Response of some Barley Cultivars to Late Sowing Dates and Nitrogen Fertilizer Rates Under the New Valley Condition

This investigation was 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 response of some barley cultivars to late sowing date and nitrogen fertilizer rates under the New Valley condition. Three experiments were conducted separately for each sowing date (1^st Dec., 20^th Dec. and 10^th 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:
-  Sowing date at 1^st Dec. recorded the highest mean values for the plant height and spike length in the 1^st season, and 1000 grain weight in the both seasons. Moreover, the tallest plants and the greatest number of spikes/m² in the 2^nd season and the maximum grain yield/fed. in the both seasons were recorded by sowing date at 20^th Dec.
-  Number of spikes/m², 1000 grain weight and grain yield/fed. increased with increasing N fertilizer rates up to 70 kg N/fed., as well as the tallest plants was obtained by 90 kg N/fed. rate in the both seasons.
-  Giza 123 cultivar surpassed the Giza 129 and Giza 130 cultivars and gained the highest mean values for 1000 grain weight and grain yield/fed. in the both seasons and number of spikes/m² and plant height in the 1^st and 2^nd seasons, respectively, while Giza 129 cultivar gave the tallest plants and the greatest number of spikes/m² in the 1^st and 2^nd seasons, respectively.
-  The S₃xN₁ (10^th Jan. x 50 kg N/fed.) interaction treatments gave the minimum values for the plant height in the both seasons and number of spikes/m² in the 1^st season, as well as S₃xN₃ (10^th Jan. x 90 kg N/fed.) interaction treatments gave the minimum values for 1000 grain weight and grain yield/fed. in the both seasons. However, the maximum mean values for 1000 grain weight and grain yield/fed. were obtained by S₂xCv.1 (20^th Dec. x Giza 123 cultivar) interaction treatment and N₂xCv.1 (70 kg N/fed. x Giza 123 cultivar) interaction treatments in the both seasons.

-  The highest mean values for 1000 grain weight and grain yield/fed. in the both seasons and number of spikes/m² in the 2^nd season were achieved by S₂xN₃xCv.1 (20^th Dec. x 90 kg N/fed. x Giza 123 cultivar) interaction treatments.