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Abstract Two field experiments were conducted at the Experimental Farm of Rice Research and Training Center (RRTC), Sakha, Kafr El-Sheikh, Egypt during 2011 and 2012 seasons to investigate the effect of irrigation intervals, organic and mineral fertilization on the growth, grain yield, yield components and some technological characters of grains as well as some rice water relations of hybrid rice. A split split–plot design, with three replicates, was used. The main plots were devoted to four irrigation treatments namely: 1- Continuous flooding (CF). 2- Irrigation every 6 days (6-day). 3- Irrigation every 8 days (8-day). 4- Irrigation every 10 days (10-day). However, the sub plots were occupied by two rice genotype namely: 1- Egyptian hybrid 1 (EHR1). 2- SK2046hybrid (SK2046H) While, the sub-sub plots were occupied by seven fertilizer treatments, as follows:- T1-Zero fertilizer (control). T2-160Kg N ( N) +40 Kg P2O5 (P)+ 60 Kg K2O(K) / ha (recommended level). T3- Compost (5 t/ ha). T4- 40 Kg N ( N) + 10 Kg P2O5 (P)+15 Kg K2O (K) / ha + compost (5 t/ha). T5- 80 Kg N ( N) + 20 Kg P2O5 (P) + 30 Kg K2O (K) / ha + compost (5 t/ha). T6- 120 Kg N (N)+ 30 Kg P2O5 (P)+ 45 Kg K2O (K) / ha + compost (5 t/ha). T7- 160 Kg N (N) + 40 Kg P2O5 (P) + 60 Kg K2O (K) / ha + compost (5 t/ha). Samples of rice plants were collected at booting and heading stages to determine the growth characters. Characters studied: 1- Vegetative growth: Leaf area index - dry matter production (g/m2) - crop growth ratedays to 50% heading- plant height - number of tillers/m2. 2- Grain yields and its attributes: Number of panicles/m2 – total grains per panicle – unfilled grains % - panicle weight – panicle length – 1000 grain weight - panicle density - sink capacity – grain yield t/ha – straw yield (t/ha) – biological yield (t/ha) – harvest index. 3- Grain quality characters: The percentage of hulling , milling , head rice and broken rice. 4- Chemicals analysis: Nitrogen, phosphorus, potassium and protein percentages in milled rice grains . 5- Water relations: 1- Total water used( m3 / ha) 2- Water saved(%) 3- Water productivity (kg grains/ m3 water ) The results obtained could be summarized as follows: A- Irrigation intervals- 1- The effect of irrigation treatment on growth attributes were significant in both seasons. Leaf area index, dry matter, crop growth rate, days to heading, plant height and number of tillers / m2 significantly decreased as irrigation intervals increased up to 10 days. Continuous flooding gave the highest values of all previous characters as well as earlier heading followed by irrigation every 6 days. On the other hand, irrigation every 10 days gave the lowest values of all traits and delayed heading. 2- Grain yield and its attributes significantly affected by irrigation treatments. Whereas, in both seasons, continuous flooding followed by irrigation every 6 days gave the highest values as number of panicles /m2, total number of grains/panicle, panicle weight, panicle density, sink capacity, 1000-grain weight, grain yield and harvest index with no significant between them in both seasons. Also, continuous flooding gave the highest value of panicle length, straw yield and biological yield followed by irrigation every 6, 8 days While irrigation every 10 days gave the lowest values of all studied characters except unfilled grains percentage. 3- Grain quality characters significantly affected by irrigation treatments Whereas, in both seasons, continuous flooding gave the highest value of hulling %, milling %, head rice %, and protein content followed by irrigation every 6 and 8 days While, irrigation every 10 days gave the lowest values of all studied characters expect broken rice percentage. 4- Percentage of nitrogen, phosphorus and potassium in grains significantly affected by irrigation treatments. Whereas, in both seasons, continuous flooding gave the highest value of nitrogen %, phosphorus % and potassium % in grains followed by irrigation every 6 and 8 days. While, irrigation every 10 days gave the lowest values of this characters in both seasons. B - Effect of genotypes :- 1- EHR1 produced the highest values of dry matter production in both seasons also, number of tillers in first season compared with SK2046H. On the other hand, there were no significant between other characters under study. 2- EHR1 gave the highest values of grain yield and its attributes compared with SK2046H hybrid. While, SK2046H hybrid rice gave the highest values of panicle length and unfilled grains percentage in both seasons .However, no significant was found between genotypes for number of panicles/m2, 1000 grain weight and harvest index in both seasons. Also, sink capacity in second season and panicle weight in first season. 3- EHR1 gave the highest values of hulling, milling and head rice percentage compared with SK2046 hybrid. While, SK2046H hybrid rice gave the highest values of broken rice percentage, in both seasons. However, there were no significant between genotypes in protein content in both seasons. 