Barley Grain Yield and Protein Content Response to Deficit Irrigation and Sowing Dates in Semi-Arid Region

Abstract

The present study was conducted to investigate the relational effects of various sowing dates and deficit irrigation on grain yield, protein and yield components of barley, in a semi-arid region (southern part of Iran) during growing seasons 2011-2012 and 2012-2013. A Split plot layout within a randomized complete block design with three replications was used. Main plots were selected as Irrigation treatments with varying water irrigation levels consisting of: (1) full irrigation, FI, (2) 0.75 FI, (3) 0.5 FI and (4) Dry land (rain-fed) during both growing seasons. Sub plots were the sowing dates consisted of: (1) 23th October (T1), (2) 6th and (3) 22th November (T2 and T3) and (4) 6th December (T4). The interaction of different irrigation levels and sowing dates had a significant impact (p<0.05) on grain yield, grain and straw protein, 1000-grain weight, plant height, biomass, water use efficiency (WUE), and crop evapotranspiration. Results revealed that the largest amount of protein was obtained in the latest sowing date (T4) at dry land treatment in two consecutive years. Full irrigation treatment showed the largestrate of dry matter accumulation (14.72 and 15.25 Mg.h-1 for the first and second years, respectively), while the smallest rate was seen in the rain fed treatment (4.22 and 7.43 Mg.h-1 for the first and second years, respectively). The largest yield was obtained with the 23th October (T1) sowing date in full irrigation treatments (FI). The largest water use efficiency was achieved with 0.5FI and the earliest sowing date (T1).