QTL Identification and Mapping in Soft Spring Wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.) under Controlled Agroecological and Biological Testing Area Conditions with and without Nitrogen Fertilizer

Quantitative trait loci (QTL) of agriculturally valuable traits of soft spring wheat (Triticum aestivum L.) were mapped in two simultaneous and independent experiments that were carried out in different agronomical backgrounds with respect to nitrogen availability (i.e., with and without introduction of a mineral nitrogen fertilizer) in order to reveal the effects of physiological and genetic interaction between the genotype and the environment. In total, 94 QTLs, which determine 31 physiologically and agriculturally important traits, have been identified. The connection between the loci identified and polymorphism by certain traits has been proven. The connection between the trait expression and introduction of the fertilizer has been confirmed by both correlation analysis and the single-factor analysis of variance. The analyses of QTL and correlation, as well as the single-factor analysis of variance, showed that 15 of 31 traits varied confidently. This shows that the expression of these traits depends on the presence of nitrogen nutrition. The data obtained are important for further study of physiological and genetic regulatory mechanisms of expression of the traits that were evaluated in the system of interaction between the genotype and the environment as well as for the marker-assisted selection of wheat.     

QTL mapping of bread wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.) grown under controlled conditions of an agroecobiological testing ground

To determine the effects of physiological and genetic interaction between the genotype and environment, QTL (quantitative trait loci) mapping of valuable traits of bread wheat (Triticum aestivum L.) manifesting under controlled conditions of an agroecobiological testing ground has been first carried out. In the course of two experiments, differing from each other only by temperature and illumination regimes and providing the strict control and invariability of other growing parameters, 99 QTLs determining 30 different agronomically important traits have been identified. According to the results of the QTL mapping and a single-factor ANOVA, changes in the temperature and illumination regimes did not influence 21 of 30 studied traits, which remained stable in their manifestation; only nine traits varied under these conditions, which indicates that their manifestation is dependent on changes in these environmental factors. Both statistical approaches used in this study demonstrated complementary results; for each of them, the maximum likelihood criterion was used, statistical significance was determined, and significance of results was evaluated. The significance of a correlation between the identified QTLs and the polymorphism of individual traits studied was assessed using the threshold value of LOD (logarithm of odds) score. In addition, QTL analysis allowed a block structure of the T. aestivum genome to be revealed, the percentage of a phenotypic variability determined by each of the identified QTLs to be calculated, and the determination of which of the parents donated individual QTL alleles. The obtained results can be used for the further study of the physiological and genetic mechanisms of realization of traits evaluated within the framework of the “genotype–environment” interaction and also for the marker-assisted breeding of wheat.     

QTL Mapping of Diffuse Reflectance Indices of Leaves in Hexaploid Bread Wheat (Triticum aestivum L.)

Russian Journal of Plant Physiology - Quantitative trait loci (QTL) mapping of diffuse reflectance indices of laminas in bread wheat (Triticum aestivum L.) has been first performed under controlled...