Electronic Journal of Plant Breeding, 5(2): 158164 (June 2014) ISSN 0975928X http://sites.google.com/site/ejplantbreeding 158 1,2 ! " # 1* $ % 1 & 3 $ 4 1 Department of Genetics and Plant Breeding, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi 221005 India. 2 Indian Grassland and Fodder Research Institute, Jhansi 284003, India 3 Indian Agricultural Statistics Research Institute, New Delhi 110012 India. 4 Department of Mycology and Plant Pathology, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi 221005 India. Email: vkmbhu@gmail.com (Received: 17 Feb 2014; Accepted: 08 Apr 2014 ) Spot blotch caused by is an important fungal disease of Barley in warm humid areas of the world. In present study, 124 genotypes that includes 122 unadapted germplasm accessions and 2 cultivars of barley were evaluated for three years, to select resistant and susceptible accessions based on five components of spot blotch resistance viz., disease severity, latent period, spore load, number of spots and incubation period. Significant differences were observed among the evaluated accessions for all of the components of resistance. A significant positive correlation was recorded between disease severity, number of spots, and spore load while a significant negative correlation of disease severity was recorded with latent period and incubation period. Multiple regression analysis revealed that number of spots contributed maximum followed by latent period, spore load and incubation period towards the variation in disease severity. Clustering of accessions based on different components identified three groups. Based on the studied components, accessions BCU422, BCU1204 and BCU5092 demonstrated good performance, while BCU711, K603 and RD2506 were the most susceptible to spot blotch pathogen. Identified accessions BCU422, BCU1204 and BCU5092 can be recommended for use in breeding programs that aim to generate barley genotypes resistant to " ’: Barley, spot blotch, , germplasm, disease severity. ( Barley ( L.), one of the world’s oldest cultivated crops, is currently the fourth most important cereal crop of India. This crop has occupied wide geographic area than any other crop species (Paulitz and Steffenson, 2011). Barley is accepted as a crop having potential to be grown under drought and saline conditions. Besides its multiple uses as feed, food and malt (Jalal and Ahmad, 2011), barley flour are rich in βglucans, a nonstarch polysaccharide with many beneficial health effects (Newton et al., 2011). Spot blotch, a major foliar disease of barley is caused by the fungus (Sacc. in Sorok) Shoem. (teleomorph: Cochliobolus sativus (Ito and Kurib.) Drechsl. Ex Dastur). It occurs in the warmer and more humid regions of the world, including North and South America, Europe, Asia, Syria and Australia (Steffenson 1996; Kumar 2002; Arabi and Jawhar, 2007; Tyagi 2008). It reduces yield as well as quality of barley grain (Clark, 1979; Kiesling, 1985; Nutter 1985; Mathre, 1997; Kumar 2002). Temperature more than 25 0 C and relative humidity more than 90% are favourable for the outbreak of spot blotch. Thus, spot blotch is considered to be one of the major threats to barley cultivation under climate change. Chemical and other control measures are available to manage spot blotch, but these measures are cost ineffective and non ecofriendly. Joshi and Chand (2002) suggested in wheat that cultivar having resistance to spot blotch is most effective and can be easily included in integrated management of spot blotch. In barley a very few resistant lines have been identified and used in breeding programme, resulted a narrow genetic base of spot blotch resistance cultivars (Matus and Hayes, 2002; Condon 2008). Therefore, there is a need to identify new sources of resistance to widen the genetic bases of barley cultivars. Bilgic et al. (2006) reported that spot blotch resistance is partial and controlled by two to three genes. Partial resistance is typically a function of multiple components of resistance that contribute additively to a reduction in the rate of epidemic progress (Parlevliet, 1979). Reports on components of spot blotch in barley are few. Therefore, the aim of this study was to evaluate barley germplasm for spot blotch resistance by using different components of resistance for barley breeding programme. # # Experiment site : The experiment was conducted at agricultural research farm of Banaras Hindu University, Varanasi, India (25˚18’N lat., 83˚03’ E long. and 75 m amsl.) for three consecutive years