Septoria tritici blotch (STB) is the most aggressive disease that plagues wheat production across the world. In this study, we utilized two advanced backcross populations designated as B22 and Z86 to quest new genetic resources for STB field resistance. The populations B22 and Z86 were derived by crossing winter wheat cultivars 'Batis' and 'Zentos' with unique primary (exotic) hexaploid wheat accessions Syn022L and Syn086L, respectively. QTL analysis revealed ten QTL in the population B22 of which at five loci the introgression of exotic alleles resulted in an increase in STB resistance. The strongest exotic QTL allele was detected on chromosome 2D which decreases disease severity by 20.8%. In population Z86, five QTL were identified of which three resulted in decreasing STB severity due to the introgression of exotic alleles. Here, the strongest QTL QStb.Z86.3A was found on chromosome 3A which decreases disease severity by 19.7%. In both populations, 53% of the exotic alleles were associated to decrease STB severity suggesting the utility of primary wheat gene pool in questing new resistance resources in wheat.Key words: Septoria tritici blotch -QTL analysis -synthetic hexaploid wheat accessions Bread wheat (Triticum aestivum L.) is the major grain crop that feeds billions of humans and used as staple food for 35% of the world population. Fungal diseases are the major threats to its productivity and food security. Among fungal disease, Septoria tritici blotch (STB) is one of the most destructive diseases that affects vegetative and reproductive growth of wheat plant (Eyal and Levy 1987, Ghaffary et al. 2011). The severe epidemics of this disease can cause serious yield losses up to 60% especially in the area of frequent rain and lower night temperature in a growing season (Cornish et al. 1990). STB is caused by ascomycete fungus Zymoseptoria tritici (Desm.) Quaedvlieg & Crous, comb. nov. [syn. Septoria tritici Desm.; teleomorph Mycosphaerella graminicola (Fuckel) J. Schr€ ot.] which has been considered as one of the most aggressive and long-lasting pathogen of wheat (Stukenbrock et al. 2010, Miedaner et al. 2014). The pathogen spreads through airborne ascospores, infested crop debris and through volunteer wheat and related susceptible grass species. It has been reported that STB pathogens showed ability to develop resistance against some fungicides like azole (Cools and Fraaije 2008). Therefore, development of resistant cultivars is the most reliable and economical solution for sustainable wheat production as well as for long-term biosafety of our agriculture system.Modern wheat cultivars are established through negative selection and intensive breeding among high yielding cultivars. This process has resulted in narrowing the genetic diversity of our breeding material in general and elimination of vital genes/alleles for plant protection against diverse diseases in particular. On the other hand, fungal pathogen populations are multiplying and continuously evolving through frequent virulent changes through the co...

The aim of the present study was to develop a new cost effective PCR based CAPS marker set using advantages of high-throughput SNP genotyping. Initially, SNP survey was made using 20 diverse barley genotypes via 9k iSelect array genotyping that resulted in 6334 polymorphic SNP markers. Principle component analysis using this marker data showed fine differentiation of barley diverse gene pool. Till this end, we developed 200 SNP derived CAPS markers distributed across the genome covering around 991cM with an average marker density of 5.09cM. Further, we genotyped 68 CAPS markers in an F2 population (Cheri×ICB181160) segregating for seed color variation in barley. Genetic mapping of seed color revealed putative linkage of single nuclear gene on chromosome 1H. These findings showed the proof of concept for the development and utility of a newer cost effective genomic tool kit to analyze broader genetic resources of barley worldwide.