الفهرس 
INTRODUCTION
Effect of sowing dateOnly 14 pages are availabe for public view
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Abstract
This study was carried out at Agronomy Department, Faculty of Agriculture, Assiut university, the experiments were carried out at El-Dakhla Oasis in the New Valley Governorate, Egypt, during the two growing seasons of 2013/2014 and 2014/2015 to study the performance of some barley cultivars under delayed sowing and different nitrogen levels in the New Valley. Three experiments were conducted separately for each sowing date (1st Dec., 20th Dec. and 10th Jan. i.e. S1, S2 and S3) in both seasons. The randomized complete block design using split plot with three replications was employed, where the nitrogen fertilizer rates (50, 70 and 90 kg. N/fed. i.e. N1, N2 and N3) were assigned in the main plots, while the cultivars (Giza 123, Giza 129 and Giza 130 i.e. Cv. 1, Cv. 2 and Cv. 3) were allocated in the sub-plots. The plot area was 10.5 m2 including 3x3.5 m (1/400 fed.). The results could be summarized as the following: 1- Growth traits: 1.1- Number of days to 50% heading: - The sowing dates had a highly significantly effected on days to 50% heading in the both seasons, as well as nitrogen fertilizer and cultivars had significantly effect on this trait in the 2nd season only. - The best 50% heading were observed with sowing at 10th Jan. (62.59 and 67.34 days) in the 1st and 2nd seasons, respectively, as well as the best 50% heading values were observed with 70 kg. N/fed. (72.11 days) and Giza 129 cultivar (72.41 days) in the 2nd season only. - The number of days to 50% heading had non-significant affected with the all first and second order interactions in the both seasons. 1.2- Flag leaf area (cm2): - The sowing dates, nitrogen fertilizer and cultivars had a highly significantly effected on the flag leaf area in the both seasons. - The highest flag leaf area (14.54 and 6.38 cm2); (13.58 and 5.81 cm2) and (14.48 and 7.51 cm2) were recorded with 20th Dec.; 90 kg. N/fed. and Giza 123 cultivar in the 1st and 2nd seasons, respectively. - The flag leaf area had a highly significantly affected with the all first and second order interactions in the both seasons. - The first order interactions i.e. S2xN1 and S2xN3; S2xCv1 and N3xCv1 as well as the second order interactions; S2xN3xCv1 gave the highest flag leaf area values in the 1st and 2nd seasons, respectively. 1.3- Number of days to physiological maturity: - The sowing dates and cultivars had a significantly effected on number of day to physiological maturity in the both seasons. - The best physiological maturity values were obtained with (113.1 and 112.7 days) and (102.6 and 105.8 days) were achieved with sowing at 1st Dec. and Giza 129 and Giza 130 cultivars in the 1st and 2nd seasons, respectively. - Physiological maturity exerted a significantly influenced with SxN interactions in the 2nd season only and SxCvs, NxCvs and SxNxCvs interactions in the 1st season only. - The first order interactions i.e. S3xN2 in the 2nd season; S3xCv3 and N2xCv2 as well as the second order interactions S3xN3xCv2 in the 1st season gave the best physiological maturity values. 1.4- Plant height (cm): - The plant height had a highly significantly affected with sowing dates and nitrogen fertilizer in the both seasons as well as cultivars in the 2nd season only. - The tallest plants were recorded with sowing at 1st and 20th Dec. (124.3 and 128.2 cm), 90 kg. N/fed. (121.5 and 115.8 cm) and Giza 129 and Giza 123 cultivars (119.5 and 119.0 cm) in the 1st and 2nd respectively.