Ali abdalla basyouni abou-khalifa
A field experiment was conducted at Rice research and training center (RRTC) – Sakha, kafr- El sheikh, governorate, Egypt in 2010 season to study Response of some rice cultivars (H1 hybrid rice and Giza 177 inbred rice) to different methods of irrigation withholding under different sowing dates. Nitrogen fertilizer was used as urea form (46.5% N) in two splits; 2/3 were added as basil and mixed in dry soil before irrigation water and 1/3 was added at panicle initiation. Under different five sowing dates, April 10th, April 25th , May 10th, May 25th and June 10th. Three irrigation withholding, (W1) Irrigation withholding after 10 days from complete heading. (W2) Irrigation withholding after 15 days from complete heading. (W3) Irrigation withholding after 20 days from complete heading. Seedling age at transplanting was 26 days from sowing and by 20X20 cm planting spacing. All agricultural practices were applied as recommended for each cultivar. A split split plot design with four replication was used, five sowing dates allocated in the main plots. Three irrigation withholding were allocated in sub-plots and two rice cultivars were allocated in the sub-sub plots. Main results induced that maximum tillering, panicle initiation, heading dates, grains filling rates (G F R) at five stages, Leaf area index, and grain yield (Ton/ha) were the highest value at (5-10 days after complete heading) growth stage with (W2) of two rice varieties under five sowing dates. So sowing dates at April 25th gave the highest value to all studied characters with H1 hybrid rice variety. While June 10th date of sowing with Giza 177 inbred rice gave the lowest value with all traits under study. The interaction between H1 hybrid rice variety with (W2) irrigation withholding gave the highest value of leaf area index, GFR at different stages. And H1 with April 25th date of sowing gave the highest value of L.A.I. and chlorophyll content.
