A factorial experiment was conducted within split-split plot design with three replicates. Four genotypes seeds (Regalona, Q-37, KVL-SR2, and Q21) were planted in the sub plots while six water treatments distributed in the main plots. They were ordinary river irrigation (S0), stress at emergence (S1), branching (S2), at ear formation (S3), at flowering (S4), and at maturity (S5). Irrigation water was applied in the normal irrigation when 50-60% of the available water was depleted and one irrigation was omitted from the water stress treatments. Reference and actual evapotranspiration, pan evaporation, yield, crop coefficient, and water use efficiency were calculated. Mean irrigation requirement for the four genotypes based on irrigation scheduling was 230.8 mm, decreased by 14 and 17% under stress conditions of the drought tolerant stages. Grain yield ranged between 3.1 and 5 Mg ha-1 for water stress treatments compared to 5.6 and 4.2 mg. ha-1 for normal irrigation treatments. Genotype Q21 gave the highest yield and differed significantly from others. Field water use efficiency ranged between 1.6 to 1.1 kg m-3 and crop water use efficiency 1.38 to 2.22 kg m-3. KVL-SR2 and Q21 showed the highest efficiency (1.87 kg m-3). Results indicated that the stage of ear formation and flowering are the most tolerant to water stress. On the other hand, the branching, and maturity were critical stages with high reduction in yield under stress conditions.

Abstract

Cellulose acetate (CA) is a biopolymer produced from fronds of date palm (type teperzal) which were taken from the Iraqi groves. The steps used to produce (CA); pretreatment, bleaching, acetylation and hydrolysis. Organosolv pretreatment method was used to remove high lignin content under mild and severe conditions using NaOH as a catalyst at the concentration (0.03) M. The conditions of Organosolv pretreatment were used: temperature (125 °C mild, 160 °C severe), pretreatment time 90 min, and ethanol: water ratio 40:60 wt/wt. The acetylation of cellulose with acetic acid was used to produce cellulose tri-(CTA) and di-(CDA) acetate for two ways: with treated and untreated fronds. The conditions of acetylation reaction were used: temperature (50-55) °C and time (1, 2 & 3) h. The product was characterized by the solubility test, titration method and Fourier transform infrared spectroscopy (FTIR). The results showed that the high percentage of lignin removed was (93%), the best degree of substitution (DS) for (CTA) and (CDA) were 3.01 and 2.60. As well as the excellent solubility percentages for (CTA) with chloroform and mixture of chloroform/methanol were 90% and 84%, respectively. While the solubility percentage for (CDA) with acetone was 95%, these result occurred at pretreatment temperature 160°C, pretreatment time 90 min and reaction time 3 h.