4- EHR1 gave the highest values of phosphorus and potassium percentage in grains compared with SK2046H hybrid rice. While, no significant between genotypes was found in nitrogen content in both seasons. C- Effect of fertilizer treatments:- 1- Results revealed that characters under study were significantly by fertilizer treatment in both seasons. The application of 160N+40P+60K+compost (T7), 160 N+40P+60K (T2) and 120N +30P +45 K + compost (T6) recorded the highest values of most studied vegetative characters(dry matter g/m2, LAI , crop growth rate , days to heading 50% , plant height , No. of tillers /m2) compared with other treatments under study. While, T1 (control) gave the lowest values of this characters in both seasons of study 2- Plants fertilized with 160N+40P+60K+compost (T7), 160 N+40P+60K (T2) and 120N +30P +45 K + compost (T6) gave the highest values of most grain yield and its attributes( No. of panicle /m2, panicle length , No. of total grains / panicle , sink capacity , panicle density , 1000 grain weight, panicle weight, grain yield , straw yield , biological yield and HI) compared with other treatments under study. While, T1 (control) gave the lowest values of grain yield and its attributes except unfilled grains percentage in both season of study . 3- Plants treated with . 160N+40P+60K+compost (T7), 160 N+40P+60K (T2) and 120N +30P +45 K + compost (T6) recorded the highest values of most grain quality characters( hulling , milling and head rice percentage ) compared with other treatments under study. While, T1 (control) gave the lowest values of broken rice percentage. 4- The application of 160N+40P+60K+compost (T7), 160 N+40P+60K (T2) and 120N +30P +45 K + compost (T6) recorded the highest values of nitrogen , phosphorus ,potassium and protein percentage in grains compared with other treatments under study. While, T1 (control) gave the lowest values of this characters in both seasons. D - Effect of interactions :- 1-There was significant interaction between the tested irrigation intervals and varieties for dry matter at booting stage, unfilled grains%, panicle length and panicle density, plants of EHR1 genotype produced the highest significant values of dry matter at booting stage when they were irrigated by continuous flooding .Also, plants of EHR 1 genotype recorded the highest values of panicle density and hulling% when they were irrigated by continuous flooding and irrigation every 6 days . On the other hand, Plants of SK2046 H genotype produced the highest significant values of panicle length when they were irrigated by continuous flooding and unfilled grains% when they were irrigated by10 days . 2- There was significant interaction between the tested irrigation intervals and fertilizer treatments for dry matter production at heading, crop growth rate, panicle weight, sink capacity, grain yield, straw yield ,biological yield, head rice% and broken rice%. In favour of continuous flooding and irrigation every6 days with160N+40P+60K+compost (T7), 160 N+40P+60K (T2) and 120N +30P +45 K + compost (T6) without significant between them . On the other hand, The highest values of broken rice% were produced by irrigation every 8 and 10 days with control treatment (T1). 3-The interaction between the tested genotypes and fertilizer treatments were not significantly for all studied characters in both seasons . 4- The interaction between the factors under study were not significantly for all studied characters in both seasons . E - Water relations:- 1- Total water used( m3 / ha ):- The amount of water input, before starting irrigation intervals, for land preparation of both nursery and permanent field, raising nursery for thirty days and through ten days after transplanting and before treatments application were 3071.5 and 3000.5 in 2011 and 2012 seasons, total water used in Continuous flooding were 14276 and 14190 m3/ha in both seasons. While, increasing irrigation intervals from 6,8 up to 10 days decreased total water used in both seasons . 2- Water saved( %) :- Increasing irrigation intervals from 6,8 up to 10 days decreased total water used and saved total water by about (9.82 , 10.35 % ) , ( 16.74 , 17.39 %) and (25.35 , 25.44 %) compared to continuous flooding in both season . 3- Water productivity (kg grains/ m3 water ) :- Irrigation every 6 days recorded the highest water productivity as compared with other treatments in both seasons . EHR1 gentype produced the highest values water productivity Kg/m3 in second season . The application of with160N+40P+60K+compost (T7), 160 N+40P+60K (T2) and 120N +30P +45 K + compost (T6) recorded the highest values water productivity Kg/m3 without significant in both seasons . There was significant interaction between the tested irrigation intervals and fertilizer treatments on water productivity in both seasons infavour of irrigation every 6 days with 160N+40P+60K+compost (T7), 160 N+40P+60K (T2) and 120N +30P +45 K + compost (T6) without significant between them. |