G/ Egziabher T/Berhan (PhD)Hekele Tamrat2018-07-112023-11-082018-07-112023-11-081993-12http://etd.aau.edu.et/handle/123456789/7993This thesis presents a stu,ly on the nutrient requirements of four barley (Hord~ vulgare L.) cultivars cultivated in 'Nelmera. The cultivars were grown in two randomized complete blocks in sand culture at four levels each of P (0,0.5,3 and 5.5 mg.eq), and Ca ( 0,F,8 and 14 mg.eq.) factorialy combined. Several growth parameters were determined and leaf nutrient contents analysed. The resulting data were subjected to an analysis of variance. The results showed that there are treatment effects on the growth responses of barley, and differential response of culti'" vars to treatments. Phosphorue had a sic;nificant effect on all the growth parameters, Ihosphorus levels as low as 0.5 mg.eg. were able tel produce significantly high effects on shoot and root dry-weights, culm diameter and blade area of all cultivars. Shoot:root dryweif, ht ratios of Nech Gebs and Semereta were also significantly affected by P concentration of 0.5 mg.eq. Significantly higher yields for ear dry-weight, grain weight, and ear and tiller number per plant vccured at 3 mg.eq. of P. The effects of calcium were relatively less pronounced than that of phosphorus. Root dry~weight, shoct: rout dry-weight ratio, blade area, and grain weight of all cultivars were significantly affected by calcium application. These significances, however, were obtained only at higher levels of phosphorus in solution. Oa-application had no significant effect at lower levels of phosphorus (i.e 0 and 0.5 mg.eq.) in solution. Significant differences between leaf nutrient contents were observed only for certain cultivars. Thus, significant treatment effect on % Oa content of leaves was observed only for Keye Gebs, Percent Ii content of Enat Nech Gebs and Nech Gebs leaves showed significant differences, while the same effect for % Mg content of leaves was observed only for Enat Nech Gebs and Semereta-. There were no significant variations in % P content of any of the cultivars. Deficiency symptoms were observed in all cultivars at the lower P levels (i.e a and 0.5 mg.eq.) irrespective of Oa level in solution. Older leaves of Keye Gebs and Semereta were purplish in color while those of Enat Nech Gebs and Nech Gebs were yellowish green. These symptoms were taken to indicate P-deficiency .• Of the four cultivars studied, Semereta had the highest mean relative growth rate foll00ed by Keye Gebs, Nech Gebs and Enat Nech Gebs respectively; Morpholoe;ical differences as a result of treatment effects were also observed among the cultivars. Semereta had significantly higher grain yield, ear and tiller number per plant, and ear dry-vJeight than the vther cuI ti vars. On the other hand, it had Significantly Ivwer root and blade dry-weights. aemereta also performed better than any of the other cUltivars at very low phosphorus concentrations in solution.enBiologyThesis