Mapping of Quantitative Trait Loci for Traits linked to Fusarium Head Blight Symptoms Evaluation In Barley RILs

Abstract

Fusarium head blight (FHB) is a devastating disease in small grain cereals worldwide. 14 The disease results in the reduction of grain yield and affects its quality. In addition, mycotoxins 15 accumulated in grain are harmful to both humans and animals. It has been reported that response 16 to pathogen infection may be associated with the morphological and developmental characteristics 17 of the host plant, e.g. the earliness and plant height. Despite the many studies the effective markers 18 for the selection of barley genotypes with increased resistance to FHB have not thus far been 19 developed. Therefore, exploring the genetic relationship between agronomic traits (e.g. heading 20 date or stem height) and disease resistance is of importance to the understanding of plant resistance 21 via "diesease escape" or dwarf stature. The studied plant material consisted of 100 recombinant 22 2 30 detected in the current study, in which many QTLs associated with FHB-and yield-related 31 characters were found. This study confirms that agromorphological traits are tightly related to the 32 FHB and should be taken into consideration when breeding barley plants for FHB resistance. 33 34 3 56 plants [9]. Although this method is widely used in the screening of resistant germplasms, the results 57 are subjective. Hence, different types of chromatography for identification and quantification of 58 mycotoxins in barley are commonly in use [10, 11]. However, due to the time-consuming and 59 costly nature of these methods, commercial immunometric assays, such as enzyme-linked 60 immunosorbent assay (ELISA), are frequently used for the monitoring of mycotoxin content [12, 61 13]. 62 Disease control is achieved by the deployment of resistant cultivars. However, breeding for 63 FHB resistance has proved difficult due to the complex inheritance of the resistance genes [14] 64 and the strong genotype-by-environment interaction [15]. 65 One of the several crop species most vulnerable to FHB infection is barley (Hordeum 66 vulgare L.). This species is a cereal crop of major importance, ranked the fourth grain crop in the 67 world in terms of production volume [16]. Its major uses are both as animal feed and as a 68 component of human nutrition [17, 18]. In addition, barley is perceived to be a model plant in 69 genetic study due to genome colinearity and synteny across rye, barley and wheat [19]. 70 Fusarium poses a real threat for barley plants especially in regions that are prone to have 71 long periods of wet weather during the flowering stage [4]. Host plants are most vulnerable to 72 infection during anthesis due to development of fungal spores on anthers and polen containg 73 nutrients [20]. Numerous morphological traits have been shown to be associated with FHB 74 resistance in barley [21]. Heading date, plant height, and spike characters (linked to spike 75 compactness) are mostly investigated [22, 23]. Days to heading is often negatively correlated with 76 FHB susceptibility and usually results in disease escape [24]. Hence...