Abstract
Key message An effective approach for the further evolution of QTL markers, may be to create mapping populations for locally adapted gene pools, and to phenotype the studied trait under local conditions. Mapping populations of Polish fodder and malting spring barleys (Hordeum vulgare L.) were used to analyze traits describing short-time drought response at the seedlings stage. High-throughput genotyping (Diversity Array Technology (DArT) markers) and phenotyping techniques were used. The results showed high genetic diversity of the studied populations which allowed the creation of high-density linkage maps. There was also high diversity in the physiological responses of the barleys. Quantitative trait locus (QTL) analysis revealed 18 QTLs for nine physiological traits on all chromosomes except 1H in malting barley and 15 QTLs for five physiological traits on chromosomes 2H, 4H, 5H and 6H in fodder barley. Chromosomes 4H and 5H contained QTLs which explained most of the observed phenotypic variations in both populations. There was a major QTL for net photosynthetic rate in the malting barley located on chromosome 5H and two major QTLs for overall photochemical performance (PI) located on 5H and 7H. One major QTL related to photochemical quenching of chlorophyll fluorescence was located on chromosome 4H in fodder barley. Three QTL regions were common to both mapping populations but the corresponding regions explained different drought-induced traits. One region was for QTLs related to PSII photosynthetic activity stress index in malting barley, and the corresponding region in fodder barley was related to the water content stress index. These results are in accordance with previous studies which showed that different traits were responsible for drought tolerance variations in fodder and malting barleys.Electronic supplementary materialThe online version of this article (doi:10.1007/s00122-013-2190-x) contains supplementary material, which is available to authorized users.
Highlights
Drought tolerance is a very important yet problematic trait for plant breeders
A total of 2,032 Diversity Array Technology (DArT) markers have been mapped to 646 unique positions in Hordeum chilense recombinant inbred line (RIL) population (Rodríguez-Suárez et al 2012)
The map based on segregations in progeny from a cross of the Igri and Franka cultivars representing separate gene pools of two- and six-rowed barley contained 527 DArTs (Sharma et al 2011)
Summary
Drought tolerance is a very important yet problematic trait for plant breeders. Drought tolerance undergoes a very complex genetic control involving many genes with small effects which are greatly affected by the environment (Mir et al 2012). One of the most suitable methods for identifying genes that are involved in drought tolerance is the use of molecular markers for quantitative trait loci (QTLs). The QTLs can be used to improve the drought tolerance of the particular plant. To be able to determine QTLs for a desired trait, a genetic linkage map is required. Genetic linkage maps are constructed in a four stage process: create a mapping population, identify polymorphisms, genotype the mapping population and the parents with chosen markers, and linkage analysis of the markers (Collard et al 2005). The most commonly used mapping populations consist of 50–250 individuals that originate
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