Evaluation of the Genetic Variability in Utilization Efficiency of Some Agricultural Inputs (water and fertilizers) for Some Cultivated Barley (Hordeum vulgare L.) Varieties

The study was carried out at Abi Jerash Farm, Faculty of Agricultural Engineering, University of Damascus, over two consecutive agricultural seasons (2017-2018, 2018-2019), the performance of seven varieties of locally certified barley, which were obtained from the National Breeding and Genetic Improvement Programs, were evaluated under rainfed conditions, and supplementary irrigation, determining the most efficient varieties for the utilization of agricultural production inputs (water, mineral fertilizers) available in limited quantities, in the target environmental area, depending on some morphological, physiological, biochemical, quantitative and qualitative characteristics. The experiment was laid according to the design of the randomized complete blocks (RCBD), with three replications for each variety and treatment (rainfed and supplementary irrigation).It is noted with regard to the interaction of all the studied variables with each other, that the mean plant height was the highest significantly during the second season with higher precipitation under supplementary irrigation conditions of the six-rows barley variety Fourat5 (140.00 cm), while it was significantly lower during the first growing season with lesser precipitation under rainfed conditions for the barley cultivars Araby Aswad (63.53 cm). The mean average of the peduncle length was significantly higher during the second growing season under supplementary irrigation conditions in the varieties Fourat4, improved Araby Abiad, and Araby Aswad, and during the first growing season under supplementary irrigation conditions in the two barley varieties Fourat5, Araby Aswad without significant differences among them (20.83, 20.28, 20.08, 19.44 and 19.39 cm, respectively), while it was significantly the lowest during the first growing season, of lesser precipitation under rainfed conditions for the barley cultivars Araby Aswad, Fourat5, Fourat6, Fourat4, and Fourat7, without significant differences among them (10.39, 10.89, 11.28, 11.45, 11.69 cm, respectively). The average flag leaf area was significant higher during the first growing season under supplementary irrigation conditions in the two barley varieties improved Araby Abiad, and Fourat5 without231significant differences between them (14.50 and 13.44 cm2 respectively), while it was significantly the lowest during the first growing season under rainfed conditions in the barley variety Araby Aswad, and in the variety Fourat7 during the first and second growing seasons, and during the first growing season under rainfed conditions in the barley varieties Furat6, Furat4, and Furat9 without significant differences among them (4.05, 4.51, 5.11, 5.38, 5.56 and 5.63 cm2, respectively).The mean of the sub flag leaf area was significantly higher under during the second growing season under supplementary irrigation conditions for the two varieties of barley Fourat 9, and Fourat5 without significant differences between them (27.82 and 26.66 cm2 respectively), while it was significantly the lowest under the rainfed conditions during the first growing season in the variety Foura6 (8.70 cm2). The mean of the leaf area index was significantly the highest under supplementary irrigation conditions during the second growing season in the barley cultivar Fourat5 (8.91), whereas it was significantly the lowest during the first growing season under rainfed conditions in the barley varieties improved Araby Abiad, Araby Aswad, and Fourat6, without significant differences among them (2.10, 2.24 and 2.37 respectively).The average of solutes leakage through the cytoplasmic membranes was significantly higher during the first and second growing seasons under the rainfed conditions in the barley cultivar Fourat9, and during the first growing season under rainfed conditions, in the barley cultivar Fourat6 without significant differences between them (82.87, 80.33, 79.20% respectively), while it was significantly the lowest during the second growing season under supplementary irrigation conditions in the barley varieties Fourat6 and Fourat4 without significant differences between them (13.03 and 14.36% respectively). The average water use efficiency was significantly the highest during the second growing season of higher precipitation under rainfed conditions in the barley cultivar Fourat5 (17.52 kg grains mm -1 water year-1 ha-1), while it was significantly the lowest during the first growing season of lesser precipitation under supplementary irrigation conditions for the two varieties of barley Fourat9, and Fourat7 under the rainfed conditions (5.72, 5.82 kg grains mm-1 water year-1 ha-1 respectively).232The average nitrogen use efficiency and the nitrogen uptake efficiency were significantly higher during the second growing season under rainfed conditions in the barley cultivar Fourat5 (78.16 kg grains. Kg nitrogen available in soil-1 and 1.93 kg total nitrogen. Kg nitrogen available in soil-1. ha-1 respectively), while they were the lowest significantly during the second growing season, under supplementary irrigation conditions, in the two barley varieties Fourat9, and Araby Aswad, without significant differences between them (17.29, 18.94 kg grains. Kg nitrogen available in soil-1; 0.34, 0.40 kg total nitrogen. Kg nitrogen available in soil-1. ha-1 respectively).The mean average of phosphorous use efficiency and the average of phosphorus absorption efficiency were significant higher during the first growing season under supplemental irrigation conditions in the two barley varieties Fourat5 and Fourat4 with significant differences between them (76.89, 68.02 kg grains. Kg phosphorous available in soil-1; 28.50, 28.85 kg total phosphorus ha-1. kg Phosphorous available in soil-1. ha-1), while they were significantly the lowest during the first growing season under rainfed conditions of the barley variety7 (19.97 kg grains. Kg available phosphorous in soil-1, 7.28 kg total Phosphorus ha-1 kg. Phosphorous available in soil-1 . ha-1 respectively).The mean proline and alcohol soluble sugars content in the leaves were significantly higher during the first growing season under rainfed conditions in the two barley varieties Fourat5 and Fourat4 without significant differences between them (17.34, 16.53; 112.9, 108.8 ug g-1 green material), while they were significantly the lowest during the second growing season, under the supplementary irrigation conditions in the barley varieties Fourat9 and Fourat7 with regard to proline without significant differences between them, and in the barley varieties Fourat9, and Araby Aswad without significant differences between them, for alcohol-soluble sugars (3.29, 3.70; 46.15, 49.93 ug g-1 green material respectively). The mean of the amount of waxy material deposited on the leaves was significant highest during the first growing season under rainfed conditions in the two barley varieties Fourat6 and Araby Aswad without significant differences between them (0.794 and 0.717 mg cm-2 respectively), while it was significant the lowest during the second growing season under supplementary irrigation conditions in the barley varieties233Araby Aswad, Fourat4, Fourat9 and Fourat7 without significant differences among them (0.200, 0.203, 0.231 and 0.245 mg .cm-2 respectively).The mean dry weight of the spike at the time of flowering was significantly higher during the first growing season under supplementary irrigation conditions in the barley cultivar Fourat5 (0.92 g), while it was significantly the lowest under the rainfed conditions during the first and second growing seasons in the barley cultivar Araby Aswad without significant differences between them (0.34 and 0.38 g respectively). The average number of grains in the main spike was significantly higher during the first growing season under supplementary irrigation conditions in the two varieties of barley Fourat4 and an improved Araby Abiad with no significant differences between them (55.56 and 53.67 grains spike-1 respectively), while it was significantly the lowest during the first growing season under the rainfed conditions in the two barley cultivars Araby Aswad and Fourat9 without significant differences between them (19.33 and 21.67 grains. spike-1 respectively).The average number of grains per square meter was significantly higher during the first growing season under supplementary irrigation conditions for the barley cultivar Fourat4 (27200 grains. m-2), followed by the two barley cultivars Fourat5 and improved Araby Abiad during the first growing season under supplementary irrigation conditions without significant differences between them (25130 and 24150 grains. m-2 respectively), while it was significantly the lowest during the first growing season, under rainfed conditions in the barley cultivar Fourat7 (8334 grains. m-2). The 1000-kernel weight, biological yield and grain yield ere significantly higher during the first growing season under supplementary irrigation conditions in the barley variety Fourat5 (54.79 g, 13100.10 and 5905 kg. ha-1 respectively), while they were significantly the lowest during the first growing season under rainfed conditions in the two barley cultivars Araby Aswad and Fourat9 (32.10, 33.62 g; 5500.69, 5800.49 g; 1183 and 1211 kg. ha-1 respectively). The average of harvest index was significantly higher during the first growing season under supplementary irrigation conditions in the barley varieties Fourat4 and Fourat5 without significant differences between them (46.68 and 45.06 % respectively), while it was234significantly the lowest during the first growing season under rainfed conditions in the barley varieties Fourat7, improved Araby Abiad and Fourat9 without significant differences among them (18.36, 20.36 and 20.74 % respectively).The average grain protein content was significantly higher during the second growing season under rainfed conditions in the barley varieties Fourat4 (13.45%), followed by the barley variety Araby Aswad during the first growing season under rainfed conditions (13.40%), while it was significantly the lowest during the second growing season under supplementary irrigation conditions in the variety Fourat7 (8.64%).In general, the barley varieties Fourat5, Fourat4 and improved Araby Abiad are considered as the most adaptive to the targeted environmental conditions, because they were more adaptive to rainfed conditions and more responsive to supplementary irrigation and could maintain significantly higher grain and forage (biomass) yields (4132, 3466 and 2533 kg. ha-1; 106.2, 89.71 and 86.22 kg. ha-1 respectively), in addition, they revealed higher values of water, phosphorous and nitrogen use efficiency (16.30, 13.55 and 9.95 kg grains. ha-1; 61.56, 51.49 and 37.39 kg grains. kg-1 available phosphorus in the soil; 63.59, 52.92 and 38.39 kg grains. kg-1 available nitrogen in the soil respectively) compared with the other investigated varieties .The superiority of such varieties could be attributed to a set of morphological, physiological and biochemical traits which are associated with enhancing of drought tolerance with maintaining the production capacity. The supplementary irrigation tool is considered as one of the most important management factors to sustain the production capacity and improving the quality properties of grains under dry farming systems (rainfed conditions).There was a positive and very significant correlation between grain yield and each of the biological yield and harvest index under both the two growing seasons for the irrigated conditions (r=0.95** and r=0.95** respectively) and under the rainfed conditions too (r=0.95** and r=0.92** respectively), indicating that the economic grain yield in cereals in general and barley in particular is determined by these two physiological components.235It has alson been noticed a positive very significant correlation between the grain yield and the number of grains in the main spike, number of grains per sequre meter and 1000-kernel weight for both the growing seasons (r=0.86**, r=0.86** and r=0.56** respectively). It has been noticed that the grain yield under rainfed conditions is highly determined by the flag leaf area (r=0.80**), wate use efficiency (r= 0.99** ), nitrogen use and uptake efficiency (r=0.99** and r=0.98** respectively), phosphorous use and uptake efficiency (r=0.99** and r=0.99** respectivel), spike dry weight at flowering (r=0.88**), number of grains in the main spike (r=0.90**), biological yield (r=0. 92**) and harvest index (r=0.95**), so thess traits contributing in increasing of barley grain yield, if they were taking as selection criteria in the genetic improvement and breeding programe, especially undr dry farming systems