eng Science and Education Publishing World Journal of Agricultural Research 2333-0678 2020-10-22 8 4 142 149 10.12691/wjar-8-4-6 WJAR2020846 article Zerihun Jalata jaluu_z@yahoo.com 1 Firew Mekbib 2 Berhane Lakew 3 Department of Plant Sciences, Faculty of Agricultural, Wollega University, Ethiopia School Plant Sciences, College of Agriculture and Environmental Sciences, Haramaya University, Ethiopia Ethiopian Institute of Agricultural Research (EIAR), Holetta Agricultural Research Center (HARC), P.O. Box: 2003 or P.O. Box 20420, Code 1000, Addis Ababa, Ethiopia The information on the nature and magnitude of genes controlling the resistance to net blotch and scald in barley is useful in resistance breeding. Thus, field experiment was conducted at Holetta, Ethiopia in 2015 on barley using six basic generations of (P1, P2, F1, F2, BC1, and BC2) which was derived from ¡®HB42¡¯x¡®Sabini¡¯ parental cross which were evaluated in RCB design with three replications to investigate the gene actions and interactions gene effects involved in controlling resistance to net blotch and scald diseases in barley. The result of scaling tests and generation mean analysis indicated the predominance of non-additive gene effects including epistasis gene effects than additive gene effects for all parameters and this was also confirmed by variance component analysis. Moreover, the digenic epistatic model failed to explain variation in generation means for all parameters may due to the presence of higher-order interaction and linkages. In general, the results suggest greater influence of non-additive genes including epistasis in the control of both disease parameters studied making early selection ineffective. And ¡®HB42¡¯ cultivar contained double resistance to scald and net blotch diseases which needs further study for its exploitation as source of resistance in improving barley yield. http://pubs.sciepub.com/wjar/8/4/6/wjar-8-4-6.pdf barley disease resistance gene effects non-allelic interaction type of gene effects