h.u. and 1679; 1494 and 1117 1. h. for cv. Amber 33. And 1524; 1342 and 1158 h.u. and 1679; 1494 and 13071. h. For cv. IPA 1. This experiment revealed that: There were significant effects for both heat and light accumulations during the whole growing period on the flowering and growth characteristics, particularly, spike emergence and both repining and harvest periods. There was a slight effect for the tow locations in general, on the tested cultivars during the different growing periods in respect to their flowering growth parameters, but, in general, Hira soil gave begetative growth characteristics better than Abbasyia Soil. Cultivars showed different growth stages as an effect of temperature and light Accumulations