تأثير موعد الزراعة و التراكم الحراري في نمو و إنتاجية الرز

Abstract EN

A field experiment was conducted of the season 2005 .sowing dates were (28 May, 7June , 17June , 27June , 7 July , and 17 July) at Al – Essa- Kufa Najaf.

Randomized Complete Block Design (RCBP) was adopted to determine the suitable rice sowing date of Amber 33 and heat accumulation effect on growth parameters and crop productivity.

Results showed that there was a significant effect for sowing dates on vegetative and flowering growth parameters for plant.

The first three early sowings dated (28 May, 7 June and 17 June) were significant in most of vegetative, flowering, root parameters and dry weights, where as, the number of tillers and spikes / plant were not significant between the six sowing dates .

Results indicated also, that plants of the third sowing (18 June) produced significantly in the amount of yield .

(692.6 kg / Donam) , as well as , the first there sowing dated were that best in productivity early due to the collectiv of more thermal units .

On the other hand the late sowing dates( 27June , 7July , and 17July) gained the least productivity .

The productivity of the last sowing date (17July) was (33.8 kg / Donam) .

It could be recommended that the best period for growth and productivity of rice , Amber 33 in the middle of June according to the increase in heat accumulation